SERVER-32691 Add write_concern_majority_passthrough.yml test suite.

Also adds support for using replica set connection strings in resmoke.py
without making all nodes electable.

(cherry picked from commit 264d971842cffdf8b4f80def1d90241f132345b7)

28 files changed, 574 insertions, 153 deletions

diff --git a/buildscripts/resmokeconfig/suites/write_concern_majority_passthrough.yml b/buildscripts/resmokeconfig/suites/write_concern_majority_passthrough.yml
new file mode 100644
index 00000000000..614e0834e67
--- /dev/null
+++ b/buildscripts/resmokeconfig/suites/write_concern_majority_passthrough.yml
@@ -0,0 +1,77 @@
+test_kind: js_test
+
+selector:
+  js_test:
+    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
+    # The connection_string_validation.js test does not expect the mongo shell to be using a replica
+    # set connection string.
+    - jstests/core/connection_string_validation.js
+    # These tests attempt to read from the "system.profile" collection, which may be missing entries
+    # if a write was performed on the primary of the replica set instead.
+    - jstests/core/*profile*.js
+    # The shellkillop.js test spawns a parallel shell without using startParallelShell() and
+    # therefore doesn't inherit the w="majority" write concern when performing its writes.
+    - jstests/core/shellkillop.js
+    exclude_with_any_tags:
+    ##
+    # The next three tags correspond to the special errors thrown by the
+    # set_read_and_write_concerns.js override when it refuses to replace the readConcern or
+    # writeConcern of a particular command. Above each tag are the message(s) that cause the tag to
+    # be warranted.
+    ##
+    # "Cowardly refusing to override read concern of command: ..."
+    - assumes_read_concern_unchanged
+    # "Cowardly refusing to override write concern of command: ..."
+    - assumes_write_concern_unchanged
+    # "Cowardly refusing to run test with overridden write concern when it uses a command that can
+    #  only perform w=1 writes: ..."
+    - requires_eval_command
+    ##
+    # The next tag corresponds to the special error thrown by the set_read_preference_secondary.js
+    # override when it refuses to replace the readPreference of a particular command. Above each tag
+    # are the message(s) that cause the tag to be warranted.
+    ##
+    # "Cowardly refusing to override read preference of command: ..."
+    # "Cowardly refusing to run test with overridden read preference when it reads from a
+    #  non-replicated collection: ..."
+    - assumes_read_preference_unchanged
+
+executor:
+  js_test:
+    config:
+      shell_options:
+        global_vars:
+          TestData:
+            defaultReadConcernLevel: local
+        eval: >-
+          testingReplication = true;
+          load('jstests/libs/override_methods/set_read_and_write_concerns.js');
+          load('jstests/libs/override_methods/set_read_preference_secondary.js');
+        readMode: commands
+    hooks:
+    # The CheckReplDBHash hook waits until all operations have replicated to and have been applied
+    # on the secondaries, so we run the ValidateCollections hook after it to ensure we're
+    # validating the entire contents of the collection.
+    - class: CheckReplOplogs
+    - class: CheckReplDBHash
+    - class: ValidateCollections
+    - class: CleanEveryN
+      n: 20
+    fixture:
+      class: ReplicaSetFixture
+      mongod_options:
+        set_parameters:
+          enableTestCommands: 1
+          numInitialSyncAttempts: 1
+      # This suite requires w="majority" writes to be applied on all secondaries. By using a 2-node
+      # replica set and having secondaries vote, the majority of the replica set is all nodes.
+      num_nodes: 2
+      voting_secondaries: true
+      use_replica_set_connection_string: true
diff --git a/buildscripts/resmokelib/core/programs.py b/buildscripts/resmokelib/core/programs.py
index e4cadc8e006..d94cd438ee0 100644
--- a/buildscripts/resmokelib/core/programs.py
+++ b/buildscripts/resmokelib/core/programs.py
@@ -115,8 +115,8 @@ def mongos_program(logger, executable=None, process_kwargs=None, **kwargs):
     return _process.Process(logger, args, **process_kwargs)
 
 
-def mongo_shell_program(logger, executable=None, filename=None, process_kwargs=None,
-                        isMainTest=True, **kwargs):
+def mongo_shell_program(logger, executable=None, connection_string=None, filename=None,
+                        process_kwargs=None, isMainTest=True, **kwargs):
     """
     Returns a Process instance that starts a mongo shell with arguments
     constructed from 'kwargs'.
@@ -184,9 +184,22 @@ def mongo_shell_program(logger, executable=None, filename=None, process_kwargs=N
     if config.SHELL_WRITE_MODE is not None:
         kwargs["writeMode"] = config.SHELL_WRITE_MODE
 
+    if connection_string is not None:
+        # The --host and --port options are ignored by the mongo shell when an explicit connection
+        # string is specified. We remove these options to avoid any ambiguity with what server the
+        # logged mongo shell invocation will connect to.
+        if "port" in kwargs:
+            kwargs.pop("port")
+
+        if "host" in kwargs:
+            kwargs.pop("host")
+
     # Apply the rest of the command line arguments.
     _apply_kwargs(args, kwargs)
 
+    if connection_string is not None:
+        args.append(connection_string)
+
     # Have the mongos shell run the specified file.
     args.append(filename)
 
diff --git a/buildscripts/resmokelib/testing/fixtures/interface.py b/buildscripts/resmokelib/testing/fixtures/interface.py
index b4b0066a5aa..83418502ead 100644
--- a/buildscripts/resmokelib/testing/fixtures/interface.py
+++ b/buildscripts/resmokelib/testing/fixtures/interface.py
@@ -79,13 +79,22 @@ class Fixture(object):
         """
         return True
 
-    def get_connection_string(self):
+    def get_internal_connection_string(self):
         """
         Returns the connection string for this fixture. This is NOT a
         driver connection string, but a connection string of the format
         expected by the mongo::ConnectionString class.
         """
-        raise NotImplementedError("get_connection_string must be implemented by Fixture subclasses")
+        raise NotImplementedError(
+            "get_internal_connection_string must be implemented by Fixture subclasses")
+
+    def get_driver_connection_url(self):
+        """
+        Return the mongodb connection string as defined here:
+        https://docs.mongodb.com/manual/reference/connection-string/
+        """
+        raise NotImplementedError(
+            "get_driver_connection_url must be implemented by Fixture subclasses")
 
     def __str__(self):
         return "%s (Job #%d)" % (self.__class__.__name__, self.job_num)
diff --git a/buildscripts/resmokelib/testing/fixtures/masterslave.py b/buildscripts/resmokelib/testing/fixtures/masterslave.py
index 469c7ac0816..fb444cfe097 100644
--- a/buildscripts/resmokelib/testing/fixtures/masterslave.py
+++ b/buildscripts/resmokelib/testing/fixtures/masterslave.py
@@ -5,7 +5,6 @@ Master/slave fixture for executing JSTests against.
 from __future__ import absolute_import
 
 import os.path
-import socket
 
 import pymongo
 
@@ -160,6 +159,12 @@ class MasterSlaveFixture(interface.ReplFixture):
         mongod_options = self.mongod_options.copy()
         mongod_options.update(self.slave_options)
         mongod_options["slave"] = ""
-        mongod_options["source"] = "%s:%d" % (socket.gethostname(), self.port)
+        mongod_options["source"] = self.master.get_internal_connection_string()
         mongod_options["dbpath"] = os.path.join(self._dbpath_prefix, "slave")
         return self._new_mongod(mongod_logger, mongod_options)
+
+    def get_internal_connection_string(self):
+        return self.master.get_internal_connection_string()
+
+    def get_driver_connection_url(self):
+        return self.master.get_driver_connection_url()
diff --git a/buildscripts/resmokelib/testing/fixtures/replicaset.py b/buildscripts/resmokelib/testing/fixtures/replicaset.py
index fb578bafe6f..0ec3de30280 100644
--- a/buildscripts/resmokelib/testing/fixtures/replicaset.py
+++ b/buildscripts/resmokelib/testing/fixtures/replicaset.py
@@ -37,7 +37,8 @@ class ReplicaSetFixture(interface.ReplFixture):
                  write_concern_majority_journal_default=None,
                  auth_options=None,
                  replset_config_options=None,
-                 voting_secondaries=False):
+                 voting_secondaries=False,
+                 use_replica_set_connection_string=False):
 
         interface.ReplFixture.__init__(self, logger, job_num)
 
@@ -50,6 +51,7 @@ class ReplicaSetFixture(interface.ReplFixture):
         self.auth_options = auth_options
         self.replset_config_options = utils.default_if_none(replset_config_options, {})
         self.voting_secondaries = voting_secondaries
+        self.use_replica_set_connection_string = use_replica_set_connection_string
 
         # The dbpath in mongod_options is used as the dbpath prefix for replica set members and
         # takes precedence over other settings. The ShardedClusterFixture uses this parameter to
@@ -97,7 +99,7 @@ class ReplicaSetFixture(interface.ReplFixture):
         # Initiate the replica set.
         members = []
         for (i, node) in enumerate(self.nodes):
-            member_info = {"_id": i, "host": node.get_connection_string()}
+            member_info = {"_id": i, "host": node.get_internal_connection_string()}
             if i > 0:
                 member_info["priority"] = 0
                 if i >= 7 or not self.voting_secondaries:
@@ -107,7 +109,7 @@ class ReplicaSetFixture(interface.ReplFixture):
             members.append(member_info)
         if self.initial_sync_node:
             members.append({"_id": self.initial_sync_node_idx,
-                            "host": self.initial_sync_node.get_connection_string(),
+                            "host": self.initial_sync_node.get_internal_connection_string(),
                             "priority": 0,
                             "hidden": 1,
                             "votes": 0})
@@ -291,11 +293,27 @@ class ReplicaSetFixture(interface.ReplFixture):
 
         return logging.loggers.new_logger(logger_name, parent=self.logger)
 
-    def get_connection_string(self):
+    def get_internal_connection_string(self):
         if self.replset_name is None:
-            raise ValueError("Must call setup() before calling get_connection_string()")
+            raise ValueError("Must call setup() before calling get_internal_connection_string()")
 
-        conn_strs = [node.get_connection_string() for node in self.nodes]
+        conn_strs = [node.get_internal_connection_string() for node in self.nodes]
         if self.initial_sync_node:
-            conn_strs.append(self.initial_sync_node.get_connection_string())
+            conn_strs.append(self.initial_sync_node.get_internal_connection_string())
         return self.replset_name + "/" + ",".join(conn_strs)
+
+    def get_driver_connection_url(self):
+        if self.replset_name is None:
+            raise ValueError("Must call setup() before calling get_driver_connection_url()")
+
+        if self.use_replica_set_connection_string:
+            # We use a replica set connection string when all nodes are electable because we
+            # anticipate the client will want to gracefully handle any failovers.
+            conn_strs = [node.get_internal_connection_string() for node in self.nodes]
+            if self.initial_sync_node:
+                conn_strs.append(self.initial_sync_node.get_internal_connection_string())
+            return "mongodb://" + ",".join(conn_strs) + "/?replicaSet=" + self.replset_name
+        else:
+            # We return a direct connection to the expected pimary when only the first node is
+            # electable because we want the client to error out if a stepdown occurs.
+            return self.nodes[0].get_driver_connection_url()
diff --git a/buildscripts/resmokelib/testing/fixtures/shardedcluster.py b/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
index ac7e597f24b..2e2db535d6d 100644
--- a/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
+++ b/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
@@ -170,11 +170,14 @@ class ShardedClusterFixture(interface.Fixture):
                 all(shard.is_running() for shard in self.shards) and
                 self.mongos is not None and self.mongos.is_running())
 
-    def get_connection_string(self):
+    def get_internal_connection_string(self):
         if self.mongos is None:
-            raise ValueError("Must call setup() before calling get_connection_string()")
+            raise ValueError("Must call setup() before calling get_internal_connection_string()")
 
-        return "%s:%d" % (socket.gethostname(), self.mongos.port)
+        return self.mongos.get_internal_connection_string()
+
+    def get_driver_connection_url(self):
+        return "mongodb://" + self.get_internal_connection_string()
 
     def _new_configsvr(self):
         """
@@ -229,16 +232,11 @@ class ShardedClusterFixture(interface.Fixture):
         mongos_logger = logging.loggers.new_logger(logger_name, parent=self.logger)
 
         mongos_options = copy.deepcopy(self.mongos_options)
-        configdb_hostname = socket.gethostname()
 
         if self.separate_configsvr:
-            configdb_replset = ShardedClusterFixture._CONFIGSVR_REPLSET_NAME
-            configdb_port = self.configsvr.port
-            mongos_options["configdb"] = "%s/%s:%d" % (configdb_replset,
-                                                       configdb_hostname,
-                                                       configdb_port)
+            mongos_options["configdb"] = self.configsvr.get_internal_connection_string()
         else:
-            mongos_options["configdb"] = "%s:%d" % (configdb_hostname, self.shards[0].port)
+            mongos_options["configdb"] = "localhost:%d" % (self.shards[0].port)
 
         return _MongoSFixture(mongos_logger,
                               self.job_num,
@@ -254,9 +252,9 @@ class ShardedClusterFixture(interface.Fixture):
         for more details.
         """
 
-        hostname = socket.gethostname()
-        self.logger.info("Adding %s:%d as a shard..." % (hostname, shard.port))
-        client.admin.command({"addShard": "%s:%d" % (hostname, shard.port)})
+        connection_string = shard.get_internal_connection_string()
+        self.logger.info("Adding %s as a shard...", connection_string)
+        client.admin.command({"addShard": connection_string})
 
 
 class _MongoSFixture(interface.Fixture):
@@ -356,3 +354,12 @@ class _MongoSFixture(interface.Fixture):
 
     def is_running(self):
         return self.mongos is not None and self.mongos.poll() is None
+
+    def get_internal_connection_string(self):
+        if self.mongos is None:
+            raise ValueError("Must call setup() before calling get_internal_connection_string()")
+
+        return "localhost:%d" % self.port
+
+    def get_driver_connection_url(self):
+        return "mongodb://" + self.get_internal_connection_string()
diff --git a/buildscripts/resmokelib/testing/fixtures/standalone.py b/buildscripts/resmokelib/testing/fixtures/standalone.py
index ba62b3d2b8c..bc69775c285 100644
--- a/buildscripts/resmokelib/testing/fixtures/standalone.py
+++ b/buildscripts/resmokelib/testing/fixtures/standalone.py
@@ -7,7 +7,6 @@ from __future__ import absolute_import
 import os
 import os.path
 import shutil
-import socket
 import time
 
 import pymongo
@@ -146,8 +145,11 @@ class MongoDFixture(interface.Fixture):
     def is_running(self):
         return self.mongod is not None and self.mongod.poll() is None
 
-    def get_connection_string(self):
+    def get_internal_connection_string(self):
         if self.mongod is None:
-            raise ValueError("Must call setup() before calling get_connection_string()")
+            raise ValueError("Must call setup() before calling get_internal_connection_string()")
 
-        return "%s:%d" % (socket.gethostname(), self.port)
+        return "localhost:%d" % self.port
+
+    def get_driver_connection_url(self):
+        return "mongodb://" + self.get_internal_connection_string()
diff --git a/buildscripts/resmokelib/testing/testcases.py b/buildscripts/resmokelib/testing/testcases.py
index 1428cb5e763..21d35215a29 100644
--- a/buildscripts/resmokelib/testing/testcases.py
+++ b/buildscripts/resmokelib/testing/testcases.py
@@ -187,7 +187,7 @@ class CPPIntegrationTestCase(TestCase):
     def configure(self, fixture, *args, **kwargs):
         TestCase.configure(self, fixture, *args, **kwargs)
 
-        self.program_options["connectionString"] = self.fixture.get_connection_string()
+        self.program_options["connectionString"] = self.fixture.get_internal_connection_string()
 
     def run_test(self):
         try:
@@ -421,11 +421,13 @@ class JSTestCase(TestCase):
         is_main_test = True
         if thread_id > 0:
             is_main_test = False
-        return core.programs.mongo_shell_program(logger,
-                                                 executable=self.shell_executable,
-                                                 filename=self.js_filename,
-                                                 isMainTest=is_main_test,
-                                                 **self.shell_options)
+        return core.programs.mongo_shell_program(
+            logger,
+            executable=self.shell_executable,
+            filename=self.js_filename,
+            connection_string=self.fixture.get_driver_connection_url(),
+            isMainTest=is_main_test,
+            **self.shell_options)
 
     def _run_test_in_thread(self, thread_id):
         # Make a logger for each thread.
diff --git a/jstests/core/collation_plan_cache.js b/jstests/core/collation_plan_cache.js
index 0eec77388e4..790bbbadaa6 100644
--- a/jstests/core/collation_plan_cache.js
+++ b/jstests/core/collation_plan_cache.js
@@ -1,4 +1,11 @@
 // Integration testing for the plan cache and index filter commands with collation.
+//
+// @tags: [
+//   # This test attempts to perform queries and introspect the server's plan cache entries. The
+//   # former operation may be routed to a secondary in the replica set, whereas the latter must be
+//   # routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 (function() {
     'use strict';
 
@@ -237,4 +244,4 @@
     assert.eq(0,
               coll.runCommand('planCacheListFilters').filters.length,
               'unexpected number of plan cache filters');
-})();
\ No newline at end of file
+})();
diff --git a/jstests/core/count10.js b/jstests/core/count10.js
index 2a1853c399a..453775c97f5 100644
--- a/jstests/core/count10.js
+++ b/jstests/core/count10.js
@@ -1,4 +1,11 @@
 // Test that interrupting a count returns an error code.
+//
+// @tags: [
+//   # This test attempts to perform a count command and find it using the currentOp command. The
+//   # former operation may be routed to a secondary in the replica set, whereas the latter must be
+//   # routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 t = db.count10;
 t.drop();
diff --git a/jstests/core/count_plan_summary.js b/jstests/core/count_plan_summary.js
index 48891d21e8e..365f289c457 100644
--- a/jstests/core/count_plan_summary.js
+++ b/jstests/core/count_plan_summary.js
@@ -1,5 +1,11 @@
-// Test that the plan summary string appears in db.currentOp() for
-// count operations. SERVER-14064.
+// Test that the plan summary string appears in db.currentOp() for count operations. SERVER-14064.
+//
+// @tags: [
+//   # This test attempts to perform a find command and find it using the currentOp command. The
+//   # former operation may be routed to a secondary in the replica set, whereas the latter must be
+//   # routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.jstests_count_plan_summary;
 t.drop();
diff --git a/jstests/core/geo_s2cursorlimitskip.js b/jstests/core/geo_s2cursorlimitskip.js
index 427fbf8fe29..dc645dc68af 100644
--- a/jstests/core/geo_s2cursorlimitskip.js
+++ b/jstests/core/geo_s2cursorlimitskip.js
@@ -1,4 +1,11 @@
 // Test various cursor behaviors
+//
+// @tags: [
+//   # This test attempts to enable profiling on a server and then get profiling data by reading
+//   # from the "system.profile" collection. The former operation must be routed to the primary in
+//   # a replica set, whereas the latter may be routed to a secondary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var testDB = db.getSiblingDB("geo_s2cursorlimitskip");
 var t = testDB.geo_s2getmmm;
diff --git a/jstests/core/getlog2.js b/jstests/core/getlog2.js
index 597a85e20ee..e5287ea8c1b 100644
--- a/jstests/core/getlog2.js
+++ b/jstests/core/getlog2.js
@@ -1,4 +1,11 @@
 // tests getlog as well as slow querying logging
+//
+// @tags: [
+//   # This test attempts to perform a find command and see that it ran using the getLog command.
+//   # The former operation may be routed to a secondary in the replica set, whereas the latter must
+//   # be routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 glcol = db.getLogTest2;
 glcol.drop();
diff --git a/jstests/core/index_filter_commands.js b/jstests/core/index_filter_commands.js
index 8684be3b2b9..58f78d0514e 100644
--- a/jstests/core/index_filter_commands.js
+++ b/jstests/core/index_filter_commands.js
@@ -6,20 +6,24 @@
  *   Displays index filters for all query shapes in a collection.
  *
  * - planCacheClearFilters
- *   Clears index filter for a single query shape or,
- *   if the query shape is omitted, all filters for the collection.
+ *   Clears index filter for a single query shape or, if the query shape is omitted, all filters for
+ *   the collection.
  *
  * - planCacheSetFilter
  *   Sets index filter for a query shape. Overrides existing filter.
  *
- * Not a lot of data access in this test suite. Hint commands
- * manage a non-persistent mapping in the server of
- * query shape to list of index specs.
+ * Not a lot of data access in this test suite. Hint commands manage a non-persistent mapping in the
+ * server of query shape to list of index specs.
  *
- * Only time we might need to execute a query is to check the plan
- * cache state. We would do this with the planCacheListPlans command
- * on the same query shape with the index filters.
+ * Only time we might need to execute a query is to check the plan cache state. We would do this
+ * with the planCacheListPlans command on the same query shape with the index filters.
  *
+ * @tags: [
+ *   # This test attempts to perform queries with plan cache filters set up. The former operation
+ *   # may be routed to a secondary in the replica set, whereas the latter must be routed to the
+ *   # primary.
+ *   assumes_read_preference_unchanged,
+ * ]
  */
 
 load("jstests/libs/analyze_plan.js");
diff --git a/jstests/core/index_stats.js b/jstests/core/index_stats.js
index 60b37fd571e..ee4d13d4d0a 100644
--- a/jstests/core/index_stats.js
+++ b/jstests/core/index_stats.js
@@ -1,3 +1,10 @@
+// @tags: [
+//   # This test attempts to perform write operations and get index usage statistics using the
+//   # $indexStats stage. The former operation must be routed to the primary in a replica set,
+//   # whereas the latter may be routed to a secondary.
+//   assumes_read_preference_unchanged,
+// ]
+
 (function() {
     "use strict";
 
diff --git a/jstests/core/max_time_ms.js b/jstests/core/max_time_ms.js
index 0442ffcba68..0cc7c684605 100644
--- a/jstests/core/max_time_ms.js
+++ b/jstests/core/max_time_ms.js
@@ -1,4 +1,11 @@
 // Tests query/command option $maxTimeMS.
+//
+// @tags: [
+//   # This test attempts to perform read operations after having enabled the maxTimeAlwaysTimeOut
+//   # failpoint. The former operations may be routed to a secondary in the replica set, whereas the
+//   # latter must be routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.max_time_ms;
 var exceededTimeLimit = 50;  // ErrorCodes::ExceededTimeLimit
diff --git a/jstests/core/mr_optim.js b/jstests/core/mr_optim.js
index 7437753ca67..1c525ae3de3 100644
--- a/jstests/core/mr_optim.js
+++ b/jstests/core/mr_optim.js
@@ -3,8 +3,17 @@
 t = db.mr_optim;
 t.drop();
 
+// We drop the output collection to ensure the test can be run multiple times successfully. We
+// explicitly avoid using the DBCollection#drop() shell helper to avoid implicitly sharding the
+// collection during the sharded_collections_jscore_passthrough.yml test suite when reading the
+// results from the output collection in the reformat() function.
+var res = db.runCommand({drop: "mr_optim_out"});
+if (res.ok !== 1) {
+    assert.commandFailedWithCode(res, ErrorCodes.NamespaceNotFound);
+}
+
 for (var i = 0; i < 1000; ++i) {
-    t.save({a: Math.random(1000), b: Math.random(10000)});
+    assert.writeOK(t.save({a: Math.random(1000), b: Math.random(10000)}));
 }
 
 function m() {
@@ -21,7 +30,7 @@ function reformat(r) {
     if (r.results)
         cursor = r.results;
     else
-        cursor = r.find();
+        cursor = r.find().sort({_id: 1});
     cursor.forEach(function(z) {
         x[z._id] = z.value;
     });
@@ -43,4 +52,4 @@ res.drop();
 
 assert.eq(x, x2, "object from inline and collection are not equal");
 
-t.drop();
\ No newline at end of file
+t.drop();
diff --git a/jstests/core/notablescan.js b/jstests/core/notablescan.js
index 80306c08cf2..bb4c170a603 100644
--- a/jstests/core/notablescan.js
+++ b/jstests/core/notablescan.js
@@ -1,4 +1,11 @@
 // check notablescan mode
+//
+// @tags: [
+//   # This test attempts to perform read operations after having enabled the notablescan server
+//   # parameter. The former operations may be routed to a secondary in the replica set, whereas the
+//   # latter must be routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 t = db.test_notablescan;
 t.drop();
diff --git a/jstests/core/operation_latency_histogram.js b/jstests/core/operation_latency_histogram.js
index 1e3f1a59b95..947a8be6520 100644
--- a/jstests/core/operation_latency_histogram.js
+++ b/jstests/core/operation_latency_histogram.js
@@ -1,4 +1,10 @@
 // Checks that histogram counters for collections are updated as we expect.
+//
+// This test attempts to perform write operations and get latency statistics using the $collStats
+// stage. The former operation must be routed to the primary in a replica set, whereas the latter
+// may be routed to a secondary.
+//
+// @tags: [assumes_read_preference_unchanged]
 
 (function() {
     "use strict";
diff --git a/jstests/core/plan_cache_clear.js b/jstests/core/plan_cache_clear.js
index 8f9cf0ea302..778239616b5 100644
--- a/jstests/core/plan_cache_clear.js
+++ b/jstests/core/plan_cache_clear.js
@@ -1,5 +1,12 @@
 // Test clearing of the plan cache, either manually through the planCacheClear command,
 // or due to system events such as an index build.
+//
+// @tags: [
+//   # This test attempts to perform queries and introspect/manipulate the server's plan cache
+//   # entries. The former operation may be routed to a secondary in the replica set, whereas the
+//   # latter must be routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.jstests_plan_cache_clear;
 t.drop();
diff --git a/jstests/core/plan_cache_list_plans.js b/jstests/core/plan_cache_list_plans.js
index 7ca599483ff..3359980ab07 100644
--- a/jstests/core/plan_cache_list_plans.js
+++ b/jstests/core/plan_cache_list_plans.js
@@ -1,4 +1,11 @@
 // Test the planCacheListPlans command.
+//
+// @tags: [
+//   # This test attempts to perform queries and introspect the server's plan cache entries. The
+//   # former operation may be routed to a secondary in the replica set, whereas the latter must be
+//   # routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.jstests_plan_cache_list_plans;
 t.drop();
diff --git a/jstests/core/plan_cache_list_shapes.js b/jstests/core/plan_cache_list_shapes.js
index 1c9ecdf9e1b..61c3111cd8a 100644
--- a/jstests/core/plan_cache_list_shapes.js
+++ b/jstests/core/plan_cache_list_shapes.js
@@ -1,5 +1,12 @@
 // Test the planCacheListQueryShapes command, which returns a list of query shapes
 // for the queries currently cached in the collection.
+//
+// @tags: [
+//   # This test attempts to perform queries with plan cache filters set up. The former operation
+//   # may be routed to a secondary in the replica set, whereas the latter must be routed to the
+//   # primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.jstests_plan_cache_list_shapes;
 t.drop();
diff --git a/jstests/core/plan_cache_shell_helpers.js b/jstests/core/plan_cache_shell_helpers.js
index dc990b19dcc..6c4ff185014 100644
--- a/jstests/core/plan_cache_shell_helpers.js
+++ b/jstests/core/plan_cache_shell_helpers.js
@@ -1,4 +1,11 @@
 // Test the shell helpers which wrap the plan cache commands.
+//
+// @tags: [
+//   # This test attempts to perform queries and introspect the server's plan cache entries. The
+//   # former operation may be routed to a secondary in the replica set, whereas the latter must be
+//   # routed to the primary.
+//   assumes_read_preference_unchanged,
+// ]
 
 var t = db.jstests_plan_cache_shell_helpers;
 t.drop();
diff --git a/jstests/core/startup_log.js b/jstests/core/startup_log.js
index 3b0cbe3464d..c73013d1744 100644
--- a/jstests/core/startup_log.js
+++ b/jstests/core/startup_log.js
@@ -1,101 +1,108 @@
-load('jstests/aggregation/extras/utils.js');

-

-(function() {

-    'use strict';

-

-    // Check that smallArray is entirely contained by largeArray

-    // returns false if a member of smallArray is not in largeArray

-    function arrayIsSubset(smallArray, largeArray) {

-        for (var i = 0; i < smallArray.length; i++) {

-            if (!Array.contains(largeArray, smallArray[i])) {

-                print("Could not find " + smallArray[i] + " in largeArray");

-                return false;

-            }

-        }

-

-        return true;

-    }

-

-    // Test startup_log

-    var stats = db.getSisterDB("local").startup_log.stats();

-    assert(stats.capped);

-

-    var latestStartUpLog =

-        db.getSisterDB("local").startup_log.find().sort({$natural: -1}).limit(1).next();

-    var serverStatus = db._adminCommand("serverStatus");

-    var cmdLine = db._adminCommand("getCmdLineOpts").parsed;

-

-    // Test that the startup log has the expected keys

-    var verbose = false;

-    var expectedKeys =

-        ["_id", "hostname", "startTime", "startTimeLocal", "cmdLine", "pid", "buildinfo"];

-    var keys = Object.keySet(latestStartUpLog);

-    assert(arrayEq(expectedKeys, keys, verbose), 'startup_log keys failed');

-

-    // Tests _id implicitly - should be comprised of host-timestamp

-    // Setup expected startTime and startTimeLocal from the supplied timestamp

-    var _id = latestStartUpLog._id.split('-');  // _id should consist of host-timestamp

-    var _idUptime = _id.pop();

-    var _idHost = _id.join('-');

-    var uptimeSinceEpochRounded = Math.floor(_idUptime / 1000) * 1000;

-    var startTime = new Date(uptimeSinceEpochRounded);  // Expected startTime

-

-    assert.eq(_idHost, latestStartUpLog.hostname, "Hostname doesn't match one from _id");

-    assert.eq(serverStatus.host.split(':')[0],

-              latestStartUpLog.hostname,

-              "Hostname doesn't match one in server status");

-    assert.closeWithinMS(startTime,

-                         latestStartUpLog.startTime,

-                         "StartTime doesn't match one from _id",

-                         2000);  // Expect less than 2 sec delta

-    assert.eq(cmdLine, latestStartUpLog.cmdLine, "cmdLine doesn't match that from getCmdLineOpts");

-    assert.eq(serverStatus.pid, latestStartUpLog.pid, "pid doesn't match that from serverStatus");

-

-    // Test buildinfo

-    var buildinfo = db.runCommand("buildinfo");

-    delete buildinfo.ok;  // Delete extra meta info not in startup_log

-    var isMaster = db._adminCommand("ismaster");

-

-    // Test buildinfo has the expected keys

-    var expectedKeys = [

-        "version",

-        "gitVersion",

-        "allocator",

-        "versionArray",

-        "javascriptEngine",

-        "openssl",

-        "buildEnvironment",

-        "debug",

-        "maxBsonObjectSize",

-        "bits",

-        "modules"

-    ];

-

-    var keys = Object.keySet(latestStartUpLog.buildinfo);

-    // Disabled to check

-    assert(arrayIsSubset(expectedKeys, keys),

-           "buildinfo keys failed! \n expected:\t" + expectedKeys + "\n actual:\t" + keys);

-    assert.eq(buildinfo,

-              latestStartUpLog.buildinfo,

-              "buildinfo doesn't match that from buildinfo command");

-

-    // Test version and version Array

-    var version = latestStartUpLog.buildinfo.version.split('-')[0];

-    var versionArray = latestStartUpLog.buildinfo.versionArray;

-    var versionArrayCleaned = versionArray.slice(0, 3);

-    if (versionArray[3] == -100) {

-        versionArrayCleaned[2] -= 1;

-    }

-

-    assert.eq(serverStatus.version,

-              latestStartUpLog.buildinfo.version,

-              "Mongo version doesn't match that from ServerStatus");

-    assert.eq(

-        version, versionArrayCleaned.join('.'), "version doesn't match that from the versionArray");

-    var jsEngine = latestStartUpLog.buildinfo.javascriptEngine;

-    assert((jsEngine == "none") || jsEngine.startsWith("mozjs"));

-    assert.eq(isMaster.maxBsonObjectSize,

-              latestStartUpLog.buildinfo.maxBsonObjectSize,

-              "maxBsonObjectSize doesn't match one from ismaster");

-

-})();

+/**
+ * This test attempts to read from the "local.startup_log" collection and assert that it has an
+ * entry matching the server's response from the "getCmdLineOpts" command. The former operation may
+ * be routed to a secondary in the replica set, whereas the latter must be routed to the primary.
+ *
+ * @tags: [assumes_read_preference_unchanged]
+ */
+load('jstests/aggregation/extras/utils.js');
+
+(function() {
+    'use strict';
+
+    // Check that smallArray is entirely contained by largeArray
+    // returns false if a member of smallArray is not in largeArray
+    function arrayIsSubset(smallArray, largeArray) {
+        for (var i = 0; i < smallArray.length; i++) {
+            if (!Array.contains(largeArray, smallArray[i])) {
+                print("Could not find " + smallArray[i] + " in largeArray");
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    // Test startup_log
+    var stats = db.getSisterDB("local").startup_log.stats();
+    assert(stats.capped);
+
+    var latestStartUpLog =
+        db.getSisterDB("local").startup_log.find().sort({$natural: -1}).limit(1).next();
+    var serverStatus = db._adminCommand("serverStatus");
+    var cmdLine = db._adminCommand("getCmdLineOpts").parsed;
+
+    // Test that the startup log has the expected keys
+    var verbose = false;
+    var expectedKeys =
+        ["_id", "hostname", "startTime", "startTimeLocal", "cmdLine", "pid", "buildinfo"];
+    var keys = Object.keySet(latestStartUpLog);
+    assert(arrayEq(expectedKeys, keys, verbose), 'startup_log keys failed');
+
+    // Tests _id implicitly - should be comprised of host-timestamp
+    // Setup expected startTime and startTimeLocal from the supplied timestamp
+    var _id = latestStartUpLog._id.split('-');  // _id should consist of host-timestamp
+    var _idUptime = _id.pop();
+    var _idHost = _id.join('-');
+    var uptimeSinceEpochRounded = Math.floor(_idUptime / 1000) * 1000;
+    var startTime = new Date(uptimeSinceEpochRounded);  // Expected startTime
+
+    assert.eq(_idHost, latestStartUpLog.hostname, "Hostname doesn't match one from _id");
+    assert.eq(serverStatus.host.split(':')[0],
+              latestStartUpLog.hostname,
+              "Hostname doesn't match one in server status");
+    assert.closeWithinMS(startTime,
+                         latestStartUpLog.startTime,
+                         "StartTime doesn't match one from _id",
+                         2000);  // Expect less than 2 sec delta
+    assert.eq(cmdLine, latestStartUpLog.cmdLine, "cmdLine doesn't match that from getCmdLineOpts");
+    assert.eq(serverStatus.pid, latestStartUpLog.pid, "pid doesn't match that from serverStatus");
+
+    // Test buildinfo
+    var buildinfo = db.runCommand("buildinfo");
+    delete buildinfo.ok;  // Delete extra meta info not in startup_log
+    var isMaster = db._adminCommand("ismaster");
+
+    // Test buildinfo has the expected keys
+    var expectedKeys = [
+        "version",
+        "gitVersion",
+        "allocator",
+        "versionArray",
+        "javascriptEngine",
+        "openssl",
+        "buildEnvironment",
+        "debug",
+        "maxBsonObjectSize",
+        "bits",
+        "modules"
+    ];
+
+    var keys = Object.keySet(latestStartUpLog.buildinfo);
+    // Disabled to check
+    assert(arrayIsSubset(expectedKeys, keys),
+           "buildinfo keys failed! \n expected:\t" + expectedKeys + "\n actual:\t" + keys);
+    assert.eq(buildinfo,
+              latestStartUpLog.buildinfo,
+              "buildinfo doesn't match that from buildinfo command");
+
+    // Test version and version Array
+    var version = latestStartUpLog.buildinfo.version.split('-')[0];
+    var versionArray = latestStartUpLog.buildinfo.versionArray;
+    var versionArrayCleaned = versionArray.slice(0, 3);
+    if (versionArray[3] == -100) {
+        versionArrayCleaned[2] -= 1;
+    }
+
+    assert.eq(serverStatus.version,
+              latestStartUpLog.buildinfo.version,
+              "Mongo version doesn't match that from ServerStatus");
+    assert.eq(
+        version, versionArrayCleaned.join('.'), "version doesn't match that from the versionArray");
+    var jsEngine = latestStartUpLog.buildinfo.javascriptEngine;
+    assert((jsEngine == "none") || jsEngine.startsWith("mozjs"));
+    assert.eq(isMaster.maxBsonObjectSize,
+              latestStartUpLog.buildinfo.maxBsonObjectSize,
+              "maxBsonObjectSize doesn't match one from ismaster");
+
+})();
diff --git a/jstests/core/top.js b/jstests/core/top.js
index 819b41b0981..3d98f5a7b2d 100644
--- a/jstests/core/top.js
+++ b/jstests/core/top.js
@@ -1,5 +1,11 @@
 /**
  * 1. check top numbers are correct
+ *
+ * This test attempts to perform read operations and get statistics using the top command. The
+ * former operation may be routed to a secondary in the replica set, whereas the latter must be
+ * routed to the primary.
+ *
+ * @tags: [assumes_read_preference_unchanged]
  */
 (function() {
     load("jstests/libs/stats.js");
diff --git a/jstests/core/views/views_all_commands.js b/jstests/core/views/views_all_commands.js
index 0115672dcda..3d90bd24d32 100644
--- a/jstests/core/views/views_all_commands.js
+++ b/jstests/core/views/views_all_commands.js
@@ -294,14 +294,19 @@
             },
             command: function(conn) {
                 // First get and check a partial result for an aggregate command.
-                let aggCmd = {aggregate: "view", pipeline: [], cursor: {batchSize: 2}};
+                let aggCmd = {
+                    aggregate: "view",
+                    pipeline: [{$sort: {_id: 1}}],
+                    cursor: {batchSize: 2}
+                };
                 let res = conn.runCommand(aggCmd);
                 assert.commandWorked(res, aggCmd);
                 let cursor = res.cursor;
                 assert.eq(
                     cursor.ns, "test.view", "expected view namespace in cursor: " + tojson(cursor));
                 let expectedFirstBatch = [{_id: 1}, {_id: 2}];
-                assert.eq(cursor.firstBatch, expectedFirstBatch, "find returned wrong firstBatch");
+                assert.eq(
+                    cursor.firstBatch, expectedFirstBatch, "aggregate returned wrong firstBatch");
 
                 // Then check correct execution of the killCursors command.
                 let killCursorsCmd = {killCursors: "view", cursors: [cursor.id]};
diff --git a/jstests/core/views/views_stats.js b/jstests/core/views/views_stats.js
index 75feb857c9a..22261e9fa81 100644
--- a/jstests/core/views/views_stats.js
+++ b/jstests/core/views/views_stats.js
@@ -1,4 +1,10 @@
 // Test that top and latency histogram statistics are recorded for views.
+//
+// This test attempts to perform write operations and get latency statistics using the $collStats
+// stage. The former operation must be routed to the primary in a replica set, whereas the latter
+// may be routed to a secondary.
+//
+// @tags: [assumes_read_preference_unchanged]
 
 (function() {
     "use strict";
diff --git a/jstests/libs/override_methods/set_read_preference_secondary.js b/jstests/libs/override_methods/set_read_preference_secondary.js
new file mode 100644
index 00000000000..d1d26433c5c
--- /dev/null
+++ b/jstests/libs/override_methods/set_read_preference_secondary.js
@@ -0,0 +1,162 @@
+/**
+ * Use prototype overrides to set read preference to "secondary" when running tests.
+ */
+(function() {
+    "use strict";
+
+    load("jstests/libs/override_methods/override_helpers.js");
+
+    const kReadPreferenceSecondary = {mode: "secondary"};
+    const kCommandsSupportingReadPreference = new Set([
+        "aggregate",
+        "collStats",
+        "count",
+        "dbStats",
+        "distinct",
+        "find",
+        "geoNear",
+        "geoSearch",
+        "group",
+        "mapReduce",
+        "mapreduce",
+        "parallelCollectionScan",
+    ]);
+
+    // This list of cursor-generating commands is incomplete. For example, "listCollections",
+    // "listIndexes", "parallelCollectionScan", and "repairCursor" are all missing from this list.
+    // If we ever add tests that attempt to run getMore or killCursors on cursors generated from
+    // those commands, then we should update the contents of this list and also handle any
+    // differences in the server's response format.
+    const kCursorGeneratingCommands = new Set(["aggregate", "find"]);
+
+    const CursorTracker = (function() {
+        const kNoCursor = new NumberLong(0);
+
+        const connectionsByCursorId = {};
+
+        return {
+            getConnectionUsedForCursor: function getConnectionUsedForCursor(cursorId) {
+                return (cursorId instanceof NumberLong) ? connectionsByCursorId[cursorId]
+                                                        : undefined;
+            },
+
+            setConnectionUsedForCursor: function setConnectionUsedForCursor(cursorId, cursorConn) {
+                if (cursorId instanceof NumberLong &&
+                    !bsonBinaryEqual({_: cursorId}, {_: kNoCursor})) {
+                    connectionsByCursorId[cursorId] = cursorConn;
+                }
+            },
+        };
+    })();
+
+    function runCommandWithReadPreferenceSecondary(
+        conn, dbName, commandName, commandObj, func, makeFuncArgs) {
+        if (typeof commandObj !== "object" || commandObj === null) {
+            return func.apply(conn, makeFuncArgs(commandObj));
+        }
+
+        // If the command is in a wrapped form, then we look for the actual command object inside
+        // the query/$query object.
+        let commandObjUnwrapped = commandObj;
+        if (commandName === "query" || commandName === "$query") {
+            commandObjUnwrapped = commandObj[commandName];
+            commandName = Object.keys(commandObjUnwrapped)[0];
+        }
+
+        if (commandObj[commandName] === "system.profile") {
+            throw new Error("Cowardly refusing to run test with overridden read preference" +
+                            " when it reads from a non-replicated collection: " +
+                            tojson(commandObj));
+        }
+
+        if (conn.isReplicaSetConnection()) {
+            // When a "getMore" or "killCursors" command is issued on a replica set connection, we
+            // attempt to automatically route the command to the server the cursor(s) were
+            // originally established on. This makes it possible to use the
+            // set_read_preference_secondary.js override without needing to update calls of
+            // DB#runCommand() to explicitly track the connection that was used. If the connection
+            // is actually a direct connection to a mongod or mongos process, or if the cursor id
+            // cannot be found in the CursorTracker, then we'll fall back to using DBClientRS's
+            // server selection and send the operation to the current primary. It is possible that
+            // the test is trying to exercise the behavior around when an unknown cursor id is sent
+            // to the server.
+            if (commandName === "getMore") {
+                const cursorId = commandObjUnwrapped[commandName];
+                const cursorConn = CursorTracker.getConnectionUsedForCursor(cursorId);
+                if (cursorConn !== undefined) {
+                    return func.apply(cursorConn, makeFuncArgs(commandObj));
+                }
+            } else if (commandName === "killCursors") {
+                const cursorIds = commandObjUnwrapped.cursors;
+                if (Array.isArray(cursorIds)) {
+                    let cursorConn;
+
+                    for (let cursorId of cursorIds) {
+                        const otherCursorConn = CursorTracker.getConnectionUsedForCursor(cursorId);
+                        if (cursorConn === undefined) {
+                            cursorConn = otherCursorConn;
+                        } else if (otherCursorConn !== undefined) {
+                            // We set 'cursorConn' back to undefined and break out of the loop so
+                            // that we don't attempt to automatically route the "killCursors"
+                            // command when there are cursors from different servers.
+                            cursorConn = undefined;
+                            break;
+                        }
+                    }
+
+                    if (cursorConn !== undefined) {
+                        return func.apply(cursorConn, makeFuncArgs(commandObj));
+                    }
+                }
+            }
+        }
+
+        let shouldForceReadPreference = kCommandsSupportingReadPreference.has(commandName);
+        if (OverrideHelpers.isAggregationWithOutStage(commandName, commandObjUnwrapped)) {
+            // An aggregation with a $out stage must be sent to the primary.
+            shouldForceReadPreference = false;
+        } else if ((commandName === "mapReduce" || commandName === "mapreduce") &&
+                   !OverrideHelpers.isMapReduceWithInlineOutput(commandName, commandObjUnwrapped)) {
+            // A map-reduce operation with non-inline output must be sent to the primary.
+            shouldForceReadPreference = false;
+        }
+
+        if (shouldForceReadPreference) {
+            if (commandObj === commandObjUnwrapped) {
+                // We wrap the command object using a "query" field rather than a "$query" field to
+                // match the implementation of DB.prototype._attachReadPreferenceToCommand().
+                commandObj = {query: commandObj};
+            } else {
+                // We create a copy of 'commandObj' to avoid mutating the parameter the caller
+                // specified.
+                commandObj = Object.assign({}, commandObj);
+            }
+
+            if (commandObj.hasOwnProperty("$readPreference") &&
+                !bsonBinaryEqual({_: commandObj.$readPreference}, {_: kReadPreferenceSecondary})) {
+                throw new Error("Cowardly refusing to override read preference of command: " +
+                                tojson(commandObj));
+            }
+
+            commandObj.$readPreference = kReadPreferenceSecondary;
+        }
+
+        const serverResponse = func.apply(conn, makeFuncArgs(commandObj));
+
+        if (conn.isReplicaSetConnection() && kCursorGeneratingCommands.has(commandName) &&
+            serverResponse.ok === 1 && serverResponse.hasOwnProperty("cursor")) {
+            // We associate the cursor id returned by the server with the connection that was used
+            // to establish it so that we can attempt to automatically route subsequent "getMore"
+            // and "killCursors" commands.
+            CursorTracker.setConnectionUsedForCursor(serverResponse.cursor.id,
+                                                     serverResponse._mongo);
+        }
+
+        return serverResponse;
+    }
+
+    OverrideHelpers.prependOverrideInParallelShell(
+        "jstests/libs/override_methods/set_read_preference_secondary.js");
+
+    OverrideHelpers.overrideRunCommand(runCommandWithReadPreferenceSecondary);
+})();