SERVER-31802 SERVER-31239 Remove master-slave replication and resync command.

37 files changed, 79 insertions, 2641 deletions

diff --git a/buildscripts/resmokeconfig/suites/jstestfuzz_replication_resync.yml b/buildscripts/resmokeconfig/suites/jstestfuzz_replication_resync.yml
deleted file mode 100644
index 1cd73444983..00000000000
--- a/buildscripts/resmokeconfig/suites/jstestfuzz_replication_resync.yml
+++ /dev/null
@@ -1,38 +0,0 @@
-test_kind: js_test
-
-selector:
-  roots:
-  - jstestfuzz/out/*.js
-
-executor:
-  archive:
-    hooks:
-      - BackgroundInitialSync
-  config:
-    shell_options:
-      readMode: commands
-      global_vars:
-        TestData:
-          ignoreCommandsIncompatibleWithInitialSync: true
-  hooks:
-  - class: CheckPrimary
-  - class: BackgroundInitialSync
-    use_resync: true
-    n: 1
-    shell_options:
-      global_vars:
-        TestData:
-          skipValidationOnInvalidViewDefinitions: true
-  fixture:
-    class: ReplicaSetFixture
-    mongod_options:
-      verbose: ''
-      set_parameters:
-        disableLogicalSessionCacheRefresh: false
-        enableTestCommands: 1
-        logComponentVerbosity:
-          replication: 2
-        numInitialSyncAttempts: 1
-        writePeriodicNoops: 1
-    num_nodes: 2
-    start_initial_sync_node: True
diff --git a/buildscripts/resmokeconfig/suites/replica_sets_resync_static_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/replica_sets_resync_static_jscore_passthrough.yml
deleted file mode 100644
index 0aa9d04ddc8..00000000000
--- a/buildscripts/resmokeconfig/suites/replica_sets_resync_static_jscore_passthrough.yml
+++ /dev/null
@@ -1,44 +0,0 @@
-test_kind: js_test
-
-selector:
-  roots:
-  - jstests/core/**/*.js
-  exclude_files:
-  # These tests are not expected to pass with replica-sets:
-  - jstests/core/dbadmin.js
-  - jstests/core/opcounters_write_cmd.js
-  - jstests/core/read_after_optime.js
-  - jstests/core/capped_update.js
-  # Having duplicate namespaces is not supported and will cause initial sync to fail.
-  - jstests/core/views/duplicate_ns.js
-  # Restarting the catalog on the sync source will cause the downstream node to copy only a subset
-  # of the required data.
-  - jstests/core/restart_catalog.js
-
-run_hook_interval: &run_hook_interval 20
-executor:
-  archive:
-    hooks:
-      - IntermediateInitialSync
-  config:
-    shell_options:
-      eval: "testingReplication = true;"
-      readMode: commands
-  hooks:
-  - class: CheckPrimary
-  - class: IntermediateInitialSync
-    use_resync: True
-    n: *run_hook_interval
-  - class: CleanEveryN
-    n: *run_hook_interval
-  fixture:
-    class: ReplicaSetFixture
-    mongod_options:
-      set_parameters:
-        enableTestCommands: 1
-        numInitialSyncAttempts: 1
-    num_nodes: 2
-    start_initial_sync_node: True
-    replset_config_options:
-      settings:
-        chainingAllowed: False
diff --git a/buildscripts/resmokelib/testing/hooks/initialsync.py b/buildscripts/resmokelib/testing/hooks/initialsync.py
index f3a5311dab4..328c4ac182e 100644
--- a/buildscripts/resmokelib/testing/hooks/initialsync.py
+++ b/buildscripts/resmokelib/testing/hooks/initialsync.py
@@ -23,9 +23,7 @@ class BackgroundInitialSync(interface.Hook):
     validates it, tears it down, and restarts it.
 
     This test accepts a parameter 'n' that specifies a number of tests after which it will wait for
-    replication to finish before validating and restarting the initial sync node. It also accepts
-    a parameter 'use_resync' for whether to restart the initial sync node with resync or by
-    shutting it down and restarting it.
+    replication to finish before validating and restarting the initial sync node.
 
     This requires the ReplicaSetFixture to be started with 'start_initial_sync_node=True'. If used
     at the same time as CleanEveryN, the 'n' value passed to this hook should be equal to the 'n'
@@ -34,7 +32,7 @@ class BackgroundInitialSync(interface.Hook):
 
     DEFAULT_N = cleanup.CleanEveryN.DEFAULT_N
 
-    def __init__(self, hook_logger, fixture, use_resync=False, n=DEFAULT_N, shell_options=None):
+    def __init__(self, hook_logger, fixture, n=DEFAULT_N, shell_options=None):
         if not isinstance(fixture, replicaset.ReplicaSetFixture):
             raise ValueError("`fixture` must be an instance of ReplicaSetFixture, not {}".format(
                 fixture.__class__.__name__))
@@ -42,7 +40,6 @@ class BackgroundInitialSync(interface.Hook):
         description = "Background Initial Sync"
         interface.Hook.__init__(self, hook_logger, fixture, description)
 
-        self.use_resync = use_resync
         self.n = n
         self.tests_run = 0
         self.random_restarts = 0
@@ -102,9 +99,8 @@ class BackgroundInitialSyncTestCase(jsfile.DynamicJSTestCase):
                 # If we have not restarted initial sync since the last time we ran the data
                 # validation, restart initial sync with a 20% probability.
                 if self._hook.random_restarts < 1 and random.random() < 0.2:
-                    hook_type = "resync" if self._hook.use_resync else "initial sync"
-                    self.logger.info("randomly restarting " + hook_type +
-                                     " in the middle of " + hook_type)
+                    self.logger.info(
+                        "randomly restarting initial sync in the middle of initial sync")
                     self.__restart_init_sync(sync_node, sync_node_conn)
                     self._hook.random_restarts += 1
                 return
@@ -123,35 +119,27 @@ class BackgroundInitialSyncTestCase(jsfile.DynamicJSTestCase):
 
         self.__restart_init_sync(sync_node, sync_node_conn)
 
-    # Restarts initial sync by shutting down the node, clearing its data, and restarting it,
-    # or by calling resync if use_resync is specified.
+    # Restarts initial sync by shutting down the node, clearing its data, and restarting it.
     def __restart_init_sync(self, sync_node, sync_node_conn):
-        if self._hook.use_resync:
-            self.logger.info("Calling resync on initial sync node...")
-            cmd = bson.SON([("resync", 1), ("wait", 0)])
-            sync_node_conn.admin.command(cmd)
-        else:
-            # Tear down and restart the initial sync node to start initial sync again.
-            sync_node.teardown()
+        # Tear down and restart the initial sync node to start initial sync again.
+        sync_node.teardown()
 
-            self.logger.info("Starting the initial sync node back up again...")
-            sync_node.setup()
-            sync_node.await_ready()
+        self.logger.info("Starting the initial sync node back up again...")
+        sync_node.setup()
+        sync_node.await_ready()
 
 
 class IntermediateInitialSync(interface.Hook):
     """
     This hook accepts a parameter 'n' that specifies a number of tests after which it will start up
-    a node to initial sync, wait for replication to finish, and then validate the data. It also
-    accepts a parameter 'use_resync' for whether to restart the initial sync node with resync or by
-    shutting it down and restarting it.
+    a node to initial sync, wait for replication to finish, and then validate the data.
 
     This requires the ReplicaSetFixture to be started with 'start_initial_sync_node=True'.
     """
 
     DEFAULT_N = cleanup.CleanEveryN.DEFAULT_N
 
-    def __init__(self, hook_logger, fixture, use_resync=False, n=DEFAULT_N):
+    def __init__(self, hook_logger, fixture, n=DEFAULT_N):
         if not isinstance(fixture, replicaset.ReplicaSetFixture):
             raise ValueError("`fixture` must be an instance of ReplicaSetFixture, not {}".format(
                 fixture.__class__.__name__))
@@ -159,7 +147,6 @@ class IntermediateInitialSync(interface.Hook):
         description = "Intermediate Initial Sync"
         interface.Hook.__init__(self, hook_logger, fixture, description)
 
-        self.use_resync = use_resync
         self.n = n
         self.tests_run = 0
 
@@ -195,16 +182,11 @@ class IntermediateInitialSyncTestCase(jsfile.DynamicJSTestCase):
         sync_node = self.fixture.get_initial_sync_node()
         sync_node_conn = sync_node.mongo_client()
 
-        if self._hook.use_resync:
-            self.logger.info("Calling resync on initial sync node...")
-            cmd = bson.SON([("resync", 1)])
-            sync_node_conn.admin.command(cmd)
-        else:
-            sync_node.teardown()
+        sync_node.teardown()
 
-            self.logger.info("Starting the initial sync node back up again...")
-            sync_node.setup()
-            sync_node.await_ready()
+        self.logger.info("Starting the initial sync node back up again...")
+        sync_node.setup()
+        sync_node.await_ready()
 
         # Do initial sync round.
         self.logger.info("Waiting for initial sync node to go into SECONDARY state")
diff --git a/etc/evergreen.yml b/etc/evergreen.yml
index bad5cc033ea..96bf8b2adc3 100644
--- a/etc/evergreen.yml
+++ b/etc/evergreen.yml
@@ -739,7 +739,6 @@ functions:
               case "${task_name}" in
               replica_sets_initsync_jscore_passthrough          \
               |replica_sets_initsync_static_jscore_passthrough  \
-              |replica_sets_resync_static_jscore_passthrough    \
               |replica_sets*                           \
               |sharding*                              \
               )
@@ -3032,19 +3031,6 @@ tasks:
       <<: *jstestfuzz_config_vars
       resmoke_args: --suites=jstestfuzz_replication_initsync --storageEngine=wiredTiger
 
-## jstestfuzz initial sync replica set ##
-- <<: *jstestfuzz_template
-  name: jstestfuzz_replication_resync
-  commands:
-  - func: "do setup"
-  - func: "run jstestfuzz"
-    vars:
-      jstestfuzz_vars: --numGeneratedFiles 75
-  - <<: *run_jstestfuzz_tests
-    vars:
-      <<: *jstestfuzz_config_vars
-      resmoke_args: --suites=jstestfuzz_replication_resync --storageEngine=wiredTiger
-
 ## jstestfuzz replica set with logical session ##
 - <<: *jstestfuzz_template
   name: jstestfuzz_replication_session
@@ -3544,17 +3530,6 @@ tasks:
       run_multiple_jobs: true
 
 - <<: *task_template
-  name: replica_sets_resync_static_jscore_passthrough
-  depends_on:
-  - name: jsCore
-  commands:
-  - func: "do setup"
-  - func: "run tests"
-    vars:
-      resmoke_args: --suites=replica_sets_resync_static_jscore_passthrough --storageEngine=wiredTiger
-      run_multiple_jobs: true
-
-- <<: *task_template
   name: replica_sets_kill_secondaries_jscore_passthrough
   depends_on:
   - name: jsCore
@@ -4995,7 +4970,6 @@ buildvariants:
   - name: replica_sets_initsync_static_jscore_passthrough
   - name: replica_sets_jscore_passthrough
   - name: replica_sets_kill_secondaries_jscore_passthrough
-  - name: replica_sets_resync_static_jscore_passthrough
   - name: replica_sets_pv0
   - name: retryable_writes_jscore_passthrough
   - name: retryable_writes_jscore_stepdown_passthrough
@@ -5994,9 +5968,6 @@ buildvariants:
   - name: replica_sets_initsync_static_jscore_passthrough
     distros:
     - windows-64-vs2015-large
-  - name: replica_sets_resync_static_jscore_passthrough
-    distros:
-    - windows-64-vs2015-large
   - name: replica_sets_kill_secondaries_jscore_passthrough
     distros:
     - windows-64-vs2015-large
@@ -6772,9 +6743,6 @@ buildvariants:
   - name: replica_sets_initsync_static_jscore_passthrough
     distros:
     - rhel62-large
-  - name: replica_sets_resync_static_jscore_passthrough
-    distros:
-    - rhel62-large
   - name: replica_sets_kill_secondaries_jscore_passthrough
     distros:
     - rhel62-large
@@ -6920,7 +6888,6 @@ buildvariants:
   - name: replica_sets_jscore_passthrough
   - name: replica_sets_initsync_jscore_passthrough
   - name: replica_sets_initsync_static_jscore_passthrough
-  - name: replica_sets_resync_static_jscore_passthrough
   - name: replica_sets_kill_secondaries_jscore_passthrough
   - name: retryable_writes_jscore_passthrough
   - name: sasl
@@ -8998,7 +8965,6 @@ buildvariants:
   - name: replica_sets_jscore_passthrough
   - name: replica_sets_initsync_jscore_passthrough
   - name: replica_sets_initsync_static_jscore_passthrough
-  - name: replica_sets_resync_static_jscore_passthrough
   - name: replica_sets_kill_secondaries_jscore_passthrough
   - name: retryable_writes_jscore_passthrough
   - name: retryable_writes_jscore_stepdown_passthrough
@@ -9153,7 +9119,6 @@ buildvariants:
   - name: replica_sets_jscore_passthrough
   - name: replica_sets_initsync_jscore_passthrough
   - name: replica_sets_initsync_static_jscore_passthrough
-  - name: replica_sets_resync_static_jscore_passthrough
   - name: replica_sets_kill_secondaries_jscore_passthrough
   - name: retryable_writes_jscore_passthrough
   - name: retryable_writes_jscore_stepdown_passthrough
@@ -9283,7 +9248,6 @@ buildvariants:
   - name: replica_sets_jscore_passthrough
   - name: replica_sets_initsync_jscore_passthrough
   - name: replica_sets_initsync_static_jscore_passthrough
-  - name: replica_sets_resync_static_jscore_passthrough
   - name: replica_sets_kill_secondaries_jscore_passthrough
   - name: sasl
   - name: sharded_collections_jscore_passthrough
@@ -9403,7 +9367,6 @@ buildvariants:
   - name: jstestfuzz_concurrent_sharded_session
   - name: jstestfuzz_replication
   - name: jstestfuzz_replication_initsync
-  - name: jstestfuzz_replication_resync
   - name: jstestfuzz_replication_session
   - name: jstestfuzz_sharded
   - name: jstestfuzz_sharded_causal_consistency
@@ -9433,9 +9396,6 @@ buildvariants:
   - name: replica_sets_jscore_passthrough
     distros:
     - rhel62-large
-  - name: replica_sets_resync_static_jscore_passthrough
-    distros:
-    - rhel62-large
   - name: rlp
   - name: rollback_fuzzer
   - name: serial_run
@@ -9529,7 +9489,6 @@ buildvariants:
   - name: jstestfuzz_concurrent_sharded_session
   - name: jstestfuzz_replication
   - name: jstestfuzz_replication_initsync
-  - name: jstestfuzz_replication_resync
   - name: jstestfuzz_replication_session
   - name: jstestfuzz_sharded
   - name: jstestfuzz_sharded_causal_consistency
@@ -9557,9 +9516,6 @@ buildvariants:
   - name: replica_sets_jscore_passthrough
     distros:
     - windows-64-vs2015-large
-  - name: replica_sets_resync_static_jscore_passthrough
-    distros:
-    - windows-64-vs2015-large
   - name: rollback_fuzzer
   - name: serial_run
   - name: sharded_collections_jscore_passthrough
@@ -9632,7 +9588,6 @@ buildvariants:
   - name: jstestfuzz_concurrent_sharded_session
   - name: jstestfuzz_replication
   - name: jstestfuzz_replication_initsync
-  - name: jstestfuzz_replication_resync
   - name: jstestfuzz_replication_session
   - name: jstestfuzz_sharded
   - name: jstestfuzz_sharded_causal_consistency
@@ -9650,7 +9605,6 @@ buildvariants:
   - name: replica_sets_initsync_jscore_passthrough
   - name: replica_sets_initsync_static_jscore_passthrough
   - name: replica_sets_jscore_passthrough
-  - name: replica_sets_resync_static_jscore_passthrough
   - name: rollback_fuzzer
   - name: serial_run
   - name: sharded_collections_jscore_passthrough
diff --git a/jstests/auth/lib/commands_lib.js b/jstests/auth/lib/commands_lib.js
index ea375a214f6..f40213bbaef 100644
--- a/jstests/auth/lib/commands_lib.js
+++ b/jstests/auth/lib/commands_lib.js
@@ -5199,21 +5199,6 @@ var authCommandsLib = {
           ]
         },
         {
-          testname: "resync",
-          command: {resync: 1},
-          skipSharded: true,
-          testcases: [
-              {
-                runOnDb: adminDbName,
-                roles: {hostManager: 1, clusterManager: 1, clusterAdmin: 1, root: 1, __system: 1},
-                privileges: [{resource: {cluster: true}, actions: ["resync"]}],
-                expectFail: true
-              },
-              {runOnDb: firstDbName, roles: {}},
-              {runOnDb: secondDbName, roles: {}}
-          ]
-        },
-        {
           testname: "serverStatus",
           command: {serverStatus: 1},
           testcases: [
diff --git a/jstests/core/views/views_all_commands.js b/jstests/core/views/views_all_commands.js
index e5f11d2c1b5..3dc22a53fac 100644
--- a/jstests/core/views/views_all_commands.js
+++ b/jstests/core/views/views_all_commands.js
@@ -443,7 +443,6 @@
         replSetUpdatePosition: {skip: isUnrelated},
         replSetResizeOplog: {skip: isUnrelated},
         resetError: {skip: isUnrelated},
-        resync: {skip: isUnrelated},
         revokePrivilegesFromRole: {
             command: {
                 revokePrivilegesFromRole: "testrole",
diff --git a/jstests/replsets/initial_sync_document_validation.js b/jstests/replsets/initial_sync_document_validation.js
index 1dd69e0e1d3..06d9388b51d 100644
--- a/jstests/replsets/initial_sync_document_validation.js
+++ b/jstests/replsets/initial_sync_document_validation.js
@@ -1,6 +1,5 @@
 /**
- * Tests that initial sync via resync command does not fail if it inserts documents
- * which don't validate.
+ * Tests that initial sync does not fail if it inserts documents which don't validate.
  */
 
 (function() {
@@ -19,7 +18,7 @@
     assert.writeOK(coll.insert({_id: 0, x: 1}));
     assert.commandWorked(coll.runCommand("collMod", {"validator": {a: {$exists: true}}}));
 
-    assert.commandWorked(secondary.getDB("admin").runCommand({resync: 1}));
+    secondary = replSet.restart(secondary, {startClean: true});
     replSet.awaitReplication();
     replSet.awaitSecondaryNodes();
 
diff --git a/jstests/replsets/initial_sync_fail_insert_once.js b/jstests/replsets/initial_sync_fail_insert_once.js
index a565c64216d..d85f97f5a63 100644
--- a/jstests/replsets/initial_sync_fail_insert_once.js
+++ b/jstests/replsets/initial_sync_fail_insert_once.js
@@ -24,9 +24,8 @@
         data: {collectionNS: coll.getFullName()}
     }));
 
-    jsTest.log("Issuing RESYNC command to " + tojson(secondary));
-    assert.commandWorked(secondary.getDB("admin").runCommand({resync: 1}));
-
+    jsTest.log("Re-syncing " + tojson(secondary));
+    secondary = replSet.restart(secondary, {startClean: true});
     replSet.awaitReplication();
     replSet.awaitSecondaryNodes();
 
diff --git a/jstests/replsets/read_committed_no_snapshots.js b/jstests/replsets/read_committed_no_snapshots.js
index 9adfdc37502..83ba451e836 100644
--- a/jstests/replsets/read_committed_no_snapshots.js
+++ b/jstests/replsets/read_committed_no_snapshots.js
@@ -27,7 +27,7 @@ load("jstests/replsets/rslib.js");  // For reconfig and startSetIfSupportsReadMa
         "members": [
             {"_id": 0, "host": nodes[0]},
             {"_id": 1, "host": nodes[1], priority: 0},
-            {"_id": 2, "host": nodes[2], arbiterOnly: true}
+            {"_id": 2, "host": nodes[2], priority: 0}
         ],
         "protocolVersion": 1
     };
@@ -36,12 +36,15 @@ load("jstests/replsets/rslib.js");  // For reconfig and startSetIfSupportsReadMa
 
     // Get connections and collection.
     var primary = replTest.getPrimary();
-    var secondary = replTest.liveNodes.slaves[0];
-    var secondaryId = replTest.getNodeId(secondary);
-    var db = primary.getDB(name);
+    var healthySecondary = replTest.liveNodes.slaves[0];
+    healthySecondary.setSlaveOk();
+    var noSnapshotSecondary = replTest.liveNodes.slaves[1];
+    noSnapshotSecondary.setSlaveOk();
+    assert.commandWorked(noSnapshotSecondary.adminCommand(
+        {configureFailPoint: 'disableSnapshotting', mode: 'alwaysOn'}));
 
     // Do a write, wait for it to replicate, and ensure it is visible.
-    var res = db.runCommandWithMetadata(  //
+    var res = primary.getDB(name).runCommandWithMetadata(  //
         {
           insert: "foo",
           documents: [{_id: 1, state: 0}],
@@ -50,36 +53,32 @@ load("jstests/replsets/rslib.js");  // For reconfig and startSetIfSupportsReadMa
         {"$replData": 1});
     assert.commandWorked(res.commandReply);
 
-    // We need to propagate the lastOpVisible from the primary as afterOpTime in the secondary to
-    // ensure
-    // we wait for the write to be in the majority committed view.
+    // We need to propagate the lastOpVisible from the primary as afterOpTime in the secondaries to
+    // ensure we wait for the write to be in the majority committed view.
     var lastOp = res.metadata["$replData"].lastOpVisible;
 
-    secondary.setSlaveOk();
     // Timeout is based on heartbeat timeout.
-    assert.commandWorked(secondary.getDB(name).foo.runCommand(
+    assert.commandWorked(healthySecondary.getDB(name).foo.runCommand(
         'find',
         {"readConcern": {"level": "majority", "afterOpTime": lastOp}, "maxTimeMS": 10 * 1000}));
 
-    // Disable snapshotting via failpoint
-    secondary.adminCommand({configureFailPoint: 'disableSnapshotting', mode: 'alwaysOn'});
-
-    // Resync to drop any existing snapshots
-    secondary.adminCommand({resync: 1});
-
     // Ensure maxTimeMS times out while waiting for this snapshot
-    assert.commandFailed(secondary.getDB(name).foo.runCommand(
-        'find', {"readConcern": {"level": "majority"}, "maxTimeMS": 1000}));
+    assert.commandFailedWithCode(
+        noSnapshotSecondary.getDB(name).foo.runCommand(
+            'find', {"readConcern": {"level": "majority"}, "maxTimeMS": 1000}),
+        ErrorCodes.ExceededTimeLimit);
 
-    // Reconfig to make the secondary the primary
+    // Reconfig to make the no-snapshot secondary the primary
     var config = primary.getDB("local").system.replset.findOne();
     config.members[0].priority = 0;
-    config.members[1].priority = 3;
+    config.members[2].priority = 1;
     config.version++;
     primary = reconfig(replTest, config, true);
 
     // Ensure maxTimeMS times out while waiting for this snapshot
-    assert.commandFailed(primary.getSiblingDB(name).foo.runCommand(
-        'find', {"readConcern": {"level": "majority"}, "maxTimeMS": 1000}));
+    assert.commandFailedWithCode(
+        primary.getSiblingDB(name).foo.runCommand(
+            'find', {"readConcern": {"level": "majority"}, "maxTimeMS": 1000}),
+        ErrorCodes.ExceededTimeLimit);
     replTest.stopSet();
 })();
diff --git a/jstests/replsets/resync.js b/jstests/replsets/resync.js
deleted file mode 100644
index 8a6a35ee699..00000000000
--- a/jstests/replsets/resync.js
+++ /dev/null
@@ -1,119 +0,0 @@
-// test that the resync command works with replica sets and that one does not need to manually
-// force a replica set resync by deleting all datafiles
-// Also tests that you can do this from a node that is "too stale"
-//
-// This test requires persistence in order for a restarted node with a stale oplog to stay in the
-// RECOVERING state. A restarted node with an ephemeral storage engine will not have an oplog upon
-// restart, so will immediately resync.
-// @tags: [requires_persistence]
-(function() {
-    "use strict";
-
-    var replTest = new ReplSetTest({
-        name: 'resync',
-        nodes: 3,
-        oplogSize: 1,
-        // At the end of this test we call resync on a node that may have blacklisted the only other
-        // data bearing node.  We need to ensure that the resync attempt will keep looking for a
-        // sync source for at least 60 seconds, until the blacklist period ends.  Since we sleep 1
-        // second in between each attempt to find a sync source, setting the number of attempts to
-        // find a sync source to larger than 60 should ensure that the resync attempt is able to
-        // succeed.
-        nodeOptions: {setParameter: "numInitialSyncConnectAttempts=90"}
-    });
-    var nodes = replTest.nodeList();
-
-    var conns = replTest.startSet();
-    var r = replTest.initiate({
-        "_id": "resync",
-        "members": [
-            {"_id": 0, "host": nodes[0], priority: 1},
-            {"_id": 1, "host": nodes[1], priority: 0},
-            {"_id": 2, "host": nodes[2], arbiterOnly: true}
-        ]
-    });
-
-    var a_conn = conns[0];
-    // Make sure we have a master, and it is conns[0]
-    replTest.waitForState(a_conn, ReplSetTest.State.PRIMARY);
-    var b_conn = conns[1];
-    a_conn.setSlaveOk();
-    b_conn.setSlaveOk();
-    var A = a_conn.getDB("test");
-    var B = b_conn.getDB("test");
-    var AID = replTest.getNodeId(a_conn);
-    var BID = replTest.getNodeId(b_conn);
-
-    // create an oplog entry with an insert
-    assert.writeOK(
-        A.foo.insert({x: 1}, {writeConcern: {w: 2, wtimeout: ReplSetTest.kDefaultTimeoutMS}}));
-    assert.eq(B.foo.findOne().x, 1);
-
-    // run resync and wait for it to happen
-    assert.commandWorked(b_conn.getDB("admin").runCommand({resync: 1}));
-    replTest.awaitReplication();
-    replTest.awaitSecondaryNodes();
-
-    assert.eq(B.foo.findOne().x, 1);
-    replTest.stop(BID);
-
-    function hasCycled() {
-        var oplog = a_conn.getDB("local").oplog.rs;
-        try {
-            // Collection scan to determine if the oplog entry from the first insert has been
-            // deleted yet.
-            return oplog.find({"o.x": 1}).sort({$natural: 1}).limit(10).itcount() == 0;
-        } catch (except) {
-            // An error is expected in the case that capped deletions blow away the position of the
-            // collection scan during a yield. In this case, we just try again.
-            var errorRegex = /CappedPositionLost/;
-            assert(errorRegex.test(except.message));
-            return hasCycled();
-        }
-    }
-
-    jsTestLog("Rolling over oplog");
-
-    // Make sure the oplog has rolled over on the primary and secondary that is up,
-    // so when we bring up the other replica it is "too stale"
-    for (var cycleNumber = 0; cycleNumber < 10; cycleNumber++) {
-        // insert enough to cycle oplog
-        var bulk = A.foo.initializeUnorderedBulkOp();
-        for (var i = 2; i < 10000; i++) {
-            bulk.insert({x: i});
-        }
-
-        // wait for secondary to also have its oplog cycle
-        assert.writeOK(bulk.execute({w: 1, wtimeout: ReplSetTest.kDefaultTimeoutMS}));
-
-        if (hasCycled())
-            break;
-    }
-
-    assert(hasCycled());
-
-    jsTestLog("Restarting node B");
-    // bring node B and it will enter recovery mode because its newest oplog entry is too old
-    replTest.restart(BID);
-
-    jsTestLog("Waiting for node B to to into RECOVERING");
-    // check that it is in recovery mode
-    assert.soon(function() {
-        try {
-            var result = b_conn.getDB("admin").runCommand({replSetGetStatus: 1});
-            return (result.members[1].stateStr === "RECOVERING");
-        } catch (e) {
-            print(e);
-        }
-    }, "node didn't enter RECOVERING state");
-
-    jsTestLog("Resync node B");
-    // run resync and wait for it to happen
-    assert.commandWorked(b_conn.getDB("admin").runCommand({resync: 1}));
-    replTest.awaitReplication();
-    replTest.awaitSecondaryNodes();
-    assert.eq(B.foo.findOne().x, 1);
-
-    replTest.stopSet(15);
-    jsTest.log("success");
-})();
diff --git a/jstests/replsets/resync_with_write_load.js b/jstests/replsets/resync_with_write_load.js
deleted file mode 100644
index 10df8501b91..00000000000
--- a/jstests/replsets/resync_with_write_load.js
+++ /dev/null
@@ -1,93 +0,0 @@
-/**
- * This test creates a replica set and  writes during the resync call in order to verify
- * that all phases of the resync/initial-sync process work correctly.
- *
- */
-
-// Test disabled because resync still has a race where it doesn't reset its last fetched optime
-// before trying to run initial sync, which results in an upstream query with a $gte that might
-// return an empty batch.
-if (false) {
-    var testName = "resync_with_write_load";
-    var replTest = new ReplSetTest({name: testName, nodes: 3, oplogSize: 100});
-    var nodes = replTest.nodeList();
-
-    var conns = replTest.startSet();
-    var config = {
-        "_id": testName,
-        "members": [
-            {"_id": 0, "host": nodes[0]},
-            {"_id": 1, "host": nodes[1], priority: 0},
-            {"_id": 2, "host": nodes[2], priority: 0}
-        ],
-        settings: {chainingAllowed: false}
-    };
-    var r = replTest.initiate(config);
-    replTest.waitForState(replTest.nodes[0], ReplSetTest.State.PRIMARY);
-    // Make sure we have a master
-    var master = replTest.getPrimary();
-    var a_conn = conns[0];
-    var b_conn = conns[1];
-    a_conn.setSlaveOk();
-    b_conn.setSlaveOk();
-    var A = a_conn.getDB("test");
-    var B = b_conn.getDB("test");
-    var AID = replTest.getNodeId(a_conn);
-    var BID = replTest.getNodeId(b_conn);
-
-    assert(master == conns[0], "conns[0] assumed to be master");
-    assert(a_conn.host == master.host);
-
-    // create an oplog entry with an insert
-    assert.writeOK(
-        A.foo.insert({x: 1}, {writeConcern: {w: 3, wtimeout: ReplSetTest.kDefaultTimeoutMS}}));
-
-    print("******************** starting load for 30 secs *********************");
-    var work = function() {
-        print("starting loadgen");
-        var start = new Date().getTime();
-
-        assert.writeOK(db.timeToStartTrigger.insert({_id: 1}));
-
-        while (true) {
-            for (x = 0; x < 100; x++) {
-                db["a" + x].insert({a: x});
-            }
-
-            var runTime = (new Date().getTime() - start);
-            if (runTime > 30000)
-                break;
-            else if (runTime < 5000)  // back-off more during first 2 seconds
-                sleep(50);
-            else
-                sleep(1);
-        }
-        print("finshing loadgen");
-    };
-    // insert enough that resync node has to go through oplog replay in each step
-    var loadGen = startParallelShell(work, replTest.ports[0]);
-
-    // wait for document to appear to continue
-    assert.soon(function() {
-        try {
-            return 1 == master.getDB("test")["timeToStartTrigger"].find().itcount();
-        } catch (e) {
-            print(e);
-            return false;
-        }
-    }, "waited too long for start trigger", 90 * 1000 /* 90 secs */);
-
-    print("*************** issuing resync command ***************");
-    assert.commandWorked(B.adminCommand("resync"));
-
-    print("waiting for load generation to finish");
-    loadGen();
-
-    // Make sure oplogs & dbHashes match
-    replTest.checkOplogs(testName);
-    replTest.checkReplicatedDataHashes(testName);
-
-    replTest.stopSet();
-
-    print("*****test done******");
-}
diff --git a/src/mongo/db/commands/count_cmd.cpp b/src/mongo/db/commands/count_cmd.cpp
index a91561f6da6..85a6e1f02c8 100644
--- a/src/mongo/db/commands/count_cmd.cpp
+++ b/src/mongo/db/commands/count_cmd.cpp
@@ -41,7 +41,6 @@
 #include "mongo/db/query/get_executor.h"
 #include "mongo/db/query/plan_summary_stats.h"
 #include "mongo/db/query/view_response_formatter.h"
-#include "mongo/db/repl/replication_coordinator.h"
 #include "mongo/db/views/resolved_view.h"
 #include "mongo/util/log.h"
 
@@ -68,10 +67,6 @@ public:
     }
 
     AllowedOnSecondary secondaryAllowed(ServiceContext* serviceContext) const override {
-        if (repl::ReplicationCoordinator::get(serviceContext)->getSettings().isSlave()) {
-            // ok on --slave setups
-            return Command::AllowedOnSecondary::kAlways;
-        }
         return Command::AllowedOnSecondary::kOptIn;
     }
 
diff --git a/src/mongo/db/db.cpp b/src/mongo/db/db.cpp
index d52ef2343f2..85eb916a6fe 100644
--- a/src/mongo/db/db.cpp
+++ b/src/mongo/db/db.cpp
@@ -294,10 +294,6 @@ ExitCode _initAndListen(int listenPort) {
         LogstreamBuilder l = log(LogComponent::kControl);
         l << "MongoDB starting : pid=" << pid << " port=" << serverGlobalParams.port
           << " dbpath=" << storageGlobalParams.dbpath;
-        if (replSettings.isMaster())
-            l << " master=" << replSettings.isMaster();
-        if (replSettings.isSlave())
-            l << " slave=" << (int)replSettings.isSlave();
 
         const bool is32bit = sizeof(int*) == 4;
         l << (is32bit ? " 32" : " 64") << "-bit host=" << getHostNameCached() << endl;
@@ -398,8 +394,8 @@ ExitCode _initAndListen(int listenPort) {
 
     auto startupOpCtx = serviceContext->makeOperationContext(&cc());
 
-    bool canCallFCVSetIfCleanStartup = !storageGlobalParams.readOnly &&
-        !(replSettings.isSlave() || storageGlobalParams.engine == "devnull");
+    bool canCallFCVSetIfCleanStartup =
+        !storageGlobalParams.readOnly && (storageGlobalParams.engine != "devnull");
     if (canCallFCVSetIfCleanStartup && !replSettings.usingReplSets()) {
         Lock::GlobalWrite lk(startupOpCtx.get());
         FeatureCompatibilityVersion::setIfCleanStartup(startupOpCtx.get(),
@@ -560,8 +556,7 @@ ExitCode _initAndListen(int listenPort) {
             startTTLBackgroundJob();
         }
 
-        if (replSettings.usingReplSets() || (!replSettings.isMaster() && replSettings.isSlave()) ||
-            !internalValidateFeaturesAsMaster) {
+        if (replSettings.usingReplSets() || !internalValidateFeaturesAsMaster) {
             serverGlobalParams.validateFeaturesAsMaster.store(false);
         }
     }
diff --git a/src/mongo/db/logical_clock_test_fixture.cpp b/src/mongo/db/logical_clock_test_fixture.cpp
index 2d384c83274..66ae1b889f1 100644
--- a/src/mongo/db/logical_clock_test_fixture.cpp
+++ b/src/mongo/db/logical_clock_test_fixture.cpp
@@ -61,9 +61,6 @@ void LogicalClockTestFixture::setUp() {
 
     _dbDirectClient = stdx::make_unique<DBDirectClient>(operationContext());
 
-    // Set master to false (set to true in ShardingMongodTestFixture::setUp()) so follower mode can
-    // be toggled meaningfully. Default follower mode to primary, so writes can be accepted.
-    replicationCoordinator()->setMaster(false);
     ASSERT_OK(replicationCoordinator()->setFollowerMode(repl::MemberState::RS_PRIMARY));
 }
 
diff --git a/src/mongo/db/mongod_options.cpp b/src/mongo/db/mongod_options.cpp
index cde2a2a1a3b..a466fa4313f 100644
--- a/src/mongo/db/mongod_options.cpp
+++ b/src/mongo/db/mongod_options.cpp
@@ -82,7 +82,6 @@ Status addMongodOptions(moe::OptionSection* options) {
     }
 #endif
 
-    moe::OptionSection ms_options("Master/slave options (old; use replica sets instead)");
     moe::OptionSection rs_options("Replica set options");
     moe::OptionSection replication_options("Replication options");
     moe::OptionSection sharding_options("Sharding options");
@@ -370,49 +369,6 @@ Status addMongodOptions(moe::OptionSection* options) {
 
 #endif
 
-    // Master Slave Options
-
-    ms_options.addOptionChaining("master", "master", moe::Switch, "master mode")
-        .incompatibleWith("replication.replSet")
-        .incompatibleWith("replication.replSetName")
-        .setSources(moe::SourceAllLegacy);
-
-    ms_options.addOptionChaining("slave", "slave", moe::Switch, "slave mode")
-        .incompatibleWith("replication.replSet")
-        .incompatibleWith("replication.replSetName")
-        .setSources(moe::SourceAllLegacy);
-
-    ms_options
-        .addOptionChaining(
-            "source", "source", moe::String, "when slave: specify master as <server:port>")
-        .incompatibleWith("replication.replSet")
-        .incompatibleWith("replication.replSetName")
-        .setSources(moe::SourceAllLegacy);
-
-    ms_options
-        .addOptionChaining(
-            "only", "only", moe::String, "when slave: specify a single database to replicate")
-        .incompatibleWith("replication.replSet")
-        .incompatibleWith("replication.replSetName")
-        .setSources(moe::SourceAllLegacy);
-
-    ms_options
-        .addOptionChaining(
-            "slavedelay",
-            "slavedelay",
-            moe::Int,
-            "specify delay (in seconds) to be used when applying master ops to slave")
-        .incompatibleWith("replication.replSet")
-        .incompatibleWith("replication.replSetName")
-        .setSources(moe::SourceAllLegacy);
-
-    ms_options
-        .addOptionChaining(
-            "autoresync", "autoresync", moe::Switch, "automatically resync if slave data is stale")
-        .incompatibleWith("replication.replSet")
-        .incompatibleWith("replication.replSetName")
-        .setSources(moe::SourceAllLegacy);
-
     // Replication Options
 
     replication_options.addOptionChaining(
@@ -468,9 +424,7 @@ Status addMongodOptions(moe::OptionSection* options) {
                            moe::Switch,
                            "declare this is a shard db of a cluster; default port 27018")
         .setSources(moe::SourceAllLegacy)
-        .incompatibleWith("configsvr")
-        .incompatibleWith("master")
-        .incompatibleWith("slave");
+        .incompatibleWith("configsvr");
 
     sharding_options
         .addOptionChaining(
@@ -530,7 +484,6 @@ Status addMongodOptions(moe::OptionSection* options) {
     options->addSection(windows_scm_options).transitional_ignore();
 #endif
     options->addSection(replication_options).transitional_ignore();
-    options->addSection(ms_options).transitional_ignore();
     options->addSection(rs_options).transitional_ignore();
     options->addSection(sharding_options).transitional_ignore();
 #ifdef MONGO_CONFIG_SSL
@@ -540,23 +493,6 @@ Status addMongodOptions(moe::OptionSection* options) {
 
     // The following are legacy options that are disallowed in the JSON config file
 
-    options
-        ->addOptionChaining(
-            "fastsync",
-            "fastsync",
-            moe::Switch,
-            "indicate that this instance is starting from a dbpath snapshot of the repl peer")
-        .hidden()
-        .setSources(moe::SourceAllLegacy);
-
-    options
-        ->addOptionChaining("pretouch",
-                            "pretouch",
-                            moe::Int,
-                            "n pretouch threads for applying master/slave operations")
-        .hidden()
-        .setSources(moe::SourceAllLegacy);
-
     // This is a deprecated option that we are supporting for backwards compatibility
     // The first value for this option can be either 'dbpath' or 'run'.
     // If it is 'dbpath', mongod prints the dbpath and exits.  Any extra values are ignored.
@@ -651,18 +587,8 @@ Status validateMongodOptions(const moe::Environment& params) {
 
     if (params.count("storage.queryableBackupMode")) {
         // Command line options that are disallowed when --queryableBackupMode is specified.
-        for (const auto& disallowedOption : {"replication.replSet",
-                                             "configsvr",
-                                             "upgrade",
-                                             "repair",
-                                             "profile",
-                                             "master",
-                                             "slave",
-                                             "source",
-                                             "only",
-                                             "slavedelay",
-                                             "autoresync",
-                                             "fastsync"}) {
+        for (const auto& disallowedOption :
+             {"replication.replSet", "configsvr", "upgrade", "repair", "profile"}) {
             if (params.count(disallowedOption)) {
                 return Status(ErrorCodes::BadValue,
                               str::stream() << "Cannot specify both queryable backup mode and "
@@ -1097,32 +1023,6 @@ Status storeMongodOptions(const moe::Environment& params) {
     }
 
     repl::ReplSettings replSettings;
-    if (params.count("master")) {
-        replSettings.setMaster(params["master"].as<bool>());
-    }
-    if (params.count("slave") && params["slave"].as<bool>() == true) {
-        replSettings.setSlave(true);
-    }
-    if (params.count("slavedelay")) {
-        replSettings.setSlaveDelaySecs(params["slavedelay"].as<int>());
-    }
-    if (params.count("fastsync")) {
-        if (!replSettings.isSlave()) {
-            return Status(ErrorCodes::BadValue,
-                          str::stream() << "--fastsync must only be used with --slave");
-        }
-        replSettings.setFastSyncEnabled(params["fastsync"].as<bool>());
-    }
-    if (params.count("autoresync")) {
-        replSettings.setAutoResyncEnabled(params["autoresync"].as<bool>());
-    }
-    if (params.count("source")) {
-        /* specifies what the source in local.sources should be */
-        replSettings.setSource(params["source"].as<std::string>().c_str());
-    }
-    if (params.count("pretouch")) {
-        replSettings.setPretouch(params["pretouch"].as<int>());
-    }
     if (params.count("replication.replSetName")) {
         replSettings.setReplSetString(params["replication.replSetName"].as<std::string>().c_str());
     }
@@ -1147,9 +1047,6 @@ Status storeMongodOptions(const moe::Environment& params) {
         serverGlobalParams.indexBuildRetry = params["storage.indexBuildRetry"].as<bool>();
     }
 
-    if (params.count("only")) {
-        replSettings.setOnly(params["only"].as<std::string>().c_str());
-    }
     if (params.count("storage.mmapv1.nsSize")) {
         int x = params["storage.mmapv1.nsSize"].as<int>();
         if (x <= 0 || x > (0x7fffffff / 1024 / 1024)) {
@@ -1272,9 +1169,6 @@ Status storeMongodOptions(const moe::Environment& params) {
         storageGlobalParams.repairpath = storageGlobalParams.dbpath;
     }
 
-    if (replSettings.getPretouch())
-        log() << "--pretouch " << replSettings.getPretouch();
-
     // Check if we are 32 bit and have not explicitly specified any journaling options
     if (sizeof(void*) == 4 && !params.count("storage.journal.enabled")) {
         // trying to make this stand out more like startup warnings
diff --git a/src/mongo/db/repair_database_and_check_version.cpp b/src/mongo/db/repair_database_and_check_version.cpp
index eceed6b3198..d86c0da16af 100644
--- a/src/mongo/db/repair_database_and_check_version.cpp
+++ b/src/mongo/db/repair_database_and_check_version.cpp
@@ -366,8 +366,7 @@ StatusWith<bool> repairDatabasesAndCheckVersion(OperationContext* opCtx) {
     // to. The local DB is special because it is not replicated.  See SERVER-10927 for more
     // details.
     const bool shouldClearNonLocalTmpCollections =
-        !(checkIfReplMissingFromCommandLine(opCtx) || replSettings.usingReplSets() ||
-          replSettings.isSlave());
+        !(checkIfReplMissingFromCommandLine(opCtx) || replSettings.usingReplSets());
 
     // To check whether a featureCompatibilityVersion document exists.
     bool fcvDocumentExists = false;
diff --git a/src/mongo/db/repl/SConscript b/src/mongo/db/repl/SConscript
index 5cebfed131d..6200fb4b39a 100644
--- a/src/mongo/db/repl/SConscript
+++ b/src/mongo/db/repl/SConscript
@@ -1535,10 +1535,8 @@ env.Library(
 env.Library(
     target="serveronly_repl",
     source=[
-        "master_slave.cpp",
         'noop_writer.cpp',
         "replication_coordinator_external_state_impl.cpp",
-        "resync.cpp",
         "rs_sync.cpp",
         "sync_source_feedback.cpp",
     ],
diff --git a/src/mongo/db/repl/master_slave.cpp b/src/mongo/db/repl/master_slave.cpp
deleted file mode 100644
index 4f8a109702b..00000000000
--- a/src/mongo/db/repl/master_slave.cpp
+++ /dev/null
@@ -1,1462 +0,0 @@
-/**
-*    Copyright (C) 2008-2014 MongoDB Inc.
-*
-*    This program is free software: you can redistribute it and/or  modify
-*    it under the terms of the GNU Affero General Public License, version 3,
-*    as published by the Free Software Foundation.
-*
-*    This program is distributed in the hope that it will be useful,
-*    but WITHOUT ANY WARRANTY; without even the implied warranty of
-*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-*    GNU Affero General Public License for more details.
-*
-*    You should have received a copy of the GNU Affero General Public License
-*    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*
-*    As a special exception, the copyright holders give permission to link the
-*    code of portions of this program with the OpenSSL library under certain
-*    conditions as described in each individual source file and distribute
-*    linked combinations including the program with the OpenSSL library. You
-*    must comply with the GNU Affero General Public License in all respects for
-*    all of the code used other than as permitted herein. If you modify file(s)
-*    with this exception, you may extend this exception to your version of the
-*    file(s), but you are not obligated to do so. If you do not wish to do so,
-*    delete this exception statement from your version. If you delete this
-*    exception statement from all source files in the program, then also delete
-*    it in the license file.
-*/
-
-/* Collections we use:
-
-   local.sources         - indicates what sources we pull from as a "slave", and the last update of
-                           each
-   local.oplog.$main     - our op log as "master"
-   local.dbinfo.<dbname> - no longer used???
-   local.pair.startup    - [deprecated] can contain a special value indicating for a pair that we
-                           have the master copy.
-                           used when replacing other half of the pair which has permanently failed.
-   local.pair.sync       - [deprecated] { initialsynccomplete: 1 }
-*/
-
-#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplication
-
-#include "mongo/platform/basic.h"
-
-#include "mongo/db/repl/master_slave.h"
-
-#include <pcrecpp.h>
-
-#include "mongo/db/auth/authorization_manager.h"
-#include "mongo/db/auth/authorization_session.h"
-#include "mongo/db/catalog/database_catalog_entry.h"
-#include "mongo/db/catalog/database_holder.h"
-#include "mongo/db/catalog/document_validation.h"
-#include "mongo/db/client.h"
-#include "mongo/db/cloner.h"
-#include "mongo/db/commands.h"
-#include "mongo/db/db_raii.h"
-#include "mongo/db/dbdirectclient.h"
-#include "mongo/db/dbhelpers.h"
-#include "mongo/db/namespace_string.h"
-#include "mongo/db/op_observer.h"
-#include "mongo/db/ops/update.h"
-#include "mongo/db/query/internal_plans.h"
-#include "mongo/db/repl/handshake_args.h"
-#include "mongo/db/repl/oplog.h"
-#include "mongo/db/repl/repl_client_info.h"
-#include "mongo/db/repl/replication_coordinator.h"
-#include "mongo/db/repl/sync_tail.h"
-#include "mongo/db/server_parameters.h"
-#include "mongo/db/service_context.h"
-#include "mongo/db/storage/storage_options.h"
-#include "mongo/platform/atomic_word.h"
-#include "mongo/stdx/thread.h"
-#include "mongo/util/exit.h"
-#include "mongo/util/log.h"
-#include "mongo/util/net/sock.h"
-#include "mongo/util/quick_exit.h"
-
-using std::cout;
-using std::endl;
-using std::max;
-using std::min;
-using std::set;
-using std::stringstream;
-using std::unique_ptr;
-using std::vector;
-
-namespace mongo {
-namespace repl {
-
-namespace {
-time_t lastForcedResync = 0;
-
-const int forceReconnect = -1;
-const int restartSync = 0;
-const int restartSyncAfterSleep = 1;
-}  // namespace
-
-void pretouchOperation(OperationContext* opCtx, const BSONObj& op);
-void pretouchN(const vector<BSONObj>&, unsigned a, unsigned b);
-
-/* if 1 sync() is running */
-AtomicInt32 syncing(0);
-AtomicInt32 relinquishSyncingSome(0);
-
-/* output by the web console */
-const char* replInfo = "";
-struct ReplInfo {
-    ReplInfo(const char* msg) {
-        replInfo = msg;
-    }
-    ~ReplInfo() {
-        replInfo = "?";
-    }
-};
-
-
-ReplSource::ReplSource(OperationContext* opCtx) {
-    nClonedThisPass = 0;
-    ensureMe(opCtx);
-}
-
-ReplSource::ReplSource(OperationContext* opCtx, BSONObj o) : nClonedThisPass(0) {
-    only = o.getStringField("only");
-    hostName = o.getStringField("host");
-    _sourceName = o.getStringField("source");
-    uassert(10118, "'host' field not set in sources collection object", !hostName.empty());
-    uassert(10119, "only source='main' allowed for now with replication", sourceName() == "main");
-    BSONElement e = o.getField("syncedTo");
-    if (!e.eoo()) {
-        uassert(10120,
-                "bad sources 'syncedTo' field value",
-                e.type() == Date || e.type() == bsonTimestamp);
-        Timestamp tmp(e.date());
-        syncedTo = tmp;
-    }
-
-    BSONObj dbsObj = o.getObjectField("dbsNextPass");
-    if (!dbsObj.isEmpty()) {
-        BSONObjIterator i(dbsObj);
-        while (1) {
-            BSONElement e = i.next();
-            if (e.eoo())
-                break;
-            addDbNextPass.insert(e.fieldName());
-        }
-    }
-
-    dbsObj = o.getObjectField("incompleteCloneDbs");
-    if (!dbsObj.isEmpty()) {
-        BSONObjIterator i(dbsObj);
-        while (1) {
-            BSONElement e = i.next();
-            if (e.eoo())
-                break;
-            incompleteCloneDbs.insert(e.fieldName());
-        }
-    }
-    ensureMe(opCtx);
-}
-
-/* Turn our C++ Source object into a BSONObj */
-BSONObj ReplSource::jsobj() {
-    BSONObjBuilder b;
-    b.append("host", hostName);
-    b.append("source", sourceName());
-    if (!only.empty())
-        b.append("only", only);
-    if (!syncedTo.isNull())
-        b.append("syncedTo", syncedTo);
-
-    BSONObjBuilder dbsNextPassBuilder;
-    int n = 0;
-    for (set<std::string>::iterator i = addDbNextPass.begin(); i != addDbNextPass.end(); i++) {
-        n++;
-        dbsNextPassBuilder.appendBool(*i, 1);
-    }
-    if (n)
-        b.append("dbsNextPass", dbsNextPassBuilder.done());
-
-    BSONObjBuilder incompleteCloneDbsBuilder;
-    n = 0;
-    for (set<std::string>::iterator i = incompleteCloneDbs.begin(); i != incompleteCloneDbs.end();
-         i++) {
-        n++;
-        incompleteCloneDbsBuilder.appendBool(*i, 1);
-    }
-    if (n)
-        b.append("incompleteCloneDbs", incompleteCloneDbsBuilder.done());
-
-    return b.obj();
-}
-
-void ReplSource::ensureMe(OperationContext* opCtx) {
-    std::string myname = getHostName();
-
-    // local.me is an identifier for a server for getLastError w:2+
-    bool exists = Helpers::getSingleton(opCtx, "local.me", _me);
-
-    if (!exists || !_me.hasField("host") || _me["host"].String() != myname) {
-        Lock::DBLock dblk(opCtx, "local", MODE_X);
-        WriteUnitOfWork wunit(opCtx);
-        // clean out local.me
-        Helpers::emptyCollection(opCtx, NamespaceString("local.me"));
-
-        // repopulate
-        BSONObjBuilder b;
-        b.appendOID("_id", 0, true);
-        b.append("host", myname);
-        _me = b.obj();
-        Helpers::putSingleton(opCtx, "local.me", _me);
-        wunit.commit();
-    }
-    _me = _me.getOwned();
-}
-
-void ReplSource::save(OperationContext* opCtx) {
-    BSONObjBuilder b;
-    verify(!hostName.empty());
-    b.append("host", hostName);
-    // todo: finish allowing multiple source configs.
-    // this line doesn't work right when source is null, if that is allowed as it is now:
-    // b.append("source", _sourceName);
-    BSONObj pattern = b.done();
-
-    BSONObj o = jsobj();
-    LOG(1) << "Saving repl source: " << o << endl;
-
-    {
-        OldClientContext ctx(opCtx, "local.sources", false);
-
-        const NamespaceString requestNs("local.sources");
-        UpdateRequest request(requestNs);
-
-        request.setQuery(pattern);
-        request.setUpdates(o);
-        request.setUpsert();
-
-        UpdateResult res = update(opCtx, ctx.db(), request);
-
-        verify(!res.modifiers);
-        verify(res.numMatched == 1 || !res.upserted.isEmpty());
-    }
-}
-
-static void addSourceToList(OperationContext* opCtx,
-                            ReplSource::SourceVector& v,
-                            ReplSource& s,
-                            ReplSource::SourceVector& old) {
-    if (!s.syncedTo.isNull()) {  // Don't reuse old ReplSource if there was a forced resync.
-        for (ReplSource::SourceVector::iterator i = old.begin(); i != old.end();) {
-            if (s == **i) {
-                v.push_back(*i);
-                old.erase(i);
-                return;
-            }
-            i++;
-        }
-    }
-
-    v.push_back(std::shared_ptr<ReplSource>(new ReplSource(s)));
-}
-
-/* we reuse our existing objects so that we can keep our existing connection
-   and cursor in effect.
-*/
-void ReplSource::loadAll(OperationContext* opCtx, SourceVector& v) {
-    const char* localSources = "local.sources";
-    OldClientContext ctx(opCtx, localSources, false);
-    SourceVector old = v;
-    v.clear();
-
-    const ReplSettings& replSettings = ReplicationCoordinator::get(opCtx)->getSettings();
-    if (!replSettings.getSource().empty()) {
-        // --source <host> specified.
-        // check that no items are in sources other than that
-        // add if missing
-        int n = 0;
-        auto exec = InternalPlanner::collectionScan(opCtx,
-                                                    localSources,
-                                                    ctx.db()->getCollection(opCtx, localSources),
-                                                    PlanExecutor::NO_YIELD);
-        BSONObj obj;
-        PlanExecutor::ExecState state;
-        while (PlanExecutor::ADVANCED == (state = exec->getNext(&obj, NULL))) {
-            n++;
-            ReplSource tmp(opCtx, obj);
-            if (tmp.hostName != replSettings.getSource()) {
-                log() << "--source " << replSettings.getSource() << " != " << tmp.hostName
-                      << " from local.sources collection" << endl;
-                log() << "for instructions on changing this slave's source, see:" << endl;
-                log() << "http://dochub.mongodb.org/core/masterslave" << endl;
-                log() << "terminating mongod after 30 seconds" << endl;
-                sleepsecs(30);
-                quickExit(EXIT_REPLICATION_ERROR);
-            }
-            if (tmp.only != replSettings.getOnly()) {
-                log() << "--only " << replSettings.getOnly() << " != " << tmp.only
-                      << " from local.sources collection" << endl;
-                log() << "terminating after 30 seconds" << endl;
-                sleepsecs(30);
-                quickExit(EXIT_REPLICATION_ERROR);
-            }
-        }
-        uassert(17065, "Internal error reading from local.sources", PlanExecutor::IS_EOF == state);
-        uassert(10002, "local.sources collection corrupt?", n < 2);
-        if (n == 0) {
-            // source missing.  add.
-            ReplSource s(opCtx);
-            s.hostName = replSettings.getSource();
-            s.only = replSettings.getOnly();
-            s.save(opCtx);
-        }
-    } else {
-        try {
-            massert(10384, "--only requires use of --source", replSettings.getOnly().empty());
-        } catch (...) {
-            quickExit(EXIT_BADOPTIONS);
-        }
-    }
-
-    auto exec = InternalPlanner::collectionScan(
-        opCtx, localSources, ctx.db()->getCollection(opCtx, localSources), PlanExecutor::NO_YIELD);
-    BSONObj obj;
-    PlanExecutor::ExecState state;
-    while (PlanExecutor::ADVANCED == (state = exec->getNext(&obj, NULL))) {
-        ReplSource tmp(opCtx, obj);
-        if (tmp.syncedTo.isNull()) {
-            DBDirectClient c(opCtx);
-            BSONObj op = c.findOne("local.oplog.$main",
-                                   QUERY("op" << NE << "n").sort(BSON("$natural" << -1)));
-            if (!op.isEmpty()) {
-                tmp.syncedTo = op["ts"].timestamp();
-            }
-        }
-        addSourceToList(opCtx, v, tmp, old);
-    }
-    uassert(17066, "Internal error reading from local.sources", PlanExecutor::IS_EOF == state);
-}
-
-bool ReplSource::throttledForceResyncDead(OperationContext* opCtx, const char* requester) {
-    if (time(0) - lastForcedResync > 600) {
-        forceResyncDead(opCtx, requester);
-        lastForcedResync = time(0);
-        return true;
-    }
-    return false;
-}
-
-void ReplSource::forceResyncDead(OperationContext* opCtx, const char* requester) {
-    if (!replAllDead)
-        return;
-    SourceVector sources;
-    ReplSource::loadAll(opCtx, sources);
-    for (SourceVector::iterator i = sources.begin(); i != sources.end(); ++i) {
-        log() << requester << " forcing resync from " << (*i)->hostName << endl;
-        (*i)->forceResync(opCtx, requester);
-    }
-    replAllDead = 0;
-}
-
-class HandshakeCmd : public BasicCommand {
-public:
-    std::string help() const override {
-        return "internal";
-    }
-    HandshakeCmd() : BasicCommand("handshake") {}
-    virtual bool supportsWriteConcern(const BSONObj& cmd) const override {
-        return false;
-    }
-    AllowedOnSecondary secondaryAllowed(ServiceContext*) const override {
-        return AllowedOnSecondary::kAlways;
-    }
-    virtual bool adminOnly() const {
-        return false;
-    }
-    virtual void addRequiredPrivileges(const std::string& dbname,
-                                       const BSONObj& cmdObj,
-                                       std::vector<Privilege>* out) const {
-        ActionSet actions;
-        actions.addAction(ActionType::internal);
-        out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
-    }
-
-    virtual bool run(OperationContext* opCtx,
-                     const std::string& ns,
-                     const BSONObj& cmdObj,
-                     BSONObjBuilder& result) {
-        HandshakeArgs handshake;
-        Status status = handshake.initialize(cmdObj);
-        if (!status.isOK()) {
-            return CommandHelpers::appendCommandStatus(result, status);
-        }
-
-        ReplClientInfo::forClient(opCtx->getClient()).setRemoteID(handshake.getRid());
-
-        status = ReplicationCoordinator::get(opCtx)->processHandshake(opCtx, handshake);
-        return CommandHelpers::appendCommandStatus(result, status);
-    }
-
-} handshakeCmd;
-
-bool replHandshake(DBClientConnection* conn, const OID& myRID) {
-    std::string myname = getHostName();
-
-    BSONObjBuilder cmd;
-    cmd.append("handshake", myRID);
-
-    BSONObj res;
-    bool ok = conn->runCommand("admin", cmd.obj(), res);
-    // ignoring for now on purpose for older versions
-    LOG(ok ? 1 : 0) << "replHandshake result: " << res << endl;
-    return true;
-}
-
-bool ReplSource::_connect(OplogReader* reader, const HostAndPort& host, const OID& myRID) {
-    if (reader->conn()) {
-        return true;
-    }
-
-    if (!reader->connect(host)) {
-        return false;
-    }
-
-    if (_doHandshake && !replHandshake(reader->conn(), myRID)) {
-        return false;
-    }
-
-    return true;
-}
-
-
-void ReplSource::forceResync(OperationContext* opCtx, const char* requester) {
-    BSONObj info;
-    {
-        // This is always a GlobalWrite lock (so no ns/db used from the context)
-        invariant(opCtx->lockState()->isW());
-        Lock::TempRelease tempRelease(opCtx->lockState());
-
-        if (!_connect(&oplogReader,
-                      HostAndPort(hostName),
-                      ReplicationCoordinator::get(opCtx)->getMyRID())) {
-            msgasserted(14051, "unable to connect to resync");
-        }
-        bool ok = oplogReader.conn()->runCommand(
-            "admin", BSON("listDatabases" << 1), info, QueryOption_SlaveOk);
-        massert(10385, "Unable to get database list", ok);
-    }
-
-    BSONObjIterator i(info.getField("databases").embeddedObject());
-    while (i.moreWithEOO()) {
-        BSONElement e = i.next();
-        if (e.eoo())
-            break;
-        std::string name = e.embeddedObject().getField("name").valuestr();
-        if (!e.embeddedObject().getBoolField("empty")) {
-            if (name != "local") {
-                if (only.empty() || only == name) {
-                    resyncDrop(opCtx, name);
-                }
-            }
-        }
-    }
-    syncedTo = Timestamp();
-    addDbNextPass.clear();
-    save(opCtx);
-}
-
-Status ReplSource::_updateIfDoneWithInitialSync(OperationContext* opCtx) {
-    const auto usedToDoHandshake = _doHandshake;
-    if (!usedToDoHandshake && addDbNextPass.empty() && incompleteCloneDbs.empty()) {
-        _doHandshake = true;
-        oplogReader.resetConnection();
-        const auto myRID = ReplicationCoordinator::get(opCtx)->getMyRID();
-        if (!_connect(&oplogReader, HostAndPort{hostName}, myRID)) {
-            return {ErrorCodes::MasterSlaveConnectionFailure,
-                    str::stream() << "could not connect to " << hostName << " with rid: "
-                                  << myRID.toString()};
-        } else {
-            return {ErrorCodes::Interrupted, "Initial Sync is done."};
-        }
-    }
-    return Status::OK();
-}
-
-void ReplSource::resyncDrop(OperationContext* opCtx, const std::string& dbName) {
-    log() << "resync: dropping database " << dbName;
-    invariant(opCtx->lockState()->isW());
-
-    Database* const db = dbHolder().get(opCtx, dbName);
-    if (!db) {
-        log() << "resync: dropping database " << dbName
-              << " - database does not exist. nothing to do.";
-        return;
-    }
-    Database::dropDatabase(opCtx, db);
-}
-
-/* grab initial copy of a database from the master */
-void ReplSource::resync(OperationContext* opCtx, const std::string& dbName) {
-    const std::string db(dbName);  // need local copy of the name, we're dropping the original
-    resyncDrop(opCtx, db);
-
-    {
-        log() << "resync: cloning database " << db << " to get an initial copy" << endl;
-        ReplInfo r("resync: cloning a database");
-
-        CloneOptions cloneOptions;
-        cloneOptions.fromDB = db;
-        cloneOptions.slaveOk = true;
-        cloneOptions.useReplAuth = true;
-        cloneOptions.snapshot = true;
-
-        Cloner cloner;
-        Status status = cloner.copyDb(opCtx, db, hostName.c_str(), cloneOptions, NULL);
-
-        if (!status.isOK()) {
-            if (status.code() == ErrorCodes::DatabaseDifferCase) {
-                resyncDrop(opCtx, db);
-                log() << "resync: database " << db
-                      << " not valid on the master due to a name conflict, dropping.";
-                return;
-            } else {
-                log() << "resync of " << db << " from " << hostName
-                      << " failed due to: " << redact(status);
-                throw SyncException();
-            }
-        }
-    }
-
-    log() << "resync: done with initial clone for db: " << db << endl;
-}
-
-static DatabaseIgnorer ___databaseIgnorer;
-
-void DatabaseIgnorer::doIgnoreUntilAfter(const std::string& db, const Timestamp& futureOplogTime) {
-    if (futureOplogTime > _ignores[db]) {
-        _ignores[db] = futureOplogTime;
-    }
-}
-
-bool DatabaseIgnorer::ignoreAt(const std::string& db, const Timestamp& currentOplogTime) {
-    if (_ignores[db].isNull()) {
-        return false;
-    }
-    if (_ignores[db] >= currentOplogTime) {
-        return true;
-    } else {
-        // The ignore state has expired, so clear it.
-        _ignores.erase(db);
-        return false;
-    }
-}
-
-bool ReplSource::handleDuplicateDbName(OperationContext* opCtx,
-                                       const BSONObj& op,
-                                       const char* ns,
-                                       const char* db) {
-    // We are already locked at this point
-    if (dbHolder().get(opCtx, ns) != NULL) {
-        // Database is already present.
-        return true;
-    }
-    BSONElement ts = op.getField("ts");
-    if ((ts.type() == Date || ts.type() == bsonTimestamp) &&
-        ___databaseIgnorer.ignoreAt(db, ts.timestamp())) {
-        // Database is ignored due to a previous indication that it is
-        // missing from master after optime "ts".
-        return false;
-    }
-    if (dbHolder().getNamesWithConflictingCasing(db).empty()) {
-        // No duplicate database names are present.
-        return true;
-    }
-
-    Timestamp lastTime;
-    bool dbOk = false;
-    {
-        // This is always a GlobalWrite lock (so no ns/db used from the context)
-        invariant(opCtx->lockState()->isW());
-        Lock::TempRelease tempRelease(opCtx->lockState());
-
-        // We always log an operation after executing it (never before), so
-        // a database list will always be valid as of an oplog entry generated
-        // before it was retrieved.
-
-        BSONObj last =
-            oplogReader.findOne(this->ns().c_str(), Query().sort(BSON("$natural" << -1)));
-        if (!last.isEmpty()) {
-            BSONElement ts = last.getField("ts");
-            massert(14032,
-                    "Invalid 'ts' in remote log",
-                    ts.type() == Date || ts.type() == bsonTimestamp);
-            lastTime = Timestamp(ts.date());
-        }
-
-        BSONObj info;
-        bool ok = oplogReader.conn()->runCommand("admin", BSON("listDatabases" << 1), info);
-        massert(14033, "Unable to get database list", ok);
-        BSONObjIterator i(info.getField("databases").embeddedObject());
-        while (i.more()) {
-            BSONElement e = i.next();
-
-            const char* name = e.embeddedObject().getField("name").valuestr();
-            if (strcasecmp(name, db) != 0)
-                continue;
-
-            if (strcmp(name, db) == 0) {
-                // The db exists on master, still need to check that no conflicts exist there.
-                dbOk = true;
-                continue;
-            }
-
-            // The master has a db name that conflicts with the requested name.
-            dbOk = false;
-            break;
-        }
-    }
-
-    if (!dbOk) {
-        ___databaseIgnorer.doIgnoreUntilAfter(db, lastTime);
-        incompleteCloneDbs.erase(db);
-        addDbNextPass.erase(db);
-        return false;
-    }
-
-    // Check for duplicates again, since we released the lock above.
-    auto duplicates = dbHolder().getNamesWithConflictingCasing(db);
-
-    // The database is present on the master and no conflicting databases
-    // are present on the master.  Drop any local conflicts.
-    for (set<std::string>::const_iterator i = duplicates.begin(); i != duplicates.end(); ++i) {
-        ___databaseIgnorer.doIgnoreUntilAfter(*i, lastTime);
-        incompleteCloneDbs.erase(*i);
-        addDbNextPass.erase(*i);
-
-        AutoGetDb autoDb(opCtx, *i, MODE_X);
-        Database::dropDatabase(opCtx, autoDb.getDb());
-    }
-
-    massert(14034,
-            "Duplicate database names present after attempting to delete duplicates",
-            dbHolder().getNamesWithConflictingCasing(db).empty());
-    return true;
-}
-
-void ReplSource::applyCommand(OperationContext* opCtx, const BSONObj& op) {
-    try {
-        Status status = applyCommand_inlock(opCtx, op, OplogApplication::Mode::kMasterSlave);
-        uassert(28639, "Failure applying initial sync command", status.isOK());
-    } catch (AssertionException& e) {
-        log() << "sync: caught user assertion " << redact(e) << " while applying op: " << redact(op)
-              << endl;
-        ;
-    } catch (DBException& e) {
-        log() << "sync: caught db exception " << redact(e) << " while applying op: " << redact(op)
-              << endl;
-        ;
-    }
-}
-
-void ReplSource::applyOperation(OperationContext* opCtx, Database* db, const BSONObj& op) {
-    try {
-        Status status =
-            applyOperation_inlock(opCtx, db, op, false, OplogApplication::Mode::kMasterSlave);
-        if (!status.isOK()) {
-            uassert(15914,
-                    "Failure applying initial sync operation",
-                    status == ErrorCodes::UpdateOperationFailed);
-
-            // In initial sync, update operations can cause documents to be missed during
-            // collection cloning. As a result, it is possible that a document that we need to
-            // update is not present locally. In that case we fetch the document from the
-            // sync source.
-            SyncTail sync(nullptr, SyncTail::MultiSyncApplyFunc(), nullptr);
-            sync.setHostname(hostName);
-            OplogEntry oplogEntry(op);
-            sync.fetchAndInsertMissingDocument(opCtx, oplogEntry);
-        }
-    } catch (AssertionException& e) {
-        log() << "sync: caught user assertion " << redact(e) << " while applying op: " << redact(op)
-              << endl;
-        ;
-    } catch (DBException& e) {
-        log() << "sync: caught db exception " << redact(e) << " while applying op: " << redact(op)
-              << endl;
-        ;
-    }
-}
-
-/* local.$oplog.main is of the form:
-     { ts: ..., op: <optype>, ns: ..., o: <obj> , o2: <extraobj>, b: <boolflag> }
-     ...
-   see logOp() comments.
-
-   @param alreadyLocked caller already put us in write lock if true
-*/
-void ReplSource::_sync_pullOpLog_applyOperation(OperationContext* opCtx,
-                                                BSONObj& op,
-                                                bool alreadyLocked) {
-    LOG(6) << "processing op: " << redact(op) << endl;
-
-    if (op.getStringField("op")[0] == 'n')
-        return;
-
-    const char* ns = op.getStringField("ns");
-    const auto dbName = nsToDatabaseSubstring(ns).toString();
-
-    if (*ns == '.') {
-        log() << "skipping bad op in oplog: " << redact(op) << endl;
-        return;
-    } else if (*ns == 0) {
-        /*if( op.getStringField("op")[0] != 'n' )*/ {
-            log() << "halting replication, bad op in oplog:\n  " << redact(op) << endl;
-            replAllDead = "bad object in oplog";
-            throw SyncException();
-        }
-        // ns = "local.system.x";
-        // nsToDatabase(ns, clientName);
-    }
-
-    if (!only.empty() && only != dbName)
-        return;
-
-    // Push the CurOp stack for "opCtx" so each individual oplog entry application is separately
-    // reported.
-    CurOp individualOp(opCtx);
-    UnreplicatedWritesBlock uwb(opCtx);
-    const ReplSettings& replSettings = ReplicationCoordinator::get(opCtx)->getSettings();
-    if (replSettings.getPretouch() &&
-        !alreadyLocked /*doesn't make sense if in write lock already*/) {
-        if (replSettings.getPretouch() > 1) {
-            /* note: this is bad - should be put in ReplSource.  but this is first test... */
-            static int countdown;
-            verify(countdown >= 0);
-            if (countdown > 0) {
-                countdown--;  // was pretouched on a prev pass
-            } else {
-                const int m = 4;
-                if (tp.get() == 0) {
-                    int nthr = min(8, replSettings.getPretouch());
-                    nthr = max(nthr, 1);
-                    ThreadPool::Options options;
-                    options.maxThreads = options.minThreads = std::size_t(nthr);
-                    options.poolName = "master_slave_pretouch";
-                    tp.reset(new ThreadPool(options));
-                }
-                vector<BSONObj> v;
-                oplogReader.peek(v, replSettings.getPretouch());
-                unsigned a = 0;
-                while (1) {
-                    if (a >= v.size())
-                        break;
-                    unsigned b = a + m - 1;  // v[a..b]
-                    if (b >= v.size())
-                        b = v.size() - 1;
-                    invariantOK(tp->schedule([&v, a, b] { pretouchN(v, a, b); }));
-                    DEV cout << "pretouch task: " << a << ".." << b << endl;
-                    a += m;
-                }
-                // we do one too...
-                pretouchOperation(opCtx, op);
-                tp->waitForIdle();
-                countdown = v.size();
-            }
-        } else {
-            pretouchOperation(opCtx, op);
-        }
-    }
-
-    unique_ptr<Lock::GlobalWrite> lk(alreadyLocked ? 0 : new Lock::GlobalWrite(opCtx));
-
-    if (replAllDead) {
-        // hmmm why is this check here and not at top of this function? does it get set between top
-        // and here?
-        log() << "replAllDead, throwing SyncException: " << replAllDead << endl;
-        throw SyncException();
-    }
-
-    if (!handleDuplicateDbName(opCtx, op, ns, dbName.c_str())) {
-        return;
-    }
-
-    // special case apply for commands to avoid implicit database creation
-    if (*op.getStringField("op") == 'c') {
-        applyCommand(opCtx, op);
-        return;
-    }
-
-    // This code executes on the slaves only, so it doesn't need to be sharding-aware since
-    // mongos will not send requests there. That's why the last argument is false (do not do
-    // version checking).
-    OldClientContext ctx(opCtx, ns, false);
-
-    bool empty = !ctx.db()->getDatabaseCatalogEntry()->hasUserData();
-    bool incompleteClone = incompleteCloneDbs.count(dbName) != 0;
-
-    LOG(6) << "ns: " << ns << ", justCreated: " << ctx.justCreated() << ", empty: " << empty
-           << ", incompleteClone: " << incompleteClone << endl;
-
-    if (ctx.justCreated() || empty || incompleteClone) {
-        // we must add to incomplete list now that setClient has been called
-        incompleteCloneDbs.insert(dbName);
-        if (nClonedThisPass) {
-            /* we only clone one database per pass, even if a lot need done.  This helps us
-             avoid overflowing the master's transaction log by doing too much work before going
-             back to read more transactions. (Imagine a scenario of slave startup where we try to
-             clone 100 databases in one pass.)
-             */
-            addDbNextPass.insert(dbName);
-        } else {
-            if (incompleteClone) {
-                log() << "An earlier initial clone of '" << dbName
-                      << "' did not complete, now resyncing." << endl;
-            }
-            save(opCtx);
-            OldClientContext ctx(opCtx, ns, false);
-            nClonedThisPass++;
-            resync(opCtx, ctx.db()->name());
-            addDbNextPass.erase(dbName);
-            incompleteCloneDbs.erase(dbName);
-        }
-        save(opCtx);
-    } else {
-        applyOperation(opCtx, ctx.db(), op);
-        addDbNextPass.erase(dbName);
-    }
-}
-
-void ReplSource::syncToTailOfRemoteLog() {
-    std::string _ns = ns();
-    BSONObjBuilder b;
-    if (!only.empty()) {
-        b.appendRegex("ns", std::string("^") + pcrecpp::RE::QuoteMeta(only));
-    }
-    BSONObj last = oplogReader.findOne(_ns.c_str(), Query(b.done()).sort(BSON("$natural" << -1)));
-    if (!last.isEmpty()) {
-        BSONElement ts = last.getField("ts");
-        massert(10386,
-                "non Date ts found: " + last.toString(),
-                ts.type() == Date || ts.type() == bsonTimestamp);
-        syncedTo = Timestamp(ts.date());
-    }
-}
-
-AtomicInt32 replApplyBatchSize(1);
-
-class ReplApplyBatchSize
-    : public ExportedServerParameter<int, ServerParameterType::kStartupAndRuntime> {
-public:
-    ReplApplyBatchSize()
-        : ExportedServerParameter<int, ServerParameterType::kStartupAndRuntime>(
-              ServerParameterSet::getGlobal(), "replApplyBatchSize", &replApplyBatchSize) {}
-
-    virtual Status validate(const int& potentialNewValue) {
-        if (potentialNewValue < 1 || potentialNewValue > 1024) {
-            return Status(ErrorCodes::BadValue, "replApplyBatchSize has to be >= 1 and <= 1024");
-        }
-
-        const ReplSettings& replSettings =
-            ReplicationCoordinator::get(getGlobalServiceContext())->getSettings();
-        if (replSettings.getSlaveDelaySecs() != Seconds(0) && potentialNewValue > 1) {
-            return Status(ErrorCodes::BadValue, "can't use a batch size > 1 with slavedelay");
-        }
-
-        if (!replSettings.isSlave()) {
-            return Status(ErrorCodes::BadValue,
-                          "can't set replApplyBatchSize on a non-slave machine");
-        }
-
-        return Status::OK();
-    }
-} replApplyBatchSizeServerParameter;
-
-/* slave: pull some data from the master's oplog
-   note: not yet in db mutex at this point.
-   @return -1 error
-           0 ok, don't sleep
-           1 ok, sleep
-*/
-int ReplSource::_sync_pullOpLog(OperationContext* opCtx, int& nApplied) {
-    int okResultCode = restartSyncAfterSleep;
-    std::string ns = std::string("local.oplog.$") + sourceName();
-    LOG(2) << "sync_pullOpLog " << ns << " syncedTo:" << syncedTo << '\n';
-
-    bool tailing = true;
-    oplogReader.tailCheck();
-
-    // Due to the lack of exception handlers, don't allow lock interrupts.
-    UninterruptibleLockGuard noInterrupt(opCtx->lockState());
-
-    bool initial = syncedTo.isNull();
-
-    if (!oplogReader.haveCursor() || initial) {
-        if (initial) {
-            // Important to grab last oplog timestamp before listing databases.
-            syncToTailOfRemoteLog();
-            BSONObj info;
-            bool ok = oplogReader.conn()->runCommand("admin", BSON("listDatabases" << 1), info);
-            massert(10389, "Unable to get database list", ok);
-            BSONObjIterator i(info.getField("databases").embeddedObject());
-            while (i.moreWithEOO()) {
-                BSONElement e = i.next();
-                if (e.eoo())
-                    break;
-                std::string name = e.embeddedObject().getField("name").valuestr();
-                if (!e.embeddedObject().getBoolField("empty")) {
-                    if (name != "local") {
-                        if (only.empty() || only == name) {
-                            LOG(2) << "adding to 'addDbNextPass': " << name << endl;
-                            addDbNextPass.insert(name);
-                        }
-                    }
-                }
-            }
-            // obviously global isn't ideal, but non-repl set is old so
-            // keeping it simple
-            Lock::GlobalWrite lk(opCtx);
-            save(opCtx);
-        }
-
-        BSONObjBuilder gte;
-        gte.append("$gte", syncedTo);
-        BSONObjBuilder query;
-        query.append("ts", gte.done());
-        if (!only.empty()) {
-            // note we may here skip a LOT of data table scanning, a lot of work for the master.
-            // maybe append "\\." here?
-            query.appendRegex("ns", std::string("^") + pcrecpp::RE::QuoteMeta(only));
-        }
-        BSONObj queryObj = query.done();
-        // e.g. queryObj = { ts: { $gte: syncedTo } }
-
-        oplogReader.tailingQuery(ns.c_str(), queryObj);
-        tailing = false;
-    } else {
-        LOG(2) << "tailing=true\n";
-    }
-
-    if (!oplogReader.haveCursor()) {
-        log() << "dbclient::query returns null (conn closed?)" << endl;
-        oplogReader.resetConnection();
-        return forceReconnect;
-    }
-
-    // show any deferred database creates from a previous pass
-    {
-        set<std::string>::iterator i = addDbNextPass.begin();
-        if (i != addDbNextPass.end()) {
-            BSONObjBuilder b;
-            b.append("ns", *i + '.');
-            b.append("op", "db");
-            BSONObj op = b.done();
-            _sync_pullOpLog_applyOperation(opCtx, op, false);
-        }
-    }
-
-    auto status = _updateIfDoneWithInitialSync(opCtx);
-    if (!status.isOK()) {
-        switch (status.code()) {
-            case ErrorCodes::Interrupted: {
-                return restartSync;  // don't sleep;
-            }
-            default: {
-                error() << redact(status);
-                return forceReconnect;  // causes reconnect.
-            }
-        }
-    }
-
-    if (!oplogReader.more()) {
-        if (tailing) {
-            LOG(2) << "tailing & no new activity\n";
-            okResultCode = restartSync;  // don't sleep
-
-        } else {
-            log() << ns << " oplog is empty" << endl;
-        }
-        {
-            Lock::GlobalWrite lk(opCtx);
-            save(opCtx);
-        }
-        return okResultCode;
-    }
-
-    Timestamp nextOpTime;
-    {
-        BSONObj op = oplogReader.nextSafe();
-        BSONElement ts = op.getField("ts");
-        if (ts.type() != Date && ts.type() != bsonTimestamp) {
-            std::string err = op.getStringField("$err");
-            if (!err.empty()) {
-                // 13051 is "tailable cursor requested on non capped collection"
-                if (op.getIntField("code") == 13051) {
-                    log() << "trying to slave off of a non-master" << '\n';
-                    massert(13344, "trying to slave off of a non-master", false);
-                } else {
-                    error() << "$err reading remote oplog: " + redact(err) << '\n';
-                    massert(10390, "got $err reading remote oplog", false);
-                }
-            } else {
-                error() << "bad object read from remote oplog: " << redact(op) << '\n';
-                massert(10391, "bad object read from remote oplog", false);
-            }
-        }
-
-        nextOpTime = Timestamp(ts.date());
-        LOG(2) << "first op time received: " << nextOpTime.toString() << '\n';
-        if (initial) {
-            LOG(1) << "initial run\n";
-        }
-        if (tailing) {
-            if (!(syncedTo < nextOpTime)) {
-                warning() << "ASSERTION failed : syncedTo < nextOpTime" << endl;
-                log() << "syncTo:     " << syncedTo << endl;
-                log() << "nextOpTime: " << nextOpTime << endl;
-                verify(false);
-            }
-            oplogReader.putBack(op);          // op will be processed in the loop below
-            nextOpTime = Timestamp();         // will reread the op below
-        } else if (nextOpTime != syncedTo) {  // didn't get what we queried for - error
-            log() << "nextOpTime " << nextOpTime << ' ' << ((nextOpTime < syncedTo) ? "<??" : ">")
-                  << " syncedTo " << syncedTo << '\n'
-                  << "time diff: " << (nextOpTime.getSecs() - syncedTo.getSecs()) << "sec\n"
-                  << "tailing: " << tailing << '\n'
-                  << "data too stale, halting replication" << endl;
-            replInfo = replAllDead = "data too stale halted replication";
-            verify(syncedTo < nextOpTime);
-            throw SyncException();
-        } else {
-            /* t == syncedTo, so the first op was applied previously or it is the first op of
-             * initial query and need not be applied. */
-        }
-    }
-
-    // apply operations
-    {
-        int n = 0;
-        time_t saveLast = time(0);
-        while (1) {
-            // we need "&& n" to assure we actually process at least one op to get a sync
-            // point recorded in the first place.
-            const bool moreInitialSyncsPending = !addDbNextPass.empty() && n;
-
-            if (moreInitialSyncsPending || !oplogReader.more()) {
-                Lock::GlobalWrite lk(opCtx);
-
-                if (tailing) {
-                    okResultCode = restartSync;  // don't sleep
-                }
-
-                syncedTo = nextOpTime;
-                save(opCtx);  // note how far we are synced up to now
-                nApplied = n;
-                break;
-            }
-
-            OCCASIONALLY if (n > 0 && (n > 100000 || time(0) - saveLast > 60)) {
-                // periodically note our progress, in case we are doing a lot of work and crash
-                Lock::GlobalWrite lk(opCtx);
-                syncedTo = nextOpTime;
-                // can't update local log ts since there are pending operations from our peer
-                save(opCtx);
-                log() << "checkpoint applied " << n << " operations" << endl;
-                log() << "syncedTo: " << syncedTo << endl;
-                saveLast = time(0);
-                n = 0;
-            }
-
-            BSONObj op = oplogReader.nextSafe();
-
-            int b = replApplyBatchSize.load();
-            bool justOne = b == 1;
-            unique_ptr<Lock::GlobalWrite> lk(justOne ? 0 : new Lock::GlobalWrite(opCtx));
-            while (1) {
-                BSONElement ts = op.getField("ts");
-                if (!(ts.type() == Date || ts.type() == bsonTimestamp)) {
-                    log() << "sync error: problem querying remote oplog record" << endl;
-                    log() << "op: " << redact(op) << endl;
-                    log() << "halting replication" << endl;
-                    replInfo = replAllDead = "sync error: no ts found querying remote oplog record";
-                    throw SyncException();
-                }
-                Timestamp last = nextOpTime;
-                nextOpTime = Timestamp(ts.date());
-                if (!(last < nextOpTime)) {
-                    log() << "sync error: last applied optime at slave >= nextOpTime from master"
-                          << endl;
-                    log() << " last:       " << last << endl;
-                    log() << " nextOpTime: " << nextOpTime << endl;
-                    log() << " halting replication" << endl;
-                    replInfo = replAllDead = "sync error last >= nextOpTime";
-                    uassert(
-                        10123,
-                        "replication error last applied optime at slave >= nextOpTime from master",
-                        false);
-                }
-                const ReplSettings& replSettings =
-                    ReplicationCoordinator::get(opCtx)->getSettings();
-                if (replSettings.getSlaveDelaySecs() != Seconds(0) &&
-                    (Seconds(time(0)) <
-                     Seconds(nextOpTime.getSecs()) + replSettings.getSlaveDelaySecs())) {
-                    verify(justOne);
-                    oplogReader.putBack(op);
-                    _sleepAdviceTime = nextOpTime.getSecs() +
-                        durationCount<Seconds>(replSettings.getSlaveDelaySecs()) + 1;
-                    Lock::GlobalWrite lk(opCtx);
-                    if (n > 0) {
-                        syncedTo = last;
-                        save(opCtx);
-                    }
-                    log() << "applied " << n << " operations" << endl;
-                    log() << "syncedTo: " << syncedTo << endl;
-                    log() << "waiting until: " << _sleepAdviceTime << " to continue" << endl;
-                    return okResultCode;
-                }
-
-                _sync_pullOpLog_applyOperation(opCtx, op, !justOne);
-                n++;
-
-                if (--b == 0)
-                    break;
-                // if to here, we are doing mulpile applications in a singel write lock acquisition
-                if (!oplogReader.moreInCurrentBatch()) {
-                    // break if no more in batch so we release lock while reading from the master
-                    break;
-                }
-                op = oplogReader.nextSafe();
-            }
-        }
-    }
-
-    return okResultCode;
-}
-
-
-/* note: not yet in mutex at this point.
-   returns >= 0 if ok.  return -1 if you want to reconnect.
-   return value of zero indicates no sleep necessary before next call
-*/
-int ReplSource::sync(OperationContext* opCtx, int& nApplied) {
-    _sleepAdviceTime = 0;
-    ReplInfo r("sync");
-    if (!serverGlobalParams.quiet.load()) {
-        LogstreamBuilder l = log();
-        l << "syncing from ";
-        if (sourceName() != "main") {
-            l << "source:" << sourceName() << ' ';
-        }
-        l << "host:" << hostName << endl;
-    }
-    nClonedThisPass = 0;
-
-    // FIXME Handle cases where this db isn't on default port, or default port is spec'd in
-    // hostName.
-    if ((std::string("localhost") == hostName || std::string("127.0.0.1") == hostName) &&
-        serverGlobalParams.port == ServerGlobalParams::DefaultDBPort) {
-        log() << "can't sync from self (localhost). sources configuration may be wrong." << endl;
-        sleepsecs(5);
-        return -1;
-    }
-
-    if (!_connect(
-            &oplogReader, HostAndPort(hostName), ReplicationCoordinator::get(opCtx)->getMyRID())) {
-        LOG(4) << "can't connect to sync source" << endl;
-        return -1;
-    }
-
-    return _sync_pullOpLog(opCtx, nApplied);
-}
-
-/* --------------------------------------------------------------*/
-
-static bool _replMainStarted = false;
-
-/*
-TODO:
-_ source has autoptr to the cursor
-_ reuse that cursor when we can
-*/
-
-/* returns: # of seconds to sleep before next pass
-            0 = no sleep recommended
-            1 = special sentinel indicating adaptive sleep recommended
-*/
-int _replMain(OperationContext* opCtx, ReplSource::SourceVector& sources, int& nApplied) {
-    {
-        ReplInfo r("replMain load sources");
-        Lock::GlobalWrite lk(opCtx);
-        ReplSource::loadAll(opCtx, sources);
-
-        // only need this param for initial reset
-        _replMainStarted = true;
-    }
-
-    if (sources.empty()) {
-        /* replication is not configured yet (for --slave) in local.sources.  Poll for config it
-        every 20 seconds.
-        */
-        log() << "no source given, add a master to local.sources to start replication" << endl;
-        return 20;
-    }
-
-    int sleepAdvice = 1;
-    for (ReplSource::SourceVector::iterator i = sources.begin(); i != sources.end(); i++) {
-        ReplSource* s = i->get();
-        int res = forceReconnect;
-        try {
-            res = s->sync(opCtx, nApplied);
-            bool moreToSync = s->haveMoreDbsToSync();
-            if (res < 0) {
-                sleepAdvice = 3;
-            } else if (moreToSync) {
-                sleepAdvice = 0;
-            } else if (s->sleepAdvice()) {
-                sleepAdvice = s->sleepAdvice();
-            } else
-                sleepAdvice = res;
-        } catch (const SyncException&) {
-            log() << "caught SyncException" << endl;
-            return 10;
-        } catch (const DBException& e) {
-            log() << "DBException " << redact(e) << endl;
-            replInfo = "replMain caught DBException";
-        } catch (const std::exception& e) {
-            log() << "std::exception " << redact(e.what()) << endl;
-            replInfo = "replMain caught std::exception";
-        } catch (...) {
-            log() << "unexpected exception during replication.  replication will halt" << endl;
-            replAllDead = "caught unexpected exception during replication";
-        }
-        if (res < 0)
-            s->oplogReader.resetConnection();
-    }
-    return sleepAdvice;
-}
-
-static void replMain(OperationContext* opCtx) {
-    ReplSource::SourceVector sources;
-    while (1) {
-        auto s = restartSync;
-        {
-            Lock::GlobalWrite lk(opCtx);
-            if (replAllDead) {
-                // throttledForceResyncDead can throw
-                if (!ReplicationCoordinator::get(opCtx)->getSettings().isAutoResyncEnabled() ||
-                    !ReplSource::throttledForceResyncDead(opCtx, "auto")) {
-                    log() << "all sources dead: " << replAllDead << ", sleeping for 5 seconds"
-                          << endl;
-                    break;
-                }
-            }
-
-            // i.e., there is only one sync thread running. we will want to change/fix this.
-            invariant(syncing.swap(1) == 0);
-        }
-
-        try {
-            int nApplied = 0;
-            s = _replMain(opCtx, sources, nApplied);
-            if (s == restartSyncAfterSleep) {
-                if (nApplied == 0)
-                    s = 2;
-                else if (nApplied > 100) {
-                    // sleep very little - just enough that we aren't truly hammering master
-                    sleepmillis(75);
-                    s = restartSync;
-                }
-            }
-        } catch (...) {
-            log() << "caught exception in _replMain" << endl;
-            s = 4;
-        }
-
-        {
-            Lock::GlobalWrite lk(opCtx);
-            invariant(syncing.swap(0) == 1);
-        }
-
-        if (relinquishSyncingSome.load()) {
-            relinquishSyncingSome.store(0);
-            s = restartSyncAfterSleep;  // sleep before going back in to syncing=1
-        }
-
-        if (s) {
-            stringstream ss;
-            ss << "sleep " << s << " sec before next pass";
-            std::string msg = ss.str();
-            if (!serverGlobalParams.quiet.load())
-                log() << msg << endl;
-            ReplInfo r(msg.c_str());
-            sleepsecs(s);
-        }
-    }
-}
-
-static void replMasterThread() {
-    sleepsecs(4);
-    Client::initThread("replmaster");
-    int toSleep = 10;
-    while (1) {
-        sleepsecs(toSleep);
-
-        // Write a keep-alive like entry to the log. This will make things like
-        // printReplicationStatus() and printSlaveReplicationStatus() stay up-to-date even
-        // when things are idle.
-        const ServiceContext::UniqueOperationContext opCtxPtr = cc().makeOperationContext();
-        OperationContext& opCtx = *opCtxPtr;
-        AuthorizationSession::get(opCtx.getClient())->grantInternalAuthorization();
-
-        UninterruptibleLockGuard noInterrupt(opCtx.lockState());
-        Lock::GlobalWrite globalWrite(&opCtx, Date_t::now() + Milliseconds(1));
-        if (globalWrite.isLocked()) {
-            toSleep = 10;
-
-            try {
-                WriteUnitOfWork wuow(&opCtx);
-                getGlobalServiceContext()->getOpObserver()->onOpMessage(&opCtx, BSONObj());
-                wuow.commit();
-            } catch (...) {
-                log() << "caught exception in replMasterThread()" << endl;
-            }
-        } else {
-            LOG(5) << "couldn't logKeepalive" << endl;
-            toSleep = 1;
-        }
-    }
-}
-
-static void replSlaveThread() {
-    sleepsecs(1);
-    Client::initThread("replslave");
-
-    const ServiceContext::UniqueOperationContext opCtxPtr = cc().makeOperationContext();
-    OperationContext& opCtx = *opCtxPtr;
-    AuthorizationSession::get(opCtx.getClient())->grantInternalAuthorization();
-    DisableDocumentValidation validationDisabler(&opCtx);
-
-    while (1) {
-        try {
-            replMain(&opCtx);
-            sleepsecs(5);
-        } catch (AssertionException&) {
-            ReplInfo r("Assertion in replSlaveThread(): sleeping 5 minutes before retry");
-            log() << "Assertion in replSlaveThread(): sleeping 5 minutes before retry" << endl;
-            sleepsecs(300);
-        } catch (DBException& e) {
-            log() << "exception in replSlaveThread(): " << e.what()
-                  << ", sleeping 5 minutes before retry" << endl;
-            sleepsecs(300);
-        } catch (...) {
-            log() << "error in replSlaveThread(): sleeping 5 minutes before retry" << endl;
-            sleepsecs(300);
-        }
-    }
-}
-
-void startMasterSlave(OperationContext* opCtx) {
-    const ReplSettings& replSettings = ReplicationCoordinator::get(opCtx)->getSettings();
-    if (!replSettings.isSlave() && !replSettings.isMaster())
-        return;
-
-    AuthorizationSession::get(opCtx->getClient())->grantInternalAuthorization();
-
-    {
-        ReplSource temp(opCtx);  // Ensures local.me is populated
-    }
-
-    if (replSettings.isSlave()) {
-        LOG(1) << "slave=true" << endl;
-        stdx::thread repl_thread(replSlaveThread);
-        repl_thread.detach();
-    }
-
-    if (replSettings.isMaster()) {
-        LOG(1) << "master=true" << endl;
-        createOplog(opCtx);
-        stdx::thread t(replMasterThread);
-        t.detach();
-    }
-
-    if (replSettings.isFastSyncEnabled()) {
-        while (!_replMainStarted)  // don't allow writes until we've set up from log
-            sleepmillis(50);
-    }
-}
-int _dummy_z;
-
-void pretouchN(const std::vector<BSONObj>& v, unsigned a, unsigned b) {
-    Client::initThreadIfNotAlready("pretouchN");
-
-    const ServiceContext::UniqueOperationContext opCtxPtr = cc().makeOperationContext();
-    OperationContext& opCtx = *opCtxPtr;  // XXX
-    Lock::GlobalRead lk(&opCtx);
-
-    for (unsigned i = a; i <= b; i++) {
-        const BSONObj& op = v[i];
-        const char* which = "o";
-        const char* opType = op.getStringField("op");
-        if (*opType == 'i')
-            ;
-        else if (*opType == 'u')
-            which = "o2";
-        else
-            continue;
-        /* todo : other operations */
-
-        try {
-            BSONObj o = op.getObjectField(which);
-            BSONElement _id;
-            if (o.getObjectID(_id)) {
-                const char* ns = op.getStringField("ns");
-                BSONObjBuilder b;
-                b.append(_id);
-                BSONObj result;
-                OldClientContext ctx(&opCtx, ns, false);
-                if (Helpers::findById(&opCtx, ctx.db(), ns, b.done(), result))
-                    _dummy_z += result.objsize();  // touch
-            }
-        } catch (DBException& e) {
-            log() << "ignoring assertion in pretouchN() " << a << ' ' << b << ' ' << i << ' '
-                  << redact(e) << endl;
-        }
-    }
-}
-
-void pretouchOperation(OperationContext* opCtx, const BSONObj& op) {
-    if (opCtx->lockState()->isWriteLocked()) {
-        // no point pretouching if write locked. not sure if this will ever fire, but just in case.
-        return;
-    }
-
-    const char* which = "o";
-    const char* opType = op.getStringField("op");
-    if (*opType == 'i')
-        ;
-    else if (*opType == 'u')
-        which = "o2";
-    else
-        return;
-    /* todo : other operations */
-
-    try {
-        BSONObj o = op.getObjectField(which);
-        BSONElement _id;
-        if (o.getObjectID(_id)) {
-            const char* ns = op.getStringField("ns");
-            BSONObjBuilder b;
-            b.append(_id);
-            BSONObj result;
-            AutoGetCollectionForReadCommand ctx(opCtx, NamespaceString(ns));
-            if (Helpers::findById(opCtx, ctx.getDb(), ns, b.done(), result)) {
-                _dummy_z += result.objsize();  // touch
-            }
-        }
-    } catch (DBException&) {
-        log() << "ignoring assertion in pretouchOperation()" << endl;
-    }
-}
-
-}  // namespace repl
-}  // namespace mongo
diff --git a/src/mongo/db/repl/master_slave.h b/src/mongo/db/repl/master_slave.h
deleted file mode 100644
index 3c96386080f..00000000000
--- a/src/mongo/db/repl/master_slave.h
+++ /dev/null
@@ -1,219 +0,0 @@
-/**
-*    Copyright (C) 2008 10gen Inc.
-*
-*    This program is free software: you can redistribute it and/or  modify
-*    it under the terms of the GNU Affero General Public License, version 3,
-*    as published by the Free Software Foundation.
-*
-*    This program is distributed in the hope that it will be useful,
-*    but WITHOUT ANY WARRANTY; without even the implied warranty of
-*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-*    GNU Affero General Public License for more details.
-*
-*    You should have received a copy of the GNU Affero General Public License
-*    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*
-*    As a special exception, the copyright holders give permission to link the
-*    code of portions of this program with the OpenSSL library under certain
-*    conditions as described in each individual source file and distribute
-*    linked combinations including the program with the OpenSSL library. You
-*    must comply with the GNU Affero General Public License in all respects for
-*    all of the code used other than as permitted herein. If you modify file(s)
-*    with this exception, you may extend this exception to your version of the
-*    file(s), but you are not obligated to do so. If you do not wish to do so,
-*    delete this exception statement from your version. If you delete this
-*    exception statement from all source files in the program, then also delete
-*    it in the license file.
-*/
-
-#pragma once
-
-#include "mongo/db/repl/oplogreader.h"
-#include "mongo/platform/atomic_word.h"
-#include "mongo/util/concurrency/thread_pool.h"
-
-/* replication data overview
-
-   at the slave:
-     local.sources { host: ..., source: ..., only: ..., syncedTo: ..., localLogTs: ...,
-                    dbsNextPass: { ... }, incompleteCloneDbs: { ... } }
-
-   at the master:
-     local.oplog.$<source>
-*/
-
-namespace mongo {
-
-class Database;
-class OperationContext;
-
-namespace repl {
-
-// Main entry point for master/slave at startup time.
-void startMasterSlave(OperationContext* opCtx);
-
-// externed for use with resync.cpp
-extern AtomicInt32 relinquishSyncingSome;
-extern AtomicInt32 syncing;
-
-extern const char* replInfo;
-
-/* A replication exception */
-class SyncException final : public DBException {
-public:
-    SyncException() : DBException(Status(ErrorCodes::Error(10001), "sync exception")) {}
-
-private:
-    void defineOnlyInFinalSubclassToPreventSlicing() final {}
-};
-
-/* A Source is a source from which we can pull (replicate) data.
-   stored in collection local.sources.
-
-   Can be a group of things to replicate for several databases.
-
-      { host: ..., source: ..., only: ..., syncedTo: ..., dbsNextPass: { ... },
-        incompleteCloneDbs: { ... } }
-
-   'source' defaults to 'main'; support for multiple source names is
-   not done (always use main for now).
-*/
-class ReplSource {
-    std::shared_ptr<ThreadPool> tp;
-
-    void resync(OperationContext* opCtx, const std::string& dbName);
-
-    /** @param alreadyLocked caller already put us in write lock if true */
-    void _sync_pullOpLog_applyOperation(OperationContext* opCtx, BSONObj& op, bool alreadyLocked);
-
-    /* pull some operations from the master's oplog, and apply them.
-       calls sync_pullOpLog_applyOperation
-    */
-    int _sync_pullOpLog(OperationContext* opCtx, int& nApplied);
-
-    /* we only clone one database per pass, even if a lot need done.  This helps us
-       avoid overflowing the master's transaction log by doing too much work before going
-       back to read more transactions. (Imagine a scenario of slave startup where we try to
-       clone 100 databases in one pass.)
-    */
-    std::set<std::string> addDbNextPass;
-
-    std::set<std::string> incompleteCloneDbs;
-
-    /// TODO(spencer): Remove this once the LegacyReplicationCoordinator is gone.
-    BSONObj _me;
-
-    /**
-     * Flag to control if a handshake is done on a connection or not. Default to false
-     * until all databases are cloned.
-     */
-    bool _doHandshake = false;
-
-    void resyncDrop(OperationContext* opCtx, const std::string& dbName);
-    // call without the db mutex
-    void syncToTailOfRemoteLog();
-    std::string ns() const {
-        return std::string("local.oplog.$") + sourceName();
-    }
-    unsigned _sleepAdviceTime;
-
-    /**
-     * If 'db' is a new database and its name would conflict with that of
-     * an existing database, synchronize these database names with the
-     * master.
-     * @return true iff an op with the specified ns may be applied.
-     */
-    bool handleDuplicateDbName(OperationContext* opCtx,
-                               const BSONObj& op,
-                               const char* ns,
-                               const char* db);
-
-    // populates _me so that it can be passed to oplogreader for handshakes
-    /// TODO(spencer): Remove this function once the LegacyReplicationCoordinator is gone.
-    void ensureMe(OperationContext* opCtx);
-
-    void forceResync(OperationContext* opCtx, const char* requester);
-
-    bool _connect(OplogReader* reader, const HostAndPort& host, const OID& myRID);
-
-    Status _updateIfDoneWithInitialSync(OperationContext* opCtx);
-
-public:
-    OplogReader oplogReader;
-
-    void applyCommand(OperationContext* opCtx, const BSONObj& op);
-    void applyOperation(OperationContext* opCtx, Database* db, const BSONObj& op);
-    std::string hostName;     // ip addr or hostname plus optionally, ":<port>"
-    std::string _sourceName;  // a logical source name.
-    std::string sourceName() const {
-        return _sourceName.empty() ? "main" : _sourceName;
-    }
-
-    // only a certain db. note that in the sources collection, this may not be changed once you
-    // start replicating.
-    std::string only;
-
-    /* the last time point we have already synced up to (in the remote/master's oplog). */
-    Timestamp syncedTo;
-
-    int nClonedThisPass;
-
-    typedef std::vector<std::shared_ptr<ReplSource>> SourceVector;
-    static void loadAll(OperationContext* opCtx, SourceVector&);
-
-    explicit ReplSource(OperationContext* opCtx, BSONObj);
-    // This is not the constructor you are looking for. Always prefer the version that takes
-    // a BSONObj.  This is public only as a hack so that the ReplicationCoordinator can find
-    // out the process's RID in master/slave setups.
-    ReplSource(OperationContext* opCtx);
-
-    /* -1 = error */
-    int sync(OperationContext* opCtx, int& nApplied);
-
-    void save(OperationContext* opCtx);  // write ourself to local.sources
-
-    // make a jsobj from our member fields of the form
-    //   { host: ..., source: ..., syncedTo: ... }
-    BSONObj jsobj();
-
-    bool operator==(const ReplSource& r) const {
-        return hostName == r.hostName && sourceName() == r.sourceName();
-    }
-    std::string toString() const {
-        return sourceName() + "@" + hostName;
-    }
-
-    bool haveMoreDbsToSync() const {
-        return !addDbNextPass.empty();
-    }
-    int sleepAdvice() const {
-        if (!_sleepAdviceTime)
-            return 0;
-        int wait = _sleepAdviceTime - unsigned(time(0));
-        return wait > 0 ? wait : 0;
-    }
-
-    static bool throttledForceResyncDead(OperationContext* opCtx, const char* requester);
-    static void forceResyncDead(OperationContext* opCtx, const char* requester);
-};
-
-/**
- * Helper class used to set and query an ignore state for a named database.
- * The ignore state will expire after a specified Timestamp.
- */
-class DatabaseIgnorer {
-public:
-    /** Indicate that operations for 'db' should be ignored until after 'futureOplogTime' */
-    void doIgnoreUntilAfter(const std::string& db, const Timestamp& futureOplogTime);
-    /**
-     * Query ignore state of 'db'; if 'currentOplogTime' is after the ignore
-     * limit, the ignore state will be cleared.
-     */
-    bool ignoreAt(const std::string& db, const Timestamp& currentOplogTime);
-
-private:
-    std::map<std::string, Timestamp> _ignores;
-};
-
-}  // namespace repl
-}  // namespace mongo
diff --git a/src/mongo/db/repl/mock_repl_coord_server_fixture.cpp b/src/mongo/db/repl/mock_repl_coord_server_fixture.cpp
index 95dd56ea92b..e173b709602 100644
--- a/src/mongo/db/repl/mock_repl_coord_server_fixture.cpp
+++ b/src/mongo/db/repl/mock_repl_coord_server_fixture.cpp
@@ -71,10 +71,11 @@ void MockReplCoordServerFixture::setUp() {
     repl::ReplSettings replSettings;
     replSettings.setReplSetString(
         ConnectionString::forReplicaSet("sessionTxnStateTest", {HostAndPort("a:1")}).toString());
-    replSettings.setMaster(true);
 
     repl::ReplicationCoordinator::set(
         service, stdx::make_unique<repl::ReplicationCoordinatorMock>(service, replSettings));
+    ASSERT_OK(
+        repl::ReplicationCoordinator::get(service)->setFollowerMode(repl::MemberState::RS_PRIMARY));
 
     // Note: internal code does not allow implicit creation of non-capped oplog collection.
     DBDirectClient client(opCtx());
diff --git a/src/mongo/db/repl/oplog.cpp b/src/mongo/db/repl/oplog.cpp
index bd7e730c7a0..eba01f1076c 100644
--- a/src/mongo/db/repl/oplog.cpp
+++ b/src/mongo/db/repl/oplog.cpp
@@ -917,7 +917,6 @@ std::map<std::string, ApplyOpMetadata> opsMap = {
 }  // namespace
 
 constexpr StringData OplogApplication::kInitialSyncOplogApplicationMode;
-constexpr StringData OplogApplication::kMasterSlaveOplogApplicationMode;
 constexpr StringData OplogApplication::kRecoveringOplogApplicationMode;
 constexpr StringData OplogApplication::kSecondaryOplogApplicationMode;
 constexpr StringData OplogApplication::kApplyOpsCmdOplogApplicationMode;
@@ -926,8 +925,6 @@ StringData OplogApplication::modeToString(OplogApplication::Mode mode) {
     switch (mode) {
         case OplogApplication::Mode::kInitialSync:
             return OplogApplication::kInitialSyncOplogApplicationMode;
-        case OplogApplication::Mode::kMasterSlave:
-            return OplogApplication::kMasterSlaveOplogApplicationMode;
         case OplogApplication::Mode::kRecovering:
             return OplogApplication::kRecoveringOplogApplicationMode;
         case OplogApplication::Mode::kSecondary:
@@ -941,8 +938,6 @@ StringData OplogApplication::modeToString(OplogApplication::Mode mode) {
 StatusWith<OplogApplication::Mode> OplogApplication::parseMode(const std::string& mode) {
     if (mode == OplogApplication::kInitialSyncOplogApplicationMode) {
         return OplogApplication::Mode::kInitialSync;
-    } else if (mode == OplogApplication::kMasterSlaveOplogApplicationMode) {
-        return OplogApplication::Mode::kMasterSlave;
     } else if (mode == OplogApplication::kRecoveringOplogApplicationMode) {
         return OplogApplication::Mode::kRecovering;
     } else if (mode == OplogApplication::kSecondaryOplogApplicationMode) {
diff --git a/src/mongo/db/repl/oplog.h b/src/mongo/db/repl/oplog.h
index f6ea00d0067..1120b96c152 100644
--- a/src/mongo/db/repl/oplog.h
+++ b/src/mongo/db/repl/oplog.h
@@ -183,7 +183,6 @@ std::pair<BSONObj, NamespaceString> prepForApplyOpsIndexInsert(const BSONElement
 class OplogApplication {
 public:
     static constexpr StringData kInitialSyncOplogApplicationMode = "InitialSync"_sd;
-    static constexpr StringData kMasterSlaveOplogApplicationMode = "MasterSlave"_sd;
     static constexpr StringData kRecoveringOplogApplicationMode = "Recovering"_sd;
     static constexpr StringData kSecondaryOplogApplicationMode = "Secondary"_sd;
     static constexpr StringData kApplyOpsCmdOplogApplicationMode = "ApplyOps"_sd;
@@ -192,9 +191,6 @@ public:
         // Used during the oplog application phase of the initial sync process.
         kInitialSync,
 
-        // Used when a slave is applying operations from a master node in master-slave.
-        kMasterSlave,
-
         // Used when we are applying oplog operations to recover the database state following an
         // unclean shutdown, or when we are recovering from the oplog after we rollback to a
         // checkpoint.
diff --git a/src/mongo/db/repl/repl_settings.cpp b/src/mongo/db/repl/repl_settings.cpp
index 5f73147ee47..3fb69df5d3d 100644
--- a/src/mongo/db/repl/repl_settings.cpp
+++ b/src/mongo/db/repl/repl_settings.cpp
@@ -28,11 +28,10 @@
 
 #define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplication
 
-#include "mongo/db/repl/repl_settings.h"
+#include "mongo/platform/basic.h"
 
-#include <string>
+#include "mongo/db/repl/repl_settings.h"
 
-#include "mongo/db/repl/bgsync.h"
 #include "mongo/util/log.h"
 
 namespace mongo {
@@ -52,42 +51,11 @@ bool ReplSettings::usingReplSets() const {
 /**
  * Getters
  */
-bool ReplSettings::isSlave() const {
-    return _slave;
-}
-
-bool ReplSettings::isMaster() const {
-    return _master;
-}
-
-bool ReplSettings::isFastSyncEnabled() const {
-    return _fastSyncEnabled;
-}
-
-bool ReplSettings::isAutoResyncEnabled() const {
-    return _autoResyncEnabled;
-}
-
-Seconds ReplSettings::getSlaveDelaySecs() const {
-    return _slaveDelaySecs;
-}
-
-int ReplSettings::getPretouch() const {
-    return _pretouch;
-}
 
 long long ReplSettings::getOplogSizeBytes() const {
     return _oplogSizeBytes;
 }
 
-std::string ReplSettings::getSource() const {
-    return _source;
-}
-
-std::string ReplSettings::getOnly() const {
-    return _only;
-}
-
 std::string ReplSettings::getReplSetString() const {
     return _replSetString;
 }
@@ -103,42 +71,11 @@ bool ReplSettings::isPrefetchIndexModeSet() const {
 /**
  * Setters
  */
-void ReplSettings::setSlave(bool slave) {
-    _slave = slave;
-}
-
-void ReplSettings::setMaster(bool master) {
-    _master = master;
-}
-
-void ReplSettings::setFastSyncEnabled(bool fastSyncEnabled) {
-    _fastSyncEnabled = fastSyncEnabled;
-}
-
-void ReplSettings::setAutoResyncEnabled(bool autoResyncEnabled) {
-    _autoResyncEnabled = autoResyncEnabled;
-}
-
-void ReplSettings::setSlaveDelaySecs(int slaveDelay) {
-    _slaveDelaySecs = Seconds(slaveDelay);
-}
-
-void ReplSettings::setPretouch(int pretouch) {
-    _pretouch = pretouch;
-}
 
 void ReplSettings::setOplogSizeBytes(long long oplogSizeBytes) {
     _oplogSizeBytes = oplogSizeBytes;
 }
 
-void ReplSettings::setSource(std::string source) {
-    _source = source;
-}
-
-void ReplSettings::setOnly(std::string only) {
-    _only = only;
-}
-
 void ReplSettings::setReplSetString(std::string replSetString) {
     _replSetString = replSetString;
 }
diff --git a/src/mongo/db/repl/repl_settings.h b/src/mongo/db/repl/repl_settings.h
index ce804fb3502..1a74414dade 100644
--- a/src/mongo/db/repl/repl_settings.h
+++ b/src/mongo/db/repl/repl_settings.h
@@ -28,11 +28,9 @@
 
 #pragma once
 
-#include <set>
 #include <string>
 
 #include "mongo/db/jsobj.h"
-#include "mongo/util/concurrency/mutex.h"
 
 namespace mongo {
 namespace repl {
@@ -56,15 +54,7 @@ public:
     /**
      * Getters
      */
-    bool isSlave() const;
-    bool isMaster() const;
-    bool isFastSyncEnabled() const;
-    bool isAutoResyncEnabled() const;
-    Seconds getSlaveDelaySecs() const;
-    int getPretouch() const;
     long long getOplogSizeBytes() const;
-    std::string getSource() const;
-    std::string getOnly() const;
     std::string getReplSetString() const;
 
     /**
@@ -82,38 +72,13 @@ public:
     /**
      * Setters
      */
-    void setSlave(bool slave);
-    void setMaster(bool master);
-    void setFastSyncEnabled(bool fastSyncEnabled);
-    void setAutoResyncEnabled(bool autoResyncEnabled);
-    void setSlaveDelaySecs(int slaveDelay);
-    void setPretouch(int pretouch);
     void setOplogSizeBytes(long long oplogSizeBytes);
-    void setSource(std::string source);
-    void setOnly(std::string only);
     void setReplSetString(std::string replSetString);
     void setPrefetchIndexMode(std::string prefetchIndexModeString);
 
 private:
-    /**
-     * true means we are master and doing replication.  If we are not writing to oplog, this won't
-     * be true.
-     */
-    bool _master = false;
-
-    // replication slave? (possibly with slave)
-    bool _slave = false;
-
-    bool _fastSyncEnabled = false;
-    bool _autoResyncEnabled = false;
-    Seconds _slaveDelaySecs = Seconds(0);
     long long _oplogSizeBytes = 0;  // --oplogSize
 
-    // for master/slave replication
-    std::string _source;  // --source
-    std::string _only;    // --only
-    int _pretouch = 0;    // --pretouch for replication application (experimental)
-
     std::string _replSetString;  // --replSet[/<seedlist>]
 
     // --indexPrefetch
diff --git a/src/mongo/db/repl/replication_coordinator.cpp b/src/mongo/db/repl/replication_coordinator.cpp
index 9c603c4db71..288cabf18a6 100644
--- a/src/mongo/db/repl/replication_coordinator.cpp
+++ b/src/mongo/db/repl/replication_coordinator.cpp
@@ -45,9 +45,6 @@ const auto getReplicationCoordinator =
 ReplicationCoordinator::ReplicationCoordinator() {}
 ReplicationCoordinator::~ReplicationCoordinator() {}
 
-// TODO(dannenberg) remove when master slave is removed
-const char* replAllDead = 0;
-
 ReplicationCoordinator* ReplicationCoordinator::get(ServiceContext* service) {
     return getReplicationCoordinator(service).get();
 }
diff --git a/src/mongo/db/repl/replication_coordinator.h b/src/mongo/db/repl/replication_coordinator.h
index bce17fa9ea6..96be0d7be59 100644
--- a/src/mongo/db/repl/replication_coordinator.h
+++ b/src/mongo/db/repl/replication_coordinator.h
@@ -80,16 +80,6 @@ class ReplSetRequestVotesResponse;
 class UpdatePositionArgs;
 
 /**
- * Global variable that contains a std::string telling why master/slave halted
- *
- * "dead" means something really bad happened like replication falling completely out of sync.
- * when non-null, we are dead and the string is informational
- *
- * TODO(dannenberg) remove when master slave goes
- */
-extern const char* replAllDead;
-
-/**
  * The ReplicationCoordinator is responsible for coordinating the interaction of replication
  * with the rest of the system.  The public methods on ReplicationCoordinator are the public
  * API that the replication subsystem presents to the rest of the codebase.
diff --git a/src/mongo/db/repl/replication_coordinator_external_state.h b/src/mongo/db/repl/replication_coordinator_external_state.h
index 17fe69b8a0d..38697e94c1c 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state.h
@@ -97,11 +97,6 @@ public:
     virtual void stopDataReplication(OperationContext* opCtx) = 0;
 
     /**
-     * Starts the Master/Slave threads and sets up logOp
-     */
-    virtual void startMasterSlave(OperationContext* opCtx) = 0;
-
-    /**
      * Performs any necessary external state specific shutdown tasks, such as cleaning up
      * the threads it started.
      */
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
index 474b15506af..00f2d968489 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
@@ -57,7 +57,6 @@
 #include "mongo/db/repl/drop_pending_collection_reaper.h"
 #include "mongo/db/repl/isself.h"
 #include "mongo/db/repl/last_vote.h"
-#include "mongo/db/repl/master_slave.h"
 #include "mongo/db/repl/member_state.h"
 #include "mongo/db/repl/noop_writer.h"
 #include "mongo/db/repl/oplog.h"
@@ -325,10 +324,6 @@ void ReplicationCoordinatorExternalStateImpl::startThreads(const ReplSettings& s
     _startedThreads = true;
 }
 
-void ReplicationCoordinatorExternalStateImpl::startMasterSlave(OperationContext* opCtx) {
-    repl::startMasterSlave(opCtx);
-}
-
 void ReplicationCoordinatorExternalStateImpl::shutdown(OperationContext* opCtx) {
     UniqueLock lk(_threadMutex);
     if (!_startedThreads) {
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_impl.h b/src/mongo/db/repl/replication_coordinator_external_state_impl.h
index 93e8149e3b3..3d124a24ef2 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.h
@@ -74,7 +74,6 @@ public:
 
     virtual bool isInitialSyncFlagSet(OperationContext* opCtx) override;
 
-    virtual void startMasterSlave(OperationContext* opCtx);
     virtual void shutdown(OperationContext* opCtx);
     virtual executor::TaskExecutor* getTaskExecutor() const override;
     virtual ThreadPool* getDbWorkThreadPool() const override;
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp b/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
index 29648d65bad..5f88d85e0ec 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
@@ -72,8 +72,6 @@ void ReplicationCoordinatorExternalStateMock::startSteadyStateReplication(Operat
 
 void ReplicationCoordinatorExternalStateMock::stopDataReplication(OperationContext*) {}
 
-void ReplicationCoordinatorExternalStateMock::startMasterSlave(OperationContext*) {}
-
 Status ReplicationCoordinatorExternalStateMock::runRepairOnLocalDB(OperationContext* opCtx) {
     return Status::OK();
 }
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_mock.h b/src/mongo/db/repl/replication_coordinator_external_state_mock.h
index 693a95ce4e2..2d7f5563bba 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_mock.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state_mock.h
@@ -62,7 +62,6 @@ public:
     virtual void stopDataReplication(OperationContext* opCtx) override;
     virtual bool isInitialSyncFlagSet(OperationContext* opCtx) override;
 
-    virtual void startMasterSlave(OperationContext*);
     virtual void shutdown(OperationContext* opCtx);
     virtual executor::TaskExecutor* getTaskExecutor() const override;
     virtual ThreadPool* getDbWorkThreadPool() const override;
diff --git a/src/mongo/db/repl/replication_coordinator_impl.cpp b/src/mongo/db/repl/replication_coordinator_impl.cpp
index f3393400981..bbf1aa7d020 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl.cpp
@@ -303,9 +303,6 @@ ReplicationCoordinator::Mode getReplicationModeFromSettings(const ReplSettings&
     if (settings.usingReplSets()) {
         return ReplicationCoordinator::modeReplSet;
     }
-    if (settings.isMaster() || settings.isSlave()) {
-        return ReplicationCoordinator::modeMasterSlave;
-    }
     return ReplicationCoordinator::modeNone;
 }
 
@@ -347,7 +344,7 @@ ReplicationCoordinatorImpl::ReplicationCoordinatorImpl(
       _rsConfigState(kConfigPreStart),
       _selfIndex(-1),
       _sleptLastElection(false),
-      _canAcceptNonLocalWrites(!(settings.usingReplSets() || settings.isSlave())),
+      _canAcceptNonLocalWrites(!settings.usingReplSets()),
       _canServeNonLocalReads(0U),
       _replicationProcess(replicationProcess),
       _storage(storage),
@@ -736,6 +733,7 @@ void ReplicationCoordinatorImpl::startup(OperationContext* opCtx) {
         _setConfigState_inlock(kConfigReplicationDisabled);
         return;
     }
+    invariant(_settings.usingReplSets());
 
     {
         OID rid = _externalState->ensureMe(opCtx);
@@ -747,13 +745,6 @@ void ReplicationCoordinatorImpl::startup(OperationContext* opCtx) {
         _topCoord->setMyRid(rid);
     }
 
-    if (!_settings.usingReplSets()) {
-        // Must be Master/Slave
-        invariant(_settings.isMaster() || _settings.isSlave());
-        _externalState->startMasterSlave(opCtx);
-        return;
-    }
-
     _replExecutor->startup();
 
     {
@@ -1752,29 +1743,13 @@ void ReplicationCoordinatorImpl::_handleTimePassing(
 }
 
 bool ReplicationCoordinatorImpl::isMasterForReportingPurposes() {
-    if (_settings.usingReplSets()) {
-        stdx::lock_guard<stdx::mutex> lock(_mutex);
-        if (getReplicationMode() == modeReplSet && _getMemberState_inlock().primary()) {
-            return true;
-        }
-        return false;
-    }
-
-    if (!_settings.isSlave())
-        return true;
-
-
-    // TODO(dannenberg) replAllDead is bad and should be removed when master slave is removed
-    if (replAllDead) {
-        return false;
-    }
-
-    if (_settings.isMaster()) {
-        // if running with --master --slave, allow.
+    if (!_settings.usingReplSets()) {
         return true;
     }
 
-    return false;
+    stdx::lock_guard<stdx::mutex> lock(_mutex);
+    invariant(getReplicationMode() == modeReplSet);
+    return _getMemberState_inlock().primary();
 }
 
 bool ReplicationCoordinatorImpl::canAcceptWritesForDatabase(OperationContext* opCtx,
@@ -1786,20 +1761,18 @@ bool ReplicationCoordinatorImpl::canAcceptWritesForDatabase(OperationContext* op
 
 bool ReplicationCoordinatorImpl::canAcceptWritesForDatabase_UNSAFE(OperationContext* opCtx,
                                                                    StringData dbName) {
-    // _canAcceptNonLocalWrites is always true for standalone nodes, always false for nodes
-    // started with --slave, and adjusted based on primary+drain state in replica sets.
+    // _canAcceptNonLocalWrites is always true for standalone nodes, and adjusted based on
+    // primary+drain state in replica sets.
     //
-    // That is, stand-alone nodes, non-slave nodes and drained replica set primaries can always
-    // accept writes.  Similarly, writes are always permitted to the "local" database.  Finally,
-    // in the event that a node is started with --slave and --master, we allow writes unless the
-    // master/slave system has set the replAllDead flag.
+    // Stand-alone nodes and drained replica set primaries can always accept writes.  Writes are
+    // always permitted to the "local" database.
     if (_canAcceptNonLocalWrites || alwaysAllowNonLocalWrites(*opCtx)) {
         return true;
     }
     if (dbName == kLocalDB) {
         return true;
     }
-    return !replAllDead && _settings.isMaster();
+    return false;
 }
 
 bool ReplicationCoordinatorImpl::canAcceptWritesFor(OperationContext* opCtx,
diff --git a/src/mongo/db/repl/replication_coordinator_mock.cpp b/src/mongo/db/repl/replication_coordinator_mock.cpp
index 25141375b23..bbc70047e36 100644
--- a/src/mongo/db/repl/replication_coordinator_mock.cpp
+++ b/src/mongo/db/repl/replication_coordinator_mock.cpp
@@ -78,16 +78,13 @@ const ReplSettings& ReplicationCoordinatorMock::getSettings() const {
 }
 
 bool ReplicationCoordinatorMock::isReplEnabled() const {
-    return _settings.usingReplSets() || _settings.isMaster() || _settings.isSlave();
+    return _settings.usingReplSets();
 }
 
 ReplicationCoordinator::Mode ReplicationCoordinatorMock::getReplicationMode() const {
     if (_settings.usingReplSets()) {
         return modeReplSet;
     }
-    if (_settings.isMaster() || _settings.isSlave()) {
-        return modeMasterSlave;
-    }
     return modeNone;
 }
 
@@ -141,7 +138,7 @@ bool ReplicationCoordinatorMock::canAcceptWritesForDatabase(OperationContext* op
     if (_alwaysAllowWrites) {
         return true;
     }
-    return dbName == "local" || _memberState.primary() || _settings.isMaster();
+    return dbName == "local" || _memberState.primary();
 }
 
 bool ReplicationCoordinatorMock::canAcceptWritesForDatabase_UNSAFE(OperationContext* opCtx,
@@ -494,10 +491,6 @@ void ReplicationCoordinatorMock::alwaysAllowWrites(bool allowWrites) {
     _alwaysAllowWrites = allowWrites;
 }
 
-void ReplicationCoordinatorMock::setMaster(bool isMaster) {
-    _settings.setMaster(isMaster);
-}
-
 Status ReplicationCoordinatorMock::abortCatchupIfNeeded() {
     return Status::OK();
 }
diff --git a/src/mongo/db/repl/replication_info.cpp b/src/mongo/db/repl/replication_info.cpp
index fc33d735f13..7ee9664690e 100644
--- a/src/mongo/db/repl/replication_info.cpp
+++ b/src/mongo/db/repl/replication_info.cpp
@@ -46,7 +46,6 @@
 #include "mongo/db/ops/write_ops.h"
 #include "mongo/db/query/internal_plans.h"
 #include "mongo/db/repl/is_master_response.h"
-#include "mongo/db/repl/master_slave.h"
 #include "mongo/db/repl/oplog.h"
 #include "mongo/db/repl/oplogreader.h"
 #include "mongo/db/repl/replication_coordinator.h"
@@ -88,15 +87,8 @@ void appendReplicationInfo(OperationContext* opCtx, BSONObjBuilder& result, int
         return;
     }
 
-    // TODO(dannenberg) replAllDead is bad and should be removed when master slave is removed
-    if (replAllDead) {
-        result.append("ismaster", 0);
-        string s = string("dead: ") + replAllDead;
-        result.append("info", s);
-    } else {
-        result.appendBool("ismaster",
-                          ReplicationCoordinator::get(opCtx)->isMasterForReportingPurposes());
-    }
+    result.appendBool("ismaster",
+                      ReplicationCoordinator::get(opCtx)->isMasterForReportingPurposes());
 
     if (level) {
         BSONObjBuilder sources(result.subarrayStart("sources"));
diff --git a/src/mongo/db/repl/resync.cpp b/src/mongo/db/repl/resync.cpp
deleted file mode 100644
index 4141485cb93..00000000000
--- a/src/mongo/db/repl/resync.cpp
+++ /dev/null
@@ -1,160 +0,0 @@
-/**
-*    Copyright (C) 2008 10gen Inc.
-*
-*    This program is free software: you can redistribute it and/or  modify
-*    it under the terms of the GNU Affero General Public License, version 3,
-*    as published by the Free Software Foundation.
-*
-*    This program is distributed in the hope that it will be useful,
-*    but WITHOUT ANY WARRANTY; without even the implied warranty of
-*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-*    GNU Affero General Public License for more details.
-*
-*    You should have received a copy of the GNU Affero General Public License
-*    along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*
-*    As a special exception, the copyright holders give permission to link the
-*    code of portions of this program with the OpenSSL library under certain
-*    conditions as described in each individual source file and distribute
-*    linked combinations including the program with the OpenSSL library. You
-*    must comply with the GNU Affero General Public License in all respects for
-*    all of the code used other than as permitted herein. If you modify file(s)
-*    with this exception, you may extend this exception to your version of the
-*    file(s), but you are not obligated to do so. If you do not wish to do so,
-*    delete this exception statement from your version. If you delete this
-*    exception statement from all source files in the program, then also delete
-*    it in the license file.
-*/
-
-#include "mongo/db/commands.h"
-#include "mongo/db/concurrency/d_concurrency.h"
-#include "mongo/db/operation_context.h"
-#include "mongo/db/repl/master_slave.h"  // replSettings
-#include "mongo/db/repl/replication_coordinator.h"
-
-namespace mongo {
-
-using std::string;
-using std::stringstream;
-
-namespace repl {
-
-namespace {
-
-constexpr StringData kResyncFieldName = "resync"_sd;
-constexpr StringData kWaitFieldName = "wait"_sd;
-
-}  // namespace
-
-// operator requested resynchronization of replication (on a slave or secondary). {resync: 1}
-class CmdResync : public ErrmsgCommandDeprecated {
-public:
-    AllowedOnSecondary secondaryAllowed(ServiceContext*) const override {
-        return AllowedOnSecondary::kAlways;
-    }
-    virtual bool adminOnly() const {
-        return true;
-    }
-    virtual bool supportsWriteConcern(const BSONObj& cmd) const override {
-        return false;
-    }
-    virtual void addRequiredPrivileges(const std::string& dbname,
-                                       const BSONObj& cmdObj,
-                                       std::vector<Privilege>* out) const {
-        ActionSet actions;
-        actions.addAction(ActionType::resync);
-        out->push_back(Privilege(ResourcePattern::forClusterResource(), actions));
-    }
-
-    std::string help() const override {
-        return "resync (from scratch) a stale slave or replica set secondary node.\n";
-    }
-
-    CmdResync() : ErrmsgCommandDeprecated(kResyncFieldName) {}
-    virtual bool errmsgRun(OperationContext* opCtx,
-                           const string& dbname,
-                           const BSONObj& cmdObj,
-                           string& errmsg,
-                           BSONObjBuilder& result) {
-        bool waitForResync = !cmdObj.hasField(kWaitFieldName) || cmdObj[kWaitFieldName].trueValue();
-
-        // Replica set resync.
-        ReplicationCoordinator* replCoord = ReplicationCoordinator::get(opCtx);
-        if (replCoord->getSettings().usingReplSets()) {
-            // Resync is disabled in production on replica sets until it stabilizes (SERVER-27081).
-            if (!Command::testCommandsEnabled) {
-                return CommandHelpers::appendCommandStatus(
-                    result,
-                    Status(ErrorCodes::OperationFailed,
-                           "Replica sets do not support the resync command"));
-            }
-
-            {
-                // Need global write lock to transition out of SECONDARY
-                Lock::GlobalWrite globalWriteLock(opCtx);
-
-                const MemberState memberState = replCoord->getMemberState();
-                if (memberState.startup()) {
-                    return CommandHelpers::appendCommandStatus(
-                        result, Status(ErrorCodes::NotYetInitialized, "no replication yet active"));
-                }
-                if (memberState.primary()) {
-                    return CommandHelpers::appendCommandStatus(
-                        result, Status(ErrorCodes::NotSecondary, "primaries cannot resync"));
-                }
-                auto status = replCoord->setFollowerMode(MemberState::RS_STARTUP2);
-                if (!status.isOK()) {
-                    return CommandHelpers::appendCommandStatus(
-                        result,
-                        status.withContext(
-                            "Failed to transition to STARTUP2 state to perform resync"));
-                }
-            }
-            uassertStatusOKWithLocation(replCoord->resyncData(opCtx, waitForResync), "resync", 0);
-            return true;
-        }
-
-        // Master/Slave resync.
-        Lock::GlobalWrite globalWriteLock(opCtx);
-        // below this comment pertains only to master/slave replication
-        if (cmdObj.getBoolField("force")) {
-            if (!waitForSyncToFinish(opCtx, errmsg))
-                return false;
-            replAllDead = "resync forced";
-        }
-        // TODO(dannenberg) replAllDead is bad and should be removed when masterslave is removed
-        if (!replAllDead) {
-            errmsg = "not dead, no need to resync";
-            return false;
-        }
-        if (!waitForSyncToFinish(opCtx, errmsg))
-            return false;
-
-        ReplSource::forceResyncDead(opCtx, "client");
-        result.append("info", "triggered resync for all sources");
-
-        return true;
-    }
-
-    bool waitForSyncToFinish(OperationContext* opCtx, string& errmsg) const {
-        // Wait for slave thread to finish syncing, so sources will be be
-        // reloaded with new saved state on next pass.
-        Timer t;
-        while (1) {
-            if (syncing.load() == 0 || t.millis() > 30000)
-                break;
-            {
-                Lock::TempRelease t(opCtx->lockState());
-                relinquishSyncingSome.store(1);
-                sleepmillis(1);
-            }
-        }
-        if (syncing.load()) {
-            errmsg = "timeout waiting for sync() to finish";
-            return false;
-        }
-        return true;
-    }
-} cmdResync;
-}  // namespace repl
-}  // namespace mongo
diff --git a/src/mongo/dbtests/repltests.cpp b/src/mongo/dbtests/repltests.cpp
index 8ccb88af950..4eff300faf9 100644
--- a/src/mongo/dbtests/repltests.cpp
+++ b/src/mongo/dbtests/repltests.cpp
@@ -45,7 +45,6 @@
 #include "mongo/db/json.h"
 #include "mongo/db/op_observer_impl.h"
 #include "mongo/db/ops/update.h"
-#include "mongo/db/repl/master_slave.h"
 #include "mongo/db/repl/oplog.h"
 #include "mongo/db/repl/repl_client_info.h"
 #include "mongo/db/repl/replication_coordinator.h"
@@ -121,12 +120,13 @@ public:
         ASSERT_OK(sc->getTransportLayer()->start());
 
         ReplSettings replSettings;
-        replSettings.setOplogSizeBytes(10 * 1024 * 1024);
-        replSettings.setMaster(true);
+        replSettings.setReplSetString("rs0/host1");
         ReplicationCoordinator::set(
             getGlobalServiceContext(),
             std::unique_ptr<repl::ReplicationCoordinator>(
                 new repl::ReplicationCoordinatorMock(_opCtx.getServiceContext(), replSettings)));
+        ASSERT_OK(ReplicationCoordinator::get(getGlobalServiceContext())
+                      ->setFollowerMode(MemberState::RS_PRIMARY));
 
         // Since the Client object persists across tests, even though the global
         // ReplicationCoordinator does not, we need to clear the last op associated with the client
@@ -177,7 +177,7 @@ protected:
         return "unittests.repltests";
     }
     static const char* cllNS() {
-        return "local.oplog.$main";
+        return "local.oplog.rs";
     }
     BSONObj one(const BSONObj& query = BSONObj()) const {
         return _client.findOne(ns(), query);
@@ -235,16 +235,13 @@ protected:
         }
         {
             OldClientContext ctx(&_opCtx, ns());
-            BSONObjBuilder b;
-            b.append("host", "localhost");
-            b.appendTimestamp("syncedTo", 0);
-            ReplSource a(&_opCtx, b.obj());
             for (vector<BSONObj>::iterator i = ops.begin(); i != ops.end(); ++i) {
                 if (0) {
                     mongo::unittest::log() << "op: " << *i << endl;
                 }
                 repl::UnreplicatedWritesBlock uwb(&_opCtx);
-                a.applyOperation(&_opCtx, ctx.db(), *i);
+                uassertStatusOK(applyOperation_inlock(
+                    &_opCtx, ctx.db(), *i, false, OplogApplication::Mode::kSecondary));
             }
         }
     }
@@ -329,9 +326,9 @@ public:
         if (mongo::storageGlobalParams.engine == "mobile") {
             return;
         }
-        ASSERT_EQUALS(2, opCount());
+        ASSERT_EQUALS(1, opCount());
         _client.insert(ns(), fromjson("{\"a\":\"b\"}"));
-        ASSERT_EQUALS(3, opCount());
+        ASSERT_EQUALS(2, opCount());
     }
 };
 
@@ -1346,50 +1343,6 @@ public:
     }
 };
 
-class DatabaseIgnorerBasic {
-public:
-    void run() {
-        // Replication is not supported by mobile SE.
-        if (mongo::storageGlobalParams.engine == "mobile") {
-            return;
-        }
-        DatabaseIgnorer d;
-        ASSERT(!d.ignoreAt("a", Timestamp(4, 0)));
-        d.doIgnoreUntilAfter("a", Timestamp(5, 0));
-        ASSERT(d.ignoreAt("a", Timestamp(4, 0)));
-        ASSERT(!d.ignoreAt("b", Timestamp(4, 0)));
-        ASSERT(d.ignoreAt("a", Timestamp(4, 10)));
-        ASSERT(d.ignoreAt("a", Timestamp(5, 0)));
-        ASSERT(!d.ignoreAt("a", Timestamp(5, 1)));
-        // Ignore state is expired.
-        ASSERT(!d.ignoreAt("a", Timestamp(4, 0)));
-    }
-};
-
-class DatabaseIgnorerUpdate {
-public:
-    void run() {
-        // Replication is not supported by mobile SE.
-        if (mongo::storageGlobalParams.engine == "mobile") {
-            return;
-        }
-        DatabaseIgnorer d;
-        d.doIgnoreUntilAfter("a", Timestamp(5, 0));
-        d.doIgnoreUntilAfter("a", Timestamp(6, 0));
-        ASSERT(d.ignoreAt("a", Timestamp(5, 5)));
-        ASSERT(d.ignoreAt("a", Timestamp(6, 0)));
-        ASSERT(!d.ignoreAt("a", Timestamp(6, 1)));
-
-        d.doIgnoreUntilAfter("a", Timestamp(5, 0));
-        d.doIgnoreUntilAfter("a", Timestamp(6, 0));
-        d.doIgnoreUntilAfter("a", Timestamp(6, 0));
-        d.doIgnoreUntilAfter("a", Timestamp(5, 0));
-        ASSERT(d.ignoreAt("a", Timestamp(5, 5)));
-        ASSERT(d.ignoreAt("a", Timestamp(6, 0)));
-        ASSERT(!d.ignoreAt("a", Timestamp(6, 1)));
-    }
-};
-
 class SyncTest : public SyncTail {
 public:
     bool returnEmpty;
@@ -1511,8 +1464,6 @@ public:
         add<Idempotence::ReplaySetPreexistingNoOpPull>();
         add<Idempotence::ReplayArrayFieldNotAppended>();
         add<DeleteOpIsIdBased>();
-        add<DatabaseIgnorerBasic>();
-        add<DatabaseIgnorerUpdate>();
         add<FetchAndInsertMissingDocument>();
     }
 };
diff --git a/src/mongo/s/sharding_mongod_test_fixture.cpp b/src/mongo/s/sharding_mongod_test_fixture.cpp
index cbf5099a2df..f9a54847fd2 100644
--- a/src/mongo/s/sharding_mongod_test_fixture.cpp
+++ b/src/mongo/s/sharding_mongod_test_fixture.cpp
@@ -105,7 +105,6 @@ void ShardingMongodTestFixture::setUp() {
 
     repl::ReplSettings replSettings;
     replSettings.setReplSetString(ConnectionString::forReplicaSet(_setName, _servers).toString());
-    replSettings.setMaster(true);
     auto replCoordPtr = makeReplicationCoordinator(replSettings);
     _replCoord = replCoordPtr.get();
 
@@ -156,7 +155,10 @@ void ShardingMongodTestFixture::setUp() {
 
 std::unique_ptr<ReplicationCoordinatorMock> ShardingMongodTestFixture::makeReplicationCoordinator(
     ReplSettings replSettings) {
-    return stdx::make_unique<repl::ReplicationCoordinatorMock>(getServiceContext(), replSettings);
+    auto coordinator =
+        stdx::make_unique<repl::ReplicationCoordinatorMock>(getServiceContext(), replSettings);
+    ASSERT_OK(coordinator->setFollowerMode(repl::MemberState::RS_PRIMARY));
+    return coordinator;
 }
 
 std::unique_ptr<executor::TaskExecutorPool> ShardingMongodTestFixture::makeTaskExecutorPool() {