SERVER-30683 Support failovers in ReplicaSetFixture

41 files changed, 228 insertions, 206 deletions

diff --git a/buildscripts/resmokeconfig/suites/aggregation_read_concern_majority_passthrough.yml b/buildscripts/resmokeconfig/suites/aggregation_read_concern_majority_passthrough.yml
index d0c7ca7ac6a..1344f26cec0 100644
--- a/buildscripts/resmokeconfig/suites/aggregation_read_concern_majority_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/aggregation_read_concern_majority_passthrough.yml
@@ -39,7 +39,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       enableMajorityReadConcern: ''
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/aggregation_sharded_collections_passthrough.yml b/buildscripts/resmokeconfig/suites/aggregation_sharded_collections_passthrough.yml
index c326b8e4875..de8b568eee6 100644
--- a/buildscripts/resmokeconfig/suites/aggregation_sharded_collections_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/aggregation_sharded_collections_passthrough.yml
@@ -49,11 +49,9 @@ executor:
   fixture:
     class: ShardedClusterFixture
     mongos_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
     mongod_options:
-      bind_ip_all: ''
       nopreallocj: ''
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough.yml
index afe6f6a43fc..55d8db5f075 100644
--- a/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough.yml
@@ -185,7 +185,6 @@ executor:
   fixture:
     class: ShardedClusterFixture
     mongos_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
         logComponentVerbosity:
@@ -196,7 +195,6 @@ executor:
             asio: 2
           tracking: 0
     mongod_options:
-      bind_ip_all: ''
       nopreallocj: ''
       enableMajorityReadConcern: ''
       set_parameters:
diff --git a/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough_auth.yml b/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough_auth.yml
index bbdf1f8ab57..02c4a03a93d 100644
--- a/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough_auth.yml
+++ b/buildscripts/resmokeconfig/suites/causally_consistent_jscore_passthrough_auth.yml
@@ -232,7 +232,6 @@ executor:
   fixture:
     class: ShardedClusterFixture
     mongos_options:
-      bind_ip_all: ''
       keyFile: *keyFile
       set_parameters:
         enableTestCommands: 1
@@ -244,7 +243,6 @@ executor:
             asio: 2
           tracking: 0
     mongod_options:
-      bind_ip_all: ''
       nopreallocj: ''
       enableMajorityReadConcern: ''
       auth: ''
diff --git a/buildscripts/resmokeconfig/suites/core.yml b/buildscripts/resmokeconfig/suites/core.yml
index 1156c5e88cb..4aa054a49bb 100644
--- a/buildscripts/resmokeconfig/suites/core.yml
+++ b/buildscripts/resmokeconfig/suites/core.yml
@@ -19,6 +19,5 @@ executor:
   fixture:
     class: MongoDFixture
     mongod_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/integration_tests_replset.yml b/buildscripts/resmokeconfig/suites/integration_tests_replset.yml
index 6ea48b5a55d..92900f32692 100644
--- a/buildscripts/resmokeconfig/suites/integration_tests_replset.yml
+++ b/buildscripts/resmokeconfig/suites/integration_tests_replset.yml
@@ -15,7 +15,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
         numInitialSyncAttempts: 1
diff --git a/buildscripts/resmokeconfig/suites/integration_tests_sharded.yml b/buildscripts/resmokeconfig/suites/integration_tests_sharded.yml
index 2942a01474a..8f7d234bbd8 100644
--- a/buildscripts/resmokeconfig/suites/integration_tests_sharded.yml
+++ b/buildscripts/resmokeconfig/suites/integration_tests_sharded.yml
@@ -12,12 +12,10 @@ executor:
   fixture:
     class: ShardedClusterFixture
     mongod_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
         numInitialSyncAttempts: 1
     mongos_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
     enable_sharding:
diff --git a/buildscripts/resmokeconfig/suites/integration_tests_standalone.yml b/buildscripts/resmokeconfig/suites/integration_tests_standalone.yml
index 1ab54b6e61f..f8d826c5de8 100644
--- a/buildscripts/resmokeconfig/suites/integration_tests_standalone.yml
+++ b/buildscripts/resmokeconfig/suites/integration_tests_standalone.yml
@@ -12,6 +12,5 @@ executor:
   fixture:
     class: MongoDFixture
     mongod_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/json_schema.yml b/buildscripts/resmokeconfig/suites/json_schema.yml
index e886c3bc4b2..a0535172c67 100644
--- a/buildscripts/resmokeconfig/suites/json_schema.yml
+++ b/buildscripts/resmokeconfig/suites/json_schema.yml
@@ -39,6 +39,5 @@ executor:
   fixture:
     class: MongoDFixture
     mongod_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/jstestfuzz_replication.yml b/buildscripts/resmokeconfig/suites/jstestfuzz_replication.yml
index c8073c10b45..b14a7432ea4 100644
--- a/buildscripts/resmokeconfig/suites/jstestfuzz_replication.yml
+++ b/buildscripts/resmokeconfig/suites/jstestfuzz_replication.yml
@@ -28,7 +28,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
         numInitialSyncAttempts: 1
diff --git a/buildscripts/resmokeconfig/suites/jstestfuzz_replication_initsync.yml b/buildscripts/resmokeconfig/suites/jstestfuzz_replication_initsync.yml
index d5c17ffc8f2..5ff2d73f41b 100644
--- a/buildscripts/resmokeconfig/suites/jstestfuzz_replication_initsync.yml
+++ b/buildscripts/resmokeconfig/suites/jstestfuzz_replication_initsync.yml
@@ -24,7 +24,6 @@ executor:
     class: ReplicaSetFixture
     mongod_options:
       oplogSize: 511
-      bind_ip_all: ''
       verbose: ''
       set_parameters:
         logComponentVerbosity:
diff --git a/buildscripts/resmokeconfig/suites/jstestfuzz_replication_resync.yml b/buildscripts/resmokeconfig/suites/jstestfuzz_replication_resync.yml
index 1a39d00cd77..7fdea6e25cd 100644
--- a/buildscripts/resmokeconfig/suites/jstestfuzz_replication_resync.yml
+++ b/buildscripts/resmokeconfig/suites/jstestfuzz_replication_resync.yml
@@ -23,7 +23,6 @@ executor:
     class: ReplicaSetFixture
     mongod_options:
       oplogSize: 511
-      bind_ip_all: ''
       verbose: ''
       set_parameters:
         logComponentVerbosity:
diff --git a/buildscripts/resmokeconfig/suites/jstestfuzz_sharded.yml b/buildscripts/resmokeconfig/suites/jstestfuzz_sharded.yml
index 4f95e982852..d99b98ba75c 100644
--- a/buildscripts/resmokeconfig/suites/jstestfuzz_sharded.yml
+++ b/buildscripts/resmokeconfig/suites/jstestfuzz_sharded.yml
@@ -19,12 +19,10 @@ executor:
     mongos_options:
       set_parameters:
         enableTestCommands: 1
-      bind_ip_all: ''
       verbose: ''
     mongod_options:
       set_parameters:
         enableTestCommands: 1
         numInitialSyncAttempts: 1
       verbose: ''
-      bind_ip_all: ''
     num_shards: 2
diff --git a/buildscripts/resmokeconfig/suites/master_slave_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/master_slave_jscore_passthrough.yml
index 823cd4ef067..f7aefe690fc 100644
--- a/buildscripts/resmokeconfig/suites/master_slave_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/master_slave_jscore_passthrough.yml
@@ -25,7 +25,6 @@ executor:
   fixture:
     class: MasterSlaveFixture
     mongod_options:
-      bind_ip_all: ''
       oplogSize: 511
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/read_concern_linearizable_passthrough.yml b/buildscripts/resmokeconfig/suites/read_concern_linearizable_passthrough.yml
index ae5845f7724..ab655bca294 100644
--- a/buildscripts/resmokeconfig/suites/read_concern_linearizable_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/read_concern_linearizable_passthrough.yml
@@ -96,7 +96,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       oplogSize: 511
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/read_concern_majority_passthrough.yml b/buildscripts/resmokeconfig/suites/read_concern_majority_passthrough.yml
index 73bfa5a27b9..e5afb848e02 100644
--- a/buildscripts/resmokeconfig/suites/read_concern_majority_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/read_concern_majority_passthrough.yml
@@ -93,7 +93,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
         numInitialSyncAttempts: 1
diff --git a/buildscripts/resmokeconfig/suites/replica_sets_initsync_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/replica_sets_initsync_jscore_passthrough.yml
index 9d2017f2e70..2142079d643 100644
--- a/buildscripts/resmokeconfig/suites/replica_sets_initsync_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/replica_sets_initsync_jscore_passthrough.yml
@@ -92,7 +92,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       oplogSize: 511
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/replica_sets_initsync_static_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/replica_sets_initsync_static_jscore_passthrough.yml
index 659e8efaff5..b3e157d86ee 100644
--- a/buildscripts/resmokeconfig/suites/replica_sets_initsync_static_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/replica_sets_initsync_static_jscore_passthrough.yml
@@ -26,7 +26,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       oplogSize: 511
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/replica_sets_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/replica_sets_jscore_passthrough.yml
index 6933e40e1a8..853b409d318 100644
--- a/buildscripts/resmokeconfig/suites/replica_sets_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/replica_sets_jscore_passthrough.yml
@@ -27,7 +27,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       oplogSize: 511
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/replica_sets_kill_secondaries_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/replica_sets_kill_secondaries_jscore_passthrough.yml
index 6b9b3b20347..c64ed9ebb5b 100644
--- a/buildscripts/resmokeconfig/suites/replica_sets_kill_secondaries_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/replica_sets_kill_secondaries_jscore_passthrough.yml
@@ -24,7 +24,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       oplogSize: 511
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/replica_sets_resync_static_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/replica_sets_resync_static_jscore_passthrough.yml
index 27726964c60..90efaa192e6 100644
--- a/buildscripts/resmokeconfig/suites/replica_sets_resync_static_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/replica_sets_resync_static_jscore_passthrough.yml
@@ -27,7 +27,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       oplogSize: 511
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/retryable_writes_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/retryable_writes_jscore_passthrough.yml
index a319397b83b..a98b7222562 100644
--- a/buildscripts/resmokeconfig/suites/retryable_writes_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/retryable_writes_jscore_passthrough.yml
@@ -50,7 +50,6 @@ executor:
   fixture:
     class: ReplicaSetFixture
     mongod_options:
-      bind_ip_all: ''
       oplogSize: 511
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/session_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/session_jscore_passthrough.yml
index c89afbe78cd..c918b66e91f 100644
--- a/buildscripts/resmokeconfig/suites/session_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/session_jscore_passthrough.yml
@@ -20,6 +20,5 @@ executor:
   fixture:
     class: MongoDFixture
     mongod_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/sharded_causally_consistent_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/sharded_causally_consistent_jscore_passthrough.yml
index 2ab418e0bf0..89065f2d07b 100644
--- a/buildscripts/resmokeconfig/suites/sharded_causally_consistent_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/sharded_causally_consistent_jscore_passthrough.yml
@@ -212,7 +212,6 @@ executor:
   fixture:
     class: ShardedClusterFixture
     mongos_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
         logComponentVerbosity:
@@ -221,7 +220,6 @@ executor:
             verbosity: 1
             asio: 2
     mongod_options:
-      bind_ip_all: ''
       nopreallocj: ''
       enableMajorityReadConcern: ''
       set_parameters:
diff --git a/buildscripts/resmokeconfig/suites/sharded_collections_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/sharded_collections_jscore_passthrough.yml
index fae8086dfa5..b8500d3ed36 100644
--- a/buildscripts/resmokeconfig/suites/sharded_collections_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/sharded_collections_jscore_passthrough.yml
@@ -102,7 +102,6 @@ executor:
       set_parameters:
         enableTestCommands: 1
     mongod_options:
-      bind_ip_all: ''
       nopreallocj: ''
       set_parameters:
         enableTestCommands: 1
diff --git a/buildscripts/resmokeconfig/suites/sharding_gle_auth_basics_passthrough.yml b/buildscripts/resmokeconfig/suites/sharding_gle_auth_basics_passthrough.yml
index bfbf8b8e405..5ea71956614 100644
--- a/buildscripts/resmokeconfig/suites/sharding_gle_auth_basics_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/sharding_gle_auth_basics_passthrough.yml
@@ -32,13 +32,11 @@ executor:
   fixture:
     class: ShardedClusterFixture
     mongos_options:
-      bind_ip_all: ''
       keyFile: *keyFile
       set_parameters:
         enableTestCommands: 1
         enableLocalhostAuthBypass: false
     mongod_options:
-      bind_ip_all: ''
       auth: ''
       keyFile: *keyFile
       set_parameters:
diff --git a/buildscripts/resmokeconfig/suites/sharding_jscore_op_query_passthrough.yml b/buildscripts/resmokeconfig/suites/sharding_jscore_op_query_passthrough.yml
index 298476e37ef..1248e6d80ad 100644
--- a/buildscripts/resmokeconfig/suites/sharding_jscore_op_query_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/sharding_jscore_op_query_passthrough.yml
@@ -64,11 +64,9 @@ executor:
   fixture:
     class: ShardedClusterFixture
     mongos_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
     mongod_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
         numInitialSyncAttempts: 1
diff --git a/buildscripts/resmokeconfig/suites/sharding_jscore_passthrough.yml b/buildscripts/resmokeconfig/suites/sharding_jscore_passthrough.yml
index b6b3dde7e5b..c2be25c8e84 100644
--- a/buildscripts/resmokeconfig/suites/sharding_jscore_passthrough.yml
+++ b/buildscripts/resmokeconfig/suites/sharding_jscore_passthrough.yml
@@ -63,11 +63,9 @@ executor:
   fixture:
     class: ShardedClusterFixture
     mongos_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
     mongod_options:
-      bind_ip_all: ''
       set_parameters:
         enableTestCommands: 1
         numInitialSyncAttempts: 1
diff --git a/buildscripts/resmokelib/core/programs.py b/buildscripts/resmokelib/core/programs.py
index aee4e6cf01a..ceef27dbe57 100644
--- a/buildscripts/resmokelib/core/programs.py
+++ b/buildscripts/resmokelib/core/programs.py
@@ -129,11 +129,13 @@ 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, **kwargs):
+def mongo_shell_program(logger, executable=None, connection_string=None, filename=None,
+                        process_kwargs=None, **kwargs):
     """
-    Returns a Process instance that starts a mongo shell with arguments
-    constructed from 'kwargs'.
+    Returns a Process instance that starts a mongo shell with the given connection string and
+    arguments constructed from 'kwargs'.
     """
+    connection_string = utils.default_if_none(config.SHELL_CONN_STRING, connection_string)
 
     executable = utils.default_if_none(executable, config.DEFAULT_MONGO_EXECUTABLE)
     args = [executable]
@@ -191,7 +193,7 @@ def mongo_shell_program(logger, executable=None, filename=None, process_kwargs=N
         eval_sb.append(str(kwargs.pop("eval")))
 
     # Load this file to allow a callback to validate collections before shutting down mongod.
-    eval_sb.append("load('jstests/libs/override_methods/validate_collections_on_shutdown.js')");
+    eval_sb.append("load('jstests/libs/override_methods/validate_collections_on_shutdown.js');")
 
     eval_str = "; ".join(eval_sb)
     args.append("--eval")
@@ -203,7 +205,7 @@ 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 config.SHELL_CONN_STRING is not None:
+    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.
@@ -216,9 +218,8 @@ def mongo_shell_program(logger, executable=None, filename=None, process_kwargs=N
     # Apply the rest of the command line arguments.
     _apply_kwargs(args, kwargs)
 
-
-    if config.SHELL_CONN_STRING is not None:
-        args.append(config.SHELL_CONN_STRING)
+    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/__init__.py b/buildscripts/resmokelib/testing/fixtures/__init__.py
index b1436ae9148..d8c3d8a2b53 100644
--- a/buildscripts/resmokelib/testing/fixtures/__init__.py
+++ b/buildscripts/resmokelib/testing/fixtures/__init__.py
@@ -4,12 +4,12 @@ Fixtures for executing JSTests against.
 
 from __future__ import absolute_import
 
-from .interface import Fixture as _Fixture
+from .interface import NoOpFixture as _NoOpFixture
 from .interface import make_fixture
 from ...utils import autoloader as _autoloader
 
 
-NOOP_FIXTURE_CLASS = _Fixture.REGISTERED_NAME
+NOOP_FIXTURE_CLASS = _NoOpFixture.REGISTERED_NAME
 
 
 # We dynamically load all modules in the fixtures/ package so that any Fixture classes declared
diff --git a/buildscripts/resmokelib/testing/fixtures/interface.py b/buildscripts/resmokelib/testing/fixtures/interface.py
index 2d950461927..6dffa24e430 100644
--- a/buildscripts/resmokelib/testing/fixtures/interface.py
+++ b/buildscripts/resmokelib/testing/fixtures/interface.py
@@ -7,6 +7,7 @@ from __future__ import absolute_import
 import time
 
 import pymongo
+import pymongo.errors
 
 from ... import errors
 from ... import logging
@@ -53,8 +54,6 @@ class Fixture(object):
         self.logger = logger
         self.job_num = job_num
 
-        self.port = None  # Port that the mongo shell should connect to.
-
     def setup(self):
         """
         Creates the fixture.
@@ -115,6 +114,24 @@ class Fixture(object):
         raise NotImplementedError(
             "get_driver_connection_url must be implemented by Fixture subclasses")
 
+    def mongo_client(self, read_preference=pymongo.ReadPreference.PRIMARY, timeout_millis=30000):
+        """
+        Returns a pymongo.MongoClient connecting to this fixture with a read
+        preference of 'read_preference'.
+
+        The PyMongo driver will wait up to 'timeout_millis' milliseconds
+        before concluding that the server is unavailable.
+        """
+
+        kwargs = {"connectTimeoutMS": timeout_millis}
+        if pymongo.version_tuple[0] >= 3:
+            kwargs["serverSelectionTimeoutMS"] = timeout_millis
+            kwargs["connect"] = True
+
+        return pymongo.MongoClient(host=self.get_driver_connection_url(),
+                                   read_preference=read_preference,
+                                   **kwargs)
+
     def __str__(self):
         return "%s (Job #%d)" % (self.__class__.__name__, self.job_num)
 
@@ -166,5 +183,21 @@ class ReplFixture(Fixture):
             except pymongo.errors.ConnectionFailure:
                 remaining = deadline - time.time()
                 if remaining <= 0.0:
-                    raise errors.ServerFailure("Failed to connect to the primary on port %d" %
-                                               self.port)
+                    raise errors.ServerFailure(
+                        "Failed to connect to ".format(self.get_driver_connection_url()))
+
+
+class NoOpFixture(Fixture):
+    """A Fixture implementation that does not start any servers.
+
+    Used when the MongoDB deployment is started by the JavaScript test itself with MongoRunner,
+    ReplSetTest, or ShardingTest.
+    """
+
+    REGISTERED_NAME = "NoOpFixture"
+
+    def get_internal_connection_string(self):
+        return None
+
+    def get_driver_connection_url(self):
+        return None
diff --git a/buildscripts/resmokelib/testing/fixtures/masterslave.py b/buildscripts/resmokelib/testing/fixtures/masterslave.py
index bef701ff8ee..96b4ec5e96b 100644
--- a/buildscripts/resmokelib/testing/fixtures/masterslave.py
+++ b/buildscripts/resmokelib/testing/fixtures/masterslave.py
@@ -5,14 +5,13 @@ Master/slave fixture for executing JSTests against.
 from __future__ import absolute_import
 
 import os.path
-import socket
 
 import pymongo
+import pymongo.errors
 
 from . import interface
 from . import standalone
 from ... import config
-from ... import logging
 from ... import utils
 
 
@@ -47,7 +46,7 @@ class MasterSlaveFixture(interface.ReplFixture):
         dbpath_prefix = utils.default_if_none(config.DBPATH_PREFIX, dbpath_prefix)
         dbpath_prefix = utils.default_if_none(dbpath_prefix, config.DEFAULT_DBPATH_PREFIX)
         self._dbpath_prefix = os.path.join(dbpath_prefix,
-                                           "job%d" % (self.job_num),
+                                           "job{}".format(self.job_num),
                                            config.FIXTURE_SUBDIR)
 
         self.master = None
@@ -57,7 +56,6 @@ class MasterSlaveFixture(interface.ReplFixture):
         if self.master is None:
             self.master = self._new_mongod_master()
         self.master.setup()
-        self.port = self.master.port
 
         if self.slave is None:
             self.slave = self._new_mongod_slave()
@@ -69,7 +67,7 @@ class MasterSlaveFixture(interface.ReplFixture):
 
         # Do a replicated write to ensure that the slave has finished with its initial sync before
         # starting to run any tests.
-        client = utils.new_mongo_client(self.port)
+        client = self.master.mongo_client()
 
         # Keep retrying this until it times out waiting for replication.
         def insert_fn(remaining_secs):
@@ -158,7 +156,7 @@ 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)
 
diff --git a/buildscripts/resmokelib/testing/fixtures/replicaset.py b/buildscripts/resmokelib/testing/fixtures/replicaset.py
index 54e5c2fe52c..025ce257a7b 100644
--- a/buildscripts/resmokelib/testing/fixtures/replicaset.py
+++ b/buildscripts/resmokelib/testing/fixtures/replicaset.py
@@ -8,11 +8,12 @@ import os.path
 import time
 
 import pymongo
+import pymongo.errors
 
 from . import interface
 from . import standalone
 from ... import config
-from ... import logging
+from ... import errors
 from ... import utils
 
 
@@ -36,7 +37,8 @@ class ReplicaSetFixture(interface.ReplFixture):
                  write_concern_majority_journal_default=None,
                  auth_options=None,
                  replset_config_options=None,
-                 voting_secondaries=True):
+                 voting_secondaries=True,
+                 all_nodes_electable=False):
 
         interface.ReplFixture.__init__(self, logger, job_num)
 
@@ -49,6 +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.all_nodes_electable = all_nodes_electable
 
         # 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
@@ -60,7 +63,7 @@ class ReplicaSetFixture(interface.ReplFixture):
             dbpath_prefix = utils.default_if_none(config.DBPATH_PREFIX, dbpath_prefix)
             dbpath_prefix = utils.default_if_none(dbpath_prefix, config.DEFAULT_DBPATH_PREFIX)
             self._dbpath_prefix = os.path.join(dbpath_prefix,
-                                               "job%d" % (self.job_num),
+                                               "job{}".format(self.job_num),
                                                config.FIXTURE_SUBDIR)
 
         self.nodes = []
@@ -87,18 +90,17 @@ class ReplicaSetFixture(interface.ReplFixture):
             self.initial_sync_node.setup()
             self.initial_sync_node.await_ready()
 
-        self.port = self.get_primary().port
-
         # We need only to wait to connect to the first node of the replica set because we first
         # initiate it as a single node replica set.
-        self.get_primary().await_ready()
+        self.nodes[0].await_ready()
 
         # Initiate the replica set.
         members = []
         for (i, node) in enumerate(self.nodes):
             member_info = {"_id": i, "host": node.get_internal_connection_string()}
             if i > 0:
-                member_info["priority"] = 0
+                if not self.all_nodes_electable:
+                    member_info["priority"] = 0
                 if i >= 7 or not self.voting_secondaries:
                     # Only 7 nodes in a replica set can vote, so the other members must still be
                     # non-voting when this fixture is configured to have voting secondaries.
@@ -112,7 +114,7 @@ class ReplicaSetFixture(interface.ReplFixture):
                             "votes": 0})
 
         config = {"_id": self.replset_name}
-        client = utils.new_mongo_client(port=self.port)
+        client = self.nodes[0].mongo_client()
 
         if self.auth_options is not None:
             auth_db = client[self.auth_options["authenticationDatabase"]]
@@ -146,10 +148,10 @@ class ReplicaSetFixture(interface.ReplFixture):
         self._configure_repl_set(client, {"replSetInitiate": config})
         self._await_primary()
 
-        if self.get_secondaries():
+        if self.nodes[1:]:
             # Wait to connect to each of the secondaries before running the replSetReconfig
             # command.
-            for node in self.get_secondaries():
+            for node in self.nodes[1:]:
                 node.await_ready()
             config["version"] = 2
             config["members"] = members
@@ -184,24 +186,28 @@ class ReplicaSetFixture(interface.ReplFixture):
 
     def _await_primary(self):
         # Wait for the primary to be elected.
-        client = utils.new_mongo_client(port=self.port)
+        # Since this method is called at startup we expect the first node to be primary even when
+        # self.all_nodes_electable is True.
+        primary = self.nodes[0]
+        client = primary.mongo_client()
         while True:
-            self.logger.info("Waiting for primary on port %d to be elected.", self.port)
+            self.logger.info("Waiting for primary on port %d to be elected.", primary.port)
             is_master = client.admin.command("isMaster")["ismaster"]
             if is_master:
                 break
             time.sleep(0.1)  # Wait a little bit before trying again.
-        self.logger.info("Primary on port %d successfully elected.", self.port)
+        self.logger.info("Primary on port %d successfully elected.", primary.port)
 
     def _await_secondaries(self):
         # Wait for the secondaries to become available.
-        secondaries = self.get_secondaries()
+        # Since this method is called at startup we expect the nodes 1 to n to be secondaries even
+        # when self.all_nodes_electable is True.
+        secondaries = self.nodes[1:]
         if self.initial_sync_node:
             secondaries.append(self.initial_sync_node)
 
         for secondary in secondaries:
-            client = utils.new_mongo_client(port=secondary.port,
-                                            read_preference=pymongo.ReadPreference.SECONDARY)
+            client = secondary.mongo_client(read_preference=pymongo.ReadPreference.SECONDARY)
             while True:
                 self.logger.info("Waiting for secondary on port %d to become available.",
                                  secondary.port)
@@ -241,13 +247,38 @@ class ReplicaSetFixture(interface.ReplFixture):
 
         return running
 
-    def get_primary(self):
-        # The primary is always the first element of the 'nodes' list because all other members of
-        # the replica set are configured with priority=0.
-        return self.nodes[0]
+    def get_primary(self, timeout_secs=30):
+        if not self.all_nodes_electable:
+            # The primary is always the first element of the 'nodes' list because all other members
+            # of the replica set are configured with priority=0.
+            return self.nodes[0]
+
+        start = time.time()
+        clients = {}
+        while True:
+            for node in self.nodes:
+                self._check_get_primary_timeout(start, timeout_secs)
+                client = clients.get(node.port)
+                if not client:
+                    client = node.mongo_client()
+                    clients[node.port] = client
+                is_master = client.admin.command("isMaster")["ismaster"]
+                if is_master:
+                    self.logger.info("The node on port %d is primary of replica set '%s'",
+                                     node.port, self.replset_name)
+                    return node
+
+    def _check_get_primary_timeout(self, start, timeout_secs):
+        now = time.time()
+        if (now - start) >= timeout_secs:
+            msg = "Timed out while waiting for a primary for replica set '{}'.".format(
+                self.replset_name)
+            self.logger.error(msg)
+            raise errors.ServerFailure(msg)
 
     def get_secondaries(self):
-        return self.nodes[1:]
+        primary = self.get_primary()
+        return [node for node in self.nodes if node.port != primary.port]
 
     def get_initial_sync_node(self):
         return self.initial_sync_node
@@ -261,7 +292,7 @@ class ReplicaSetFixture(interface.ReplFixture):
         mongod_logger = self._get_logger_for_mongod(index)
         mongod_options = self.mongod_options.copy()
         mongod_options["replSet"] = replset_name
-        mongod_options["dbpath"] = os.path.join(self._dbpath_prefix, "node%d" % (index))
+        mongod_options["dbpath"] = os.path.join(self._dbpath_prefix, "node{}".format(index))
 
         return standalone.MongoDFixture(mongod_logger,
                                         self.job_num,
@@ -275,13 +306,15 @@ class ReplicaSetFixture(interface.ReplFixture):
         sync member of a replica-set.
         """
 
-        if index == 0:
-            node_name = "primary"
-        elif index == self.initial_sync_node_idx:
+        if index == self.initial_sync_node_idx:
             node_name = "initsync"
+        elif self.all_nodes_electable:
+            node_name = "node{}".format(index)
+        elif index == 0:
+            node_name = "primary"
         else:
             suffix = str(index - 1) if self.num_nodes > 2 else ""
-            node_name = "secondary%s" % suffix
+            node_name = "secondary{}".format(suffix)
 
         return self.logger.new_fixture_node_logger(node_name)
 
@@ -298,8 +331,14 @@ class ReplicaSetFixture(interface.ReplFixture):
         if self.replset_name is None:
             raise ValueError("Must call setup() before calling get_driver_connection_url()")
 
-        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
+        if self.all_nodes_electable:
+            # 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 2c65c70e5a8..e9104e114ca 100644
--- a/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
+++ b/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
@@ -10,6 +10,7 @@ import socket
 import time
 
 import pymongo
+import pymongo.errors
 
 from . import interface
 from . import standalone
@@ -115,9 +116,8 @@ class ShardedClusterFixture(interface.Fixture):
 
         # Wait for the mongos
         self.mongos.await_ready()
-        self.port = self.mongos.port
 
-        client = utils.new_mongo_client(port=self.port)
+        client = self.mongo_client()
         if self.auth_options is not None:
             auth_db = client[self.auth_options["authenticationDatabase"]]
             auth_db.authenticate(self.auth_options["username"],
@@ -184,7 +184,7 @@ class ShardedClusterFixture(interface.Fixture):
         if self.mongos is None:
             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()
@@ -261,16 +261,11 @@ class ShardedClusterFixture(interface.Fixture):
         mongos_logger = self.logger.new_fixture_node_logger("mongos")
 
         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,
@@ -312,6 +307,7 @@ class _MongoSFixture(interface.Fixture):
         self.mongos_options = utils.default_if_none(mongos_options, {}).copy()
 
         self.mongos = None
+        self.port = None
 
     def setup(self):
         if "port" not in self.mongos_options:
@@ -346,7 +342,7 @@ class _MongoSFixture(interface.Fixture):
 
             try:
                 # Use a shorter connection timeout to more closely satisfy the requested deadline.
-                client = utils.new_mongo_client(self.port, timeout_millis=500)
+                client = self.mongo_client(timeout_millis=500)
                 client.admin.command("ping")
                 break
             except pymongo.errors.ConnectionFailure:
@@ -391,3 +387,12 @@ 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 a657959259f..1fd8a80c7e1 100644
--- a/buildscripts/resmokelib/testing/fixtures/standalone.py
+++ b/buildscripts/resmokelib/testing/fixtures/standalone.py
@@ -7,10 +7,10 @@ from __future__ import absolute_import
 import os
 import os.path
 import shutil
-import socket
 import time
 
 import pymongo
+import pymongo.errors
 
 from . import interface
 from ... import config
@@ -53,11 +53,12 @@ class MongoDFixture(interface.Fixture):
             dbpath_prefix = utils.default_if_none(config.DBPATH_PREFIX, dbpath_prefix)
             dbpath_prefix = utils.default_if_none(dbpath_prefix, config.DEFAULT_DBPATH_PREFIX)
             self.mongod_options["dbpath"] = os.path.join(dbpath_prefix,
-                                                         "job%d" % (self.job_num),
+                                                         "job{}".format(self.job_num),
                                                          config.FIXTURE_SUBDIR)
         self._dbpath = self.mongod_options["dbpath"]
 
         self.mongod = None
+        self.port = None
 
     def setup(self):
         if not self.preserve_dbpath:
@@ -96,20 +97,21 @@ class MongoDFixture(interface.Fixture):
             # Check whether the mongod exited for some reason.
             exit_code = self.mongod.poll()
             if exit_code is not None:
-                raise errors.ServerFailure("Could not connect to mongod on port %d, process ended"
-                                           " unexpectedly with code %d." % (self.port, exit_code))
+                raise errors.ServerFailure("Could not connect to mongod on port {}, process ended"
+                                           " unexpectedly with code {}.".format(
+                                                self.port, exit_code))
 
             try:
                 # Use a shorter connection timeout to more closely satisfy the requested deadline.
-                client = utils.new_mongo_client(self.port, timeout_millis=500)
+                client = self.mongo_client(timeout_millis=500)
                 client.admin.command("ping")
                 break
             except pymongo.errors.ConnectionFailure:
                 remaining = deadline - time.time()
                 if remaining <= 0.0:
                     raise errors.ServerFailure(
-                        "Failed to connect to mongod on port %d after %d seconds"
-                        % (self.port, MongoDFixture.AWAIT_READY_TIMEOUT_SECS))
+                        "Failed to connect to mongod on port {} after {} seconds".format(
+                            self.port, MongoDFixture.AWAIT_READY_TIMEOUT_SECS))
 
                 self.logger.info("Waiting to connect to mongod on port %d.", self.port)
                 time.sleep(0.1)  # Wait a little bit before trying again.
@@ -151,7 +153,7 @@ class MongoDFixture(interface.Fixture):
         if self.mongod is None:
             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/hooks/initialsync.py b/buildscripts/resmokelib/testing/hooks/initialsync.py
index 1b99d766622..20b422bccb3 100644
--- a/buildscripts/resmokelib/testing/hooks/initialsync.py
+++ b/buildscripts/resmokelib/testing/hooks/initialsync.py
@@ -69,7 +69,7 @@ class BackgroundInitialSync(jsfile.JsCustomBehavior):
     def _after_test_impl(self, test, test_report, description):
         self.tests_run += 1
         sync_node = self.fixture.get_initial_sync_node()
-        sync_node_conn = utils.new_mongo_client(port=sync_node.port)
+        sync_node_conn = sync_node.mongo_client()
 
         # If it's been 'n' tests so far, wait for the initial sync node to finish syncing.
         if self.tests_run >= self.n:
@@ -163,7 +163,7 @@ class IntermediateInitialSync(jsfile.JsCustomBehavior):
 
     def _after_test_impl(self, test, test_report, description):
         sync_node = self.fixture.get_initial_sync_node()
-        sync_node_conn = utils.new_mongo_client(port=sync_node.port)
+        sync_node_conn = sync_node.mongo_client()
 
         if self.use_resync:
             self.hook_test_case.logger.info("Calling resync on initial sync node...")
diff --git a/buildscripts/resmokelib/testing/hooks/periodic_kill_secondaries.py b/buildscripts/resmokelib/testing/hooks/periodic_kill_secondaries.py
index dc19f05f26e..ecbb3969243 100644
--- a/buildscripts/resmokelib/testing/hooks/periodic_kill_secondaries.py
+++ b/buildscripts/resmokelib/testing/hooks/periodic_kill_secondaries.py
@@ -19,7 +19,6 @@ from ..fixtures import interface as fixture
 from ..fixtures import replicaset
 from ..testcases import interface as testcase
 from ... import errors
-from ... import utils
 
 
 class PeriodicKillSecondaries(interface.CustomBehavior):
@@ -31,19 +30,18 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
 
     DEFAULT_PERIOD_SECS = 30
 
-    def __init__(self, hook_logger, fixture, period_secs=DEFAULT_PERIOD_SECS):
-        if not isinstance(fixture, replicaset.ReplicaSetFixture):
-            raise TypeError("%s either does not support replication or does not support writing to"
-                            " its oplog early"
-                            % (fixture.__class__.__name__))
+    def __init__(self, hook_logger, rs_fixture, period_secs=DEFAULT_PERIOD_SECS):
+        if not isinstance(rs_fixture, replicaset.ReplicaSetFixture):
+            raise TypeError("{} either does not support replication or does not support writing to"
+                            " its oplog early".format(rs_fixture.__class__.__name__))
 
-        if fixture.num_nodes <= 1:
+        if rs_fixture.num_nodes <= 1:
             raise ValueError("PeriodicKillSecondaries requires the replica set to contain at least"
                              " one secondary")
 
         description = ("PeriodicKillSecondaries (kills the secondary after running tests for a"
                        " configurable period of time)")
-        interface.CustomBehavior.__init__(self, hook_logger, fixture, description)
+        interface.CustomBehavior.__init__(self, hook_logger, rs_fixture, description)
 
         self._period_secs = period_secs
         self._start_time = None
@@ -59,20 +57,10 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
             # The "rsSyncApplyStop" failpoint is already enabled.
             return
 
-        # Enable the "rsSyncApplyStop" failpoint on each of the secondaries to prevent them from
-        # applying any oplog entries while the test is running.
         for secondary in self.fixture.get_secondaries():
-            client = utils.new_mongo_client(port=secondary.port)
-            try:
-                client.admin.command(bson.SON([
-                    ("configureFailPoint", "rsSyncApplyStop"),
-                    ("mode", "alwaysOn")]))
-            except pymongo.errors.OperationFailure as err:
-                self.logger.exception(
-                    "Unable to disable oplog application on the mongod on port %d", secondary.port)
-                raise errors.ServerFailure(
-                    "Unable to disable oplog application on the mongod on port %d: %s"
-                    % (secondary.port, err.args[0]))
+            # Enable the "rsSyncApplyStop" failpoint on the secondary to prevent them from
+            # applying any oplog entries while the test is running.
+            self._enable_rssyncapplystop(secondary)
 
         self._start_time = time.time()
 
@@ -91,7 +79,7 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
         self.hook_test_case = testcase.TestCase(
             self.logger,
             "Hook",
-            "%s:%s" % (self._last_test_name, self.logger_name))
+            "{}:{}".format(self._last_test_name, self.logger_name))
         interface.CustomBehavior.start_dynamic_test(self.hook_test_case, test_report)
 
         try:
@@ -127,19 +115,7 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
         for secondary in self.fixture.get_secondaries():
             # Disable the "rsSyncApplyStop" failpoint on the secondary to have it resume applying
             # oplog entries.
-            for secondary in self.fixture.get_secondaries():
-                client = utils.new_mongo_client(port=secondary.port)
-                try:
-                    client.admin.command(bson.SON([
-                        ("configureFailPoint", "rsSyncApplyStop"),
-                        ("mode", "off")]))
-                except pymongo.errors.OperationFailure as err:
-                    self.logger.exception(
-                        "Unable to re-enable oplog application on the mongod on port %d",
-                        secondary.port)
-                    raise errors.ServerFailure(
-                        "Unable to re-enable oplog application on the mongod on port %d: %s"
-                        % (secondary.port, err.args[0]))
+            self._disable_rssyncapplystop(secondary)
 
             # Wait a little bit for the secondary to start apply oplog entries so that we are more
             # likely to kill the mongod process while it is partway into applying a batch.
@@ -149,12 +125,11 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
             # we still detect some cases in which the secondary has already crashed.
             if not secondary.is_running():
                 raise errors.ServerFailure(
-                    "mongod on port %d was expected to be running in"
-                    " PeriodicKillSecondaries.after_test(), but wasn't."
-                    % (secondary.port))
+                    "mongod on port {} was expected to be running in"
+                    " PeriodicKillSecondaries.after_test(), but wasn't.".format(secondary.port))
 
             self.hook_test_case.logger.info(
-                "Killing the secondary on port %d..." % (secondary.port))
+                "Killing the secondary on port %d...", secondary.port)
             secondary.mongod.stop(kill=True)
 
         # Teardown may or may not be considered a success as a result of killing a secondary, so we
@@ -179,7 +154,8 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
             teardown_success = secondary.teardown()
             if not teardown_success:
                 raise errors.ServerFailure(
-                    "%s did not exit cleanly after reconciling the end of its oplog" % (secondary))
+                    "{} did not exit cleanly after reconciling the end of its oplog".format(
+                        secondary))
 
         self.hook_test_case.logger.info(
             "Starting the fixture back up again with its data files intact...")
@@ -217,8 +193,7 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
         teardown_success = self.fixture.teardown()
         if not teardown_success:
             raise errors.ServerFailure(
-                "%s did not exit cleanly after verifying data consistency"
-                % (self.fixture))
+                "{} did not exit cleanly after verifying data consistency".format(self.fixture))
 
         self.hook_test_case.logger.info("Starting the fixture back up again...")
         self.fixture.setup()
@@ -232,7 +207,7 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
             secondary.setup()
             secondary.await_ready()
 
-            client = utils.new_mongo_client(port=secondary.port)
+            client = secondary.mongo_client()
             minvalid_doc = client.local["replset.minvalid"].find_one()
 
             latest_oplog_doc = client.local["oplog.rs"].find_one(
@@ -261,26 +236,27 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
 
                 if not begin_ts <= minvalid_ts:
                     raise errors.ServerFailure(
-                        "The condition begin <= minValid (%s <= %s) doesn't hold: minValid"
-                        " document=%s, latest oplog entry=%s"
-                        % (begin_ts, minvalid_ts, minvalid_doc, latest_oplog_doc))
+                        "The condition begin <= minValid ({} <= {}) doesn't hold: minValid"
+                        " document={}, latest oplog entry={}".format(
+                            begin_ts, minvalid_ts, minvalid_doc, latest_oplog_doc))
 
                 if not minvalid_ts <= oplog_delete_point_ts:
                     raise errors.ServerFailure(
-                        "The condition minValid <= oplogDeletePoint (%s <= %s) doesn't hold:"
-                        " minValid document=%s, latest oplog entry=%s"
-                        % (minvalid_ts, oplog_delete_point_ts, minvalid_doc, latest_oplog_doc))
+                        "The condition minValid <= oplogDeletePoint ({} <= {}) doesn't hold:"
+                        " minValid document={}, latest oplog entry={}".format(
+                            minvalid_ts, oplog_delete_point_ts, minvalid_doc, latest_oplog_doc))
 
                 if not minvalid_ts <= latest_oplog_entry_ts:
                     raise errors.ServerFailure(
-                        "The condition minValid <= top of oplog (%s <= %s) doesn't hold: minValid"
-                        " document=%s, latest oplog entry=%s"
-                        % (minvalid_ts, latest_oplog_entry_ts, minvalid_doc, latest_oplog_doc))
+                        "The condition minValid <= top of oplog ({} <= {}) doesn't hold: minValid"
+                        " document={}, latest oplog entry={}".format(
+                            minvalid_ts, latest_oplog_entry_ts, minvalid_doc, latest_oplog_doc))
 
             teardown_success = secondary.teardown()
             if not teardown_success:
                 raise errors.ServerFailure(
-                    "%s did not exit cleanly after being started up as a standalone" % (secondary))
+                    "{} did not exit cleanly after being started up as a standalone".format(
+                        secondary))
         except pymongo.errors.OperationFailure as err:
             self.hook_test_case.logger.exception(
                 "Failed to read the minValid document or the latest oplog entry from the mongod on"
@@ -288,14 +264,13 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
                 secondary.port)
             raise errors.ServerFailure(
                 "Failed to read the minValid document or the latest oplog entry from the mongod on"
-                " port %d: %s"
-                % (secondary.port, err.args[0]))
+                " port {}: {}".format(secondary.port, err.args[0]))
         finally:
             # Set the secondary's options back to their original values.
             secondary.mongod_options["replSet"] = replset_name
 
     def _await_secondary_state(self, secondary):
-        client = utils.new_mongo_client(port=secondary.port)
+        client = secondary.mongo_client()
         try:
             client.admin.command(bson.SON([
                 ("replSetTest", 1),
@@ -307,5 +282,36 @@ class PeriodicKillSecondaries(interface.CustomBehavior):
                 secondary.port,
                 fixture.ReplFixture.AWAIT_REPL_TIMEOUT_MINS * 60)
             raise errors.ServerFailure(
-                "mongod on port %d failed to reach state SECONDARY after %d seconds: %s"
-                % (secondary.port, fixture.ReplFixture.AWAIT_REPL_TIMEOUT_MINS * 60, err.args[0]))
+                "mongod on port {} failed to reach state SECONDARY after {} seconds: {}".format(
+                    secondary.port, fixture.ReplFixture.AWAIT_REPL_TIMEOUT_MINS * 60, err.args[0]))
+
+    def _enable_rssyncapplystop(self, secondary):
+        # Enable the "rsSyncApplyStop" failpoint on the secondary to prevent them from
+        # applying any oplog entries while the test is running.
+        client = secondary.mongo_client()
+        try:
+            client.admin.command(bson.SON([
+                ("configureFailPoint", "rsSyncApplyStop"),
+                ("mode", "alwaysOn")]))
+        except pymongo.errors.OperationFailure as err:
+            self.logger.exception(
+                "Unable to disable oplog application on the mongod on port %d", secondary.port)
+            raise errors.ServerFailure(
+                "Unable to disable oplog application on the mongod on port {}: {}".format(
+                    secondary.port, err.args[0]))
+
+    def _disable_rssyncapplystop(self, secondary):
+        # Disable the "rsSyncApplyStop" failpoint on the secondary to have it resume applying
+        # oplog entries.
+        client = secondary.mongo_client()
+        try:
+            client.admin.command(bson.SON([
+                ("configureFailPoint", "rsSyncApplyStop"),
+                ("mode", "off")]))
+        except pymongo.errors.OperationFailure as err:
+            self.logger.exception(
+                "Unable to re-enable oplog application on the mongod on port %d",
+                secondary.port)
+            raise errors.ServerFailure(
+                "Unable to re-enable oplog application on the mongod on port {}: {}".format(
+                    secondary.port, err.args[0]))
diff --git a/buildscripts/resmokelib/testing/testcases/json_schema_test.py b/buildscripts/resmokelib/testing/testcases/json_schema_test.py
index 802dbb792a5..51a8daa03de 100644
--- a/buildscripts/resmokelib/testing/testcases/json_schema_test.py
+++ b/buildscripts/resmokelib/testing/testcases/json_schema_test.py
@@ -9,6 +9,7 @@ from ... import config
 from ... import core
 from ... import utils
 
+
 class JSONSchemaTestCase(interface.TestCase):
     """
     A JSON Schema test to execute.
@@ -35,9 +36,6 @@ class JSONSchemaTestCase(interface.TestCase):
     def configure(self, fixture, *args, **kwargs):
         interface.TestCase.configure(self, fixture, *args, **kwargs)
 
-        if self.fixture.port is not None:
-            self.shell_options["port"] = self.fixture.port
-
         global_vars = self.shell_options.get("global_vars", {}).copy()
 
         test_data = global_vars.get("TestData", {}).copy()
@@ -58,7 +56,9 @@ class JSONSchemaTestCase(interface.TestCase):
             raise
 
     def _make_process(self):
-        return core.programs.mongo_shell_program(self.logger,
-                                                 executable=self.shell_executable,
-                                                 filename=JSONSchemaTestCase.TEST_RUNNER_FILE,
-                                                 **self.shell_options)
\ No newline at end of file
+        return core.programs.mongo_shell_program(
+            self.logger,
+            executable=self.shell_executable,
+            connection_string=self.fixture.get_driver_connection_url(),
+            filename=JSONSchemaTestCase.TEST_RUNNER_FILE,
+            **self.shell_options)
diff --git a/buildscripts/resmokelib/testing/testcases/jstest.py b/buildscripts/resmokelib/testing/testcases/jstest.py
index a38c3859228..c1c93925936 100644
--- a/buildscripts/resmokelib/testing/testcases/jstest.py
+++ b/buildscripts/resmokelib/testing/testcases/jstest.py
@@ -62,9 +62,6 @@ class JSTestCase(interface.TestCase):
     def configure(self, fixture, num_clients=DEFAULT_CLIENT_NUM, *args, **kwargs):
         interface.TestCase.configure(self, fixture, *args, **kwargs)
 
-        if self.fixture.port is not None:
-            self.shell_options["port"] = self.fixture.port
-
         global_vars = self.shell_options.get("global_vars", {}).copy()
         data_dir = self._get_data_dir(global_vars)
 
@@ -179,10 +176,12 @@ class JSTestCase(interface.TestCase):
         # set to self.logger.
         logger = utils.default_if_none(logger, self.logger)
 
-        return core.programs.mongo_shell_program(logger,
-                                                 executable=self.shell_executable,
-                                                 filename=self.js_filename,
-                                                 **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(),
+            **shell_options)
 
     def _run_test_in_thread(self, thread_id):
         # Make a logger for each thread. When this method gets called self.logger has been
diff --git a/buildscripts/resmokelib/utils/__init__.py b/buildscripts/resmokelib/utils/__init__.py
index df387cc3323..77cc6952fb0 100644
--- a/buildscripts/resmokelib/utils/__init__.py
+++ b/buildscripts/resmokelib/utils/__init__.py
@@ -6,7 +6,6 @@ from __future__ import absolute_import
 
 import os.path
 
-import pymongo
 import yaml
 
 
@@ -69,20 +68,3 @@ def load_yaml(value):
         return yaml.safe_load(value)
     except yaml.YAMLError as err:
         raise ValueError("Attempted to parse invalid YAML value '%s': %s" % (value, err))
-
-
-def new_mongo_client(port, read_preference=pymongo.ReadPreference.PRIMARY, timeout_millis=30000):
-    """
-    Returns a pymongo.MongoClient connected on 'port' with a read
-    preference of 'read_preference'.
-
-    The PyMongo driver will wait up to 'timeout_millis' milliseconds
-    before concluding that the server is unavailable.
-    """
-
-    kwargs = {"connectTimeoutMS": timeout_millis}
-    if pymongo.version_tuple[0] >= 3:
-        kwargs["serverSelectionTimeoutMS"] = timeout_millis
-        kwargs["connect"] = True
-
-    return pymongo.MongoClient(port=port, read_preference=read_preference, **kwargs)
diff --git a/jstests/hooks/run_check_repl_dbhash.js b/jstests/hooks/run_check_repl_dbhash.js
index 479abf5cf25..1afea4a8539 100644
--- a/jstests/hooks/run_check_repl_dbhash.js
+++ b/jstests/hooks/run_check_repl_dbhash.js
@@ -9,14 +9,8 @@
     // fixture. Please do not use it with other master/slave clusters.
     var MasterSlaveDBHashTest = function(primaryHost) {
         var master = new Mongo(primaryHost);
-        var resolvedHost = getHostName();
         var masterPort = master.host.split(':')[1];
-        // The 'host' property is modified manually because 'localhost' is used by default in a new
-        // Mongo() connection. We set the value to the real hostname because that is what the server
-        // uses.
-        master.host = resolvedHost + ':' + masterPort;
-
-        var slave = new Mongo(resolvedHost + ':' + String(parseInt(masterPort) + 1));
+        var slave = new Mongo('localhost:' + String(parseInt(masterPort) + 1));
 
         this.nodeList = function() {
             return [master.host, slave.host];