SERVER-19390 Make config server read commands do read committed

28 files changed, 572 insertions, 79 deletions

diff --git a/buildscripts/resmokelib/core/programs.py b/buildscripts/resmokelib/core/programs.py
index cce38bcd054..929157dbf9e 100644
--- a/buildscripts/resmokelib/core/programs.py
+++ b/buildscripts/resmokelib/core/programs.py
@@ -58,6 +58,11 @@ def mongod_program(logger, executable=None, process_kwargs=None, **kwargs):
             else:
                 kwargs[opt_name] = shortcut_opts[opt_name]
 
+    # Override the storage engine specified on the command line with "wiredTiger" if running a
+    # config server replica set.
+    if "replSet" in kwargs and "configsvr" in kwargs:
+        kwargs["storageEngine"] = "wiredTiger"
+
     # Apply the rest of the command line arguments.
     _apply_kwargs(args, kwargs)
 
diff --git a/buildscripts/resmokelib/testing/fixtures/shardedcluster.py b/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
index 5224b67cb6f..c70eb81b596 100644
--- a/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
+++ b/buildscripts/resmokelib/testing/fixtures/shardedcluster.py
@@ -4,6 +4,7 @@ Sharded cluster fixture for executing JSTests against.
 
 from __future__ import absolute_import
 
+import copy
 import os.path
 import time
 
@@ -171,10 +172,11 @@ class ShardedClusterFixture(interface.Fixture):
         logger_name = "%s:configsvr" % (self.logger.name)
         mongod_logger = logging.loggers.new_logger(logger_name, parent=self.logger)
 
-        mongod_options = self.mongod_options.copy()
+        mongod_options = copy.deepcopy(self.mongod_options)
         mongod_options["configsvr"] = ""
         mongod_options["dbpath"] = os.path.join(self._dbpath_prefix, "config")
         mongod_options["replSet"] = ShardedClusterFixture._CONFIGSVR_REPLSET_NAME
+        mongod_options["set_parameters"]["enableReplSnapshotThread"] = 1
 
         return replicaset.ReplicaSetFixture(mongod_logger,
                                             self.job_num,
@@ -193,7 +195,7 @@ class ShardedClusterFixture(interface.Fixture):
         logger_name = "%s:shard%d" % (self.logger.name, index)
         mongod_logger = logging.loggers.new_logger(logger_name, parent=self.logger)
 
-        mongod_options = self.mongod_options.copy()
+        mongod_options = copy.deepcopy(self.mongod_options)
         mongod_options["dbpath"] = os.path.join(self._dbpath_prefix, "shard%d" % (index))
 
         return standalone.MongoDFixture(mongod_logger,
@@ -211,7 +213,7 @@ class ShardedClusterFixture(interface.Fixture):
         logger_name = "%s:mongos" % (self.logger.name)
         mongos_logger = logging.loggers.new_logger(logger_name, parent=self.logger)
 
-        mongos_options = self.mongos_options.copy()
+        mongos_options = copy.deepcopy(self.mongos_options)
         if self.separate_configsvr:
             configdb_replset = ShardedClusterFixture._CONFIGSVR_REPLSET_NAME
             configdb_port = self.configsvr.port
diff --git a/src/mongo/db/auth/authz_manager_external_state_s.cpp b/src/mongo/db/auth/authz_manager_external_state_s.cpp
index bb62e56168c..b71cf0cf08c 100644
--- a/src/mongo/db/auth/authz_manager_external_state_s.cpp
+++ b/src/mongo/db/auth/authz_manager_external_state_s.cpp
@@ -69,7 +69,8 @@ Status AuthzManagerExternalStateMongos::getStoredAuthorizationVersion(OperationC
     // that runs this command
     BSONObj getParameterCmd = BSON("getParameter" << 1 << authSchemaVersionServerParameter << 1);
     BSONObjBuilder builder;
-    const bool ok = grid.catalogManager()->runReadCommand("admin", getParameterCmd, &builder);
+    const bool ok =
+        grid.catalogManager()->runUserManagementReadCommand("admin", getParameterCmd, &builder);
     BSONObj cmdResult = builder.obj();
     if (!ok) {
         return Command::getStatusFromCommandResult(cmdResult);
@@ -94,7 +95,8 @@ Status AuthzManagerExternalStateMongos::getUserDescription(OperationContext* txn
                                             << userName.getDB())) << "showPrivileges" << true
                          << "showCredentials" << true);
     BSONObjBuilder builder;
-    const bool ok = grid.catalogManager()->runReadCommand("admin", usersInfoCmd, &builder);
+    const bool ok =
+        grid.catalogManager()->runUserManagementReadCommand("admin", usersInfoCmd, &builder);
     BSONObj cmdResult = builder.obj();
     if (!ok) {
         return Command::getStatusFromCommandResult(cmdResult);
@@ -123,7 +125,8 @@ Status AuthzManagerExternalStateMongos::getRoleDescription(const RoleName& roleN
                                 << roleName.getRole() << AuthorizationManager::ROLE_DB_FIELD_NAME
                                 << roleName.getDB())) << "showPrivileges" << showPrivileges);
     BSONObjBuilder builder;
-    const bool ok = grid.catalogManager()->runReadCommand("admin", rolesInfoCmd, &builder);
+    const bool ok =
+        grid.catalogManager()->runUserManagementReadCommand("admin", rolesInfoCmd, &builder);
     BSONObj cmdResult = builder.obj();
     if (!ok) {
         return Command::getStatusFromCommandResult(cmdResult);
@@ -150,7 +153,8 @@ Status AuthzManagerExternalStateMongos::getRoleDescriptionsForDB(const std::stri
     BSONObj rolesInfoCmd = BSON("rolesInfo" << 1 << "showPrivileges" << showPrivileges
                                             << "showBuiltinRoles" << showBuiltinRoles);
     BSONObjBuilder builder;
-    const bool ok = grid.catalogManager()->runReadCommand(dbname, rolesInfoCmd, &builder);
+    const bool ok =
+        grid.catalogManager()->runUserManagementReadCommand(dbname, rolesInfoCmd, &builder);
     BSONObj cmdResult = builder.obj();
     if (!ok) {
         return Command::getStatusFromCommandResult(cmdResult);
@@ -164,7 +168,8 @@ Status AuthzManagerExternalStateMongos::getRoleDescriptionsForDB(const std::stri
 bool AuthzManagerExternalStateMongos::hasAnyPrivilegeDocuments(OperationContext* txn) {
     BSONObj usersInfoCmd = BSON("usersInfo" << 1);
     BSONObjBuilder builder;
-    const bool ok = grid.catalogManager()->runReadCommand("admin", usersInfoCmd, &builder);
+    const bool ok =
+        grid.catalogManager()->runUserManagementReadCommand("admin", usersInfoCmd, &builder);
     if (!ok) {
         // If we were unable to complete the query,
         // it's best to assume that there _are_ privilege documents.  This might happen
diff --git a/src/mongo/db/auth/user_cache_invalidator_job.cpp b/src/mongo/db/auth/user_cache_invalidator_job.cpp
index 2e44a9ff65a..dd44b200f60 100644
--- a/src/mongo/db/auth/user_cache_invalidator_job.cpp
+++ b/src/mongo/db/auth/user_cache_invalidator_job.cpp
@@ -91,7 +91,7 @@ public:
 StatusWith<OID> getCurrentCacheGeneration() {
     try {
         BSONObjBuilder result;
-        const bool ok = grid.catalogManager()->runReadCommand(
+        const bool ok = grid.catalogManager()->runUserManagementReadCommand(
             "admin", BSON("_getUserCacheGeneration" << 1), &result);
         if (!ok) {
             return Command::getStatusFromCommandResult(result.obj());
diff --git a/src/mongo/executor/network_test_env.cpp b/src/mongo/executor/network_test_env.cpp
index c65d1adcf2a..64241e72c12 100644
--- a/src/mongo/executor/network_test_env.cpp
+++ b/src/mongo/executor/network_test_env.cpp
@@ -64,6 +64,17 @@ void NetworkTestEnv::onCommand(OnCommandFunction func) {
     _mockNetwork->exitNetwork();
 }
 
+void NetworkTestEnv::onCommandWithMetadata(OnCommandWithMetadataFunction func) {
+    _mockNetwork->enterNetwork();
+
+    const NetworkInterfaceMock::NetworkOperationIterator noi = _mockNetwork->getNextReadyRequest();
+    const RemoteCommandRequest& request = noi->getRequest();
+    _mockNetwork->scheduleResponse(noi, _mockNetwork->now(), func(request));
+    _mockNetwork->runReadyNetworkOperations();
+
+    _mockNetwork->exitNetwork();
+}
+
 void NetworkTestEnv::onFindCommand(OnFindCommandFunction func) {
     onCommand([&func](const RemoteCommandRequest& request) -> StatusWith<BSONObj> {
         const auto& resultStatus = func(request);
diff --git a/src/mongo/executor/network_test_env.h b/src/mongo/executor/network_test_env.h
index b68b15a5a7f..6ef0f242597 100644
--- a/src/mongo/executor/network_test_env.h
+++ b/src/mongo/executor/network_test_env.h
@@ -129,8 +129,9 @@ public:
             std::move(future), _executor, _mockNetwork};
     }
 
-
     using OnCommandFunction = stdx::function<StatusWith<BSONObj>(const RemoteCommandRequest&)>;
+    using OnCommandWithMetadataFunction =
+        stdx::function<StatusWith<RemoteCommandResponse>(const RemoteCommandRequest&)>;
 
     using OnFindCommandFunction =
         stdx::function<StatusWith<std::vector<BSONObj>>(const RemoteCommandRequest&)>;
@@ -146,6 +147,7 @@ public:
      * single request + response or find tests.
      */
     void onCommand(OnCommandFunction func);
+    void onCommandWithMetadata(OnCommandWithMetadataFunction func);
     void onFindCommand(OnFindCommandFunction func);
 
 private:
diff --git a/src/mongo/s/catalog/catalog_manager.h b/src/mongo/s/catalog/catalog_manager.h
index 2f3ee76fcbf..366e6c63644 100644
--- a/src/mongo/s/catalog/catalog_manager.h
+++ b/src/mongo/s/catalog/catalog_manager.h
@@ -274,13 +274,20 @@ public:
                                                BSONObjBuilder* result) = 0;
 
     /**
-     * Runs a read-only command on a single config server.
+     * Runs a read-only command on a config server.
      */
     virtual bool runReadCommand(const std::string& dbname,
                                 const BSONObj& cmdObj,
                                 BSONObjBuilder* result) = 0;
 
     /**
+     * Runs a user management related read-only command on a config server.
+     */
+    virtual bool runUserManagementReadCommand(const std::string& dbname,
+                                              const BSONObj& cmdObj,
+                                              BSONObjBuilder* result) = 0;
+
+    /**
      * Applies oplog entries to the config servers.
      * Used by mergeChunk, splitChunk, and moveChunk commands.
      *
diff --git a/src/mongo/s/catalog/catalog_manager_mock.cpp b/src/mongo/s/catalog/catalog_manager_mock.cpp
index 7e4275409f1..ab2cf24bfc9 100644
--- a/src/mongo/s/catalog/catalog_manager_mock.cpp
+++ b/src/mongo/s/catalog/catalog_manager_mock.cpp
@@ -133,12 +133,18 @@ bool CatalogManagerMock::runUserManagementWriteCommand(const string& commandName
     return true;
 }
 
-bool CatalogManagerMock::runReadCommand(const string& dbname,
+bool CatalogManagerMock::runReadCommand(const std::string& dbname,
                                         const BSONObj& cmdObj,
                                         BSONObjBuilder* result) {
     return true;
 }
 
+bool CatalogManagerMock::runUserManagementReadCommand(const string& dbname,
+                                                      const BSONObj& cmdObj,
+                                                      BSONObjBuilder* result) {
+    return true;
+}
+
 Status CatalogManagerMock::applyChunkOpsDeprecated(const BSONArray& updateOps,
                                                    const BSONArray& preCondition) {
     return Status::OK();
diff --git a/src/mongo/s/catalog/catalog_manager_mock.h b/src/mongo/s/catalog/catalog_manager_mock.h
index 90e25993fcb..83bcab351e2 100644
--- a/src/mongo/s/catalog/catalog_manager_mock.h
+++ b/src/mongo/s/catalog/catalog_manager_mock.h
@@ -94,9 +94,13 @@ public:
                                        const BSONObj& cmdObj,
                                        BSONObjBuilder* result) override;
 
-    bool runReadCommand(const std::string& dbname,
-                        const BSONObj& cmdObj,
-                        BSONObjBuilder* result) override;
+    virtual bool runReadCommand(const std::string& dbname,
+                                const BSONObj& cmdObj,
+                                BSONObjBuilder* result) override;
+
+    bool runUserManagementReadCommand(const std::string& dbname,
+                                      const BSONObj& cmdObj,
+                                      BSONObjBuilder* result) override;
 
     Status applyChunkOpsDeprecated(const BSONArray& updateOps,
                                    const BSONArray& preCondition) override;
diff --git a/src/mongo/s/catalog/legacy/catalog_manager_legacy.cpp b/src/mongo/s/catalog/legacy/catalog_manager_legacy.cpp
index 4996af0c543..24b710ec14b 100644
--- a/src/mongo/s/catalog/legacy/catalog_manager_legacy.cpp
+++ b/src/mongo/s/catalog/legacy/catalog_manager_legacy.cpp
@@ -879,7 +879,13 @@ bool CatalogManagerLegacy::runUserManagementWriteCommand(const string& commandNa
     return Command::appendCommandStatus(*result, status);
 }
 
-bool CatalogManagerLegacy::runReadCommand(const string& dbname,
+bool CatalogManagerLegacy::runUserManagementReadCommand(const string& dbname,
+                                                        const BSONObj& cmdObj,
+                                                        BSONObjBuilder* result) {
+    return runReadCommand(dbname, cmdObj, result);
+}
+
+bool CatalogManagerLegacy::runReadCommand(const std::string& dbname,
                                           const BSONObj& cmdObj,
                                           BSONObjBuilder* result) {
     try {
diff --git a/src/mongo/s/catalog/legacy/catalog_manager_legacy.h b/src/mongo/s/catalog/legacy/catalog_manager_legacy.h
index 7e202d8aa2c..068b8555d91 100644
--- a/src/mongo/s/catalog/legacy/catalog_manager_legacy.h
+++ b/src/mongo/s/catalog/legacy/catalog_manager_legacy.h
@@ -101,6 +101,10 @@ public:
                         const BSONObj& cmdObj,
                         BSONObjBuilder* result) override;
 
+    bool runUserManagementReadCommand(const std::string& dbname,
+                                      const BSONObj& cmdObj,
+                                      BSONObjBuilder* result) override;
+
     Status applyChunkOpsDeprecated(const BSONArray& updateOps,
                                    const BSONArray& preCondition) override;
 
diff --git a/src/mongo/s/catalog/replset/SConscript b/src/mongo/s/catalog/replset/SConscript
index 2e7d7d72f4a..2cae356706a 100644
--- a/src/mongo/s/catalog/replset/SConscript
+++ b/src/mongo/s/catalog/replset/SConscript
@@ -35,6 +35,7 @@ env.Library(
         'catalog_manager_replica_set.cpp',
     ],
     LIBDEPS=[
+        '$BUILD_DIR/mongo/db/repl/read_concern_args',
         '$BUILD_DIR/mongo/s/catalog/catalog_manager',
         '$BUILD_DIR/mongo/s/catalog/dist_lock_manager',
         '$BUILD_DIR/mongo/s/client/sharding_client',
@@ -58,6 +59,7 @@ env.CppUnitTest(
         'catalog_manager_replica_set',
         '$BUILD_DIR/mongo/client/remote_command_targeter_mock',
         '$BUILD_DIR/mongo/db/auth/authorization_manager_mock_init',
+        '$BUILD_DIR/mongo/rpc/metadata',
         '$BUILD_DIR/mongo/executor/network_test_env',
         '$BUILD_DIR/mongo/executor/thread_pool_task_executor_test_fixture',
         '$BUILD_DIR/mongo/s/catalog/dist_lock_manager_mock',
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set.cpp
index 6296253463a..1590821c415 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set.cpp
@@ -45,8 +45,10 @@
 #include "mongo/db/commands.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/operation_context.h"
+#include "mongo/db/repl/read_concern_args.h"
 #include "mongo/executor/network_interface.h"
 #include "mongo/rpc/get_status_from_command_result.h"
+#include "mongo/rpc/metadata.h"
 #include "mongo/s/catalog/config_server_version.h"
 #include "mongo/s/catalog/dist_lock_manager.h"
 #include "mongo/s/catalog/type_actionlog.h"
@@ -86,8 +88,11 @@ namespace {
 
 // Until read committed is supported always write to the primary with majority write and read
 // from the secondary. That way we ensure that reads will see a consistent data.
-const ReadPreferenceSetting kConfigReadSelector(ReadPreference::SecondaryPreferred, TagSet{});
-
+// TODO: switch back to SecondaryPreferred once SERVER-19675 is fixed
+const ReadPreferenceSetting kConfigReadSelector(ReadPreference::PrimaryOnly, TagSet{});
+const ReadPreferenceSetting kConfigPrimaryPreferredSelector(ReadPreference::PrimaryPreferred,
+                                                            TagSet{});
+const BSONObj kReplMetadata(BSON(rpc::kReplicationMetadataFieldName << 1));
 const int kInitialSSVRetries = 3;
 const int kActionLogCollectionSize = 1024 * 1024 * 2;
 const int kChangeLogCollectionSize = 1024 * 1024 * 10;
@@ -169,7 +174,7 @@ Status CatalogManagerReplicaSet::shardCollection(OperationContext* txn,
             return readHost.getStatus();
         }
 
-        auto countStatus = _runCountCommand(
+        auto countStatus = _runCountCommandOnConfig(
             readHost.getValue(), NamespaceString(ChunkType::ConfigNS), BSON(ChunkType::ns(ns)));
         if (!countStatus.isOK()) {
             return countStatus.getStatus();
@@ -247,10 +252,10 @@ StatusWith<ShardDrainingStatus> CatalogManagerReplicaSet::removeShard(OperationC
     }
 
     // Check preconditions for removing the shard
-    auto countStatus =
-        _runCountCommand(readHost.getValue(),
-                         NamespaceString(ShardType::ConfigNS),
-                         BSON(ShardType::name() << NE << name << ShardType::draining(true)));
+    auto countStatus = _runCountCommandOnConfig(
+        readHost.getValue(),
+        NamespaceString(ShardType::ConfigNS),
+        BSON(ShardType::name() << NE << name << ShardType::draining(true)));
     if (!countStatus.isOK()) {
         return countStatus.getStatus();
     }
@@ -259,9 +264,9 @@ StatusWith<ShardDrainingStatus> CatalogManagerReplicaSet::removeShard(OperationC
                       "Can't have more than one draining shard at a time");
     }
 
-    countStatus = _runCountCommand(readHost.getValue(),
-                                   NamespaceString(ShardType::ConfigNS),
-                                   BSON(ShardType::name() << NE << name));
+    countStatus = _runCountCommandOnConfig(readHost.getValue(),
+                                           NamespaceString(ShardType::ConfigNS),
+                                           BSON(ShardType::name() << NE << name));
     if (!countStatus.isOK()) {
         return countStatus.getStatus();
     }
@@ -270,9 +275,10 @@ StatusWith<ShardDrainingStatus> CatalogManagerReplicaSet::removeShard(OperationC
     }
 
     // Figure out if shard is already draining
-    countStatus = _runCountCommand(readHost.getValue(),
-                                   NamespaceString(ShardType::ConfigNS),
-                                   BSON(ShardType::name() << name << ShardType::draining(true)));
+    countStatus =
+        _runCountCommandOnConfig(readHost.getValue(),
+                                 NamespaceString(ShardType::ConfigNS),
+                                 BSON(ShardType::name() << name << ShardType::draining(true)));
     if (!countStatus.isOK()) {
         return countStatus.getStatus();
     }
@@ -300,16 +306,16 @@ StatusWith<ShardDrainingStatus> CatalogManagerReplicaSet::removeShard(OperationC
 
     // Draining has already started, now figure out how many chunks and databases are still on the
     // shard.
-    countStatus = _runCountCommand(
+    countStatus = _runCountCommandOnConfig(
         readHost.getValue(), NamespaceString(ChunkType::ConfigNS), BSON(ChunkType::shard(name)));
     if (!countStatus.isOK()) {
         return countStatus.getStatus();
     }
     const long long chunkCount = countStatus.getValue();
 
-    countStatus = _runCountCommand(readHost.getValue(),
-                                   NamespaceString(DatabaseType::ConfigNS),
-                                   BSON(DatabaseType::primary(name)));
+    countStatus = _runCountCommandOnConfig(readHost.getValue(),
+                                           NamespaceString(DatabaseType::ConfigNS),
+                                           BSON(DatabaseType::primary(name)));
     if (!countStatus.isOK()) {
         return countStatus.getStatus();
     }
@@ -452,8 +458,7 @@ void CatalogManagerReplicaSet::logAction(const ActionLogType& actionLog) {
     if (_actionLogCollectionCreated.load() == 0) {
         BSONObj createCmd = BSON("create" << ActionLogType::ConfigNS << "capped" << true << "size"
                                           << kActionLogCollectionSize);
-        auto result =
-            grid.shardRegistry()->runCommandWithNotMasterRetries("config", "config", createCmd);
+        auto result = _runCommandOnConfigWithNotMasterRetries("config", createCmd);
         if (!result.isOK()) {
             LOG(1) << "couldn't create actionlog collection: " << causedBy(result.getStatus());
             return;
@@ -481,8 +486,7 @@ void CatalogManagerReplicaSet::logChange(const string& clientAddress,
     if (_changeLogCollectionCreated.load() == 0) {
         BSONObj createCmd = BSON("create" << ChangeLogType::ConfigNS << "capped" << true << "size"
                                           << kChangeLogCollectionSize);
-        auto result =
-            grid.shardRegistry()->runCommandWithNotMasterRetries("config", "config", createCmd);
+        auto result = _runCommandOnConfigWithNotMasterRetries("config", createCmd);
         if (!result.isOK()) {
             LOG(1) << "couldn't create changelog collection: " << causedBy(result.getStatus());
             return;
@@ -735,7 +739,7 @@ bool CatalogManagerReplicaSet::runUserManagementWriteCommand(const std::string&
         return Command::appendCommandStatus(*result, scopedDistLock.getStatus());
     }
 
-    auto response = grid.shardRegistry()->runCommandWithNotMasterRetries("config", dbname, cmdObj);
+    auto response = _runCommandOnConfigWithNotMasterRetries(dbname, cmdObj);
     if (!response.isOK()) {
         return Command::appendCommandStatus(*result, response.getStatus());
     }
@@ -746,26 +750,23 @@ bool CatalogManagerReplicaSet::runUserManagementWriteCommand(const std::string&
 bool CatalogManagerReplicaSet::runReadCommand(const std::string& dbname,
                                               const BSONObj& cmdObj,
                                               BSONObjBuilder* result) {
-    auto targeter = grid.shardRegistry()->getShard("config")->getTargeter();
-    auto target = targeter->findHost(kConfigReadSelector);
-    if (!target.isOK()) {
-        return Command::appendCommandStatus(*result, target.getStatus());
-    }
+    BSONObjBuilder cmdBuilder;
+    cmdBuilder.appendElements(cmdObj);
+    _appendReadConcern(&cmdBuilder);
 
-    auto resultStatus = grid.shardRegistry()->runCommand(target.getValue(), dbname, cmdObj);
-    if (!resultStatus.isOK()) {
-        return Command::appendCommandStatus(*result, resultStatus.getStatus());
-    }
-
-    result->appendElements(resultStatus.getValue());
+    return _runReadCommand(dbname, cmdBuilder.done(), kConfigReadSelector, result);
+}
 
-    return Command::getStatusFromCommandResult(resultStatus.getValue()).isOK();
+bool CatalogManagerReplicaSet::runUserManagementReadCommand(const std::string& dbname,
+                                                            const BSONObj& cmdObj,
+                                                            BSONObjBuilder* result) {
+    return _runReadCommand(dbname, cmdObj, kConfigPrimaryPreferredSelector, result);
 }
 
 Status CatalogManagerReplicaSet::applyChunkOpsDeprecated(const BSONArray& updateOps,
                                                          const BSONArray& preCondition) {
     BSONObj cmd = BSON("applyOps" << updateOps << "preCondition" << preCondition);
-    auto response = grid.shardRegistry()->runCommandWithNotMasterRetries("config", "config", cmd);
+    auto response = _runCommandOnConfigWithNotMasterRetries("config", cmd);
 
     if (!response.isOK()) {
         return response.getStatus();
@@ -792,7 +793,7 @@ void CatalogManagerReplicaSet::writeConfigServerDirect(const BatchedCommandReque
     invariant(dbname == "config" || dbname == "admin");
     const BSONObj cmdObj = batchRequest.toBSON();
 
-    auto response = grid.shardRegistry()->runCommandWithNotMasterRetries("config", dbname, cmdObj);
+    auto response = _runCommandOnConfigWithNotMasterRetries(dbname, cmdObj);
     if (!response.isOK()) {
         _toBatchError(response.getStatus(), batchResponse);
         return;
@@ -896,11 +897,16 @@ StatusWith<std::string> CatalogManagerReplicaSet::_generateNewShardName() const
     return Status(ErrorCodes::OperationFailed, "unable to generate new shard name");
 }
 
-StatusWith<long long> CatalogManagerReplicaSet::_runCountCommand(const HostAndPort& target,
-                                                                 const NamespaceString& ns,
-                                                                 BSONObj query) {
-    BSONObj countCmd = BSON("count" << ns.coll() << "query" << query);
-    auto responseStatus = grid.shardRegistry()->runCommand(target, ns.db().toString(), countCmd);
+StatusWith<long long> CatalogManagerReplicaSet::_runCountCommandOnConfig(const HostAndPort& target,
+                                                                         const NamespaceString& ns,
+                                                                         BSONObj query) {
+    BSONObjBuilder countBuilder;
+    countBuilder.append("count", ns.coll());
+    countBuilder.append("query", query);
+    _appendReadConcern(&countBuilder);
+
+    auto responseStatus = _runCommandOnConfig(target, ns.db().toString(), countBuilder.done());
+
     if (!responseStatus.isOK()) {
         return responseStatus.getStatus();
     }
@@ -995,8 +1001,7 @@ StatusWith<VersionType> CatalogManagerReplicaSet::_getConfigVersion() {
     }
 
     if (queryResults.empty()) {
-        auto cmdStatus =
-            grid.shardRegistry()->runCommand(readHost, "admin", BSON("listDatabases" << 1));
+        auto cmdStatus = _runCommandOnConfig(readHost, "admin", BSON("listDatabases" << 1));
         if (!cmdStatus.isOK()) {
             return cmdStatus.getStatus();
         }
@@ -1036,4 +1041,76 @@ StatusWith<VersionType> CatalogManagerReplicaSet::_getConfigVersion() {
     return versionTypeResult.getValue();
 }
 
+StatusWith<BSONObj> CatalogManagerReplicaSet::_runCommandOnConfig(const HostAndPort& target,
+                                                                  const string& dbName,
+                                                                  BSONObj cmdObj) {
+    auto result =
+        grid.shardRegistry()->runCommandWithMetadata(target, dbName, cmdObj, kReplMetadata);
+
+    if (!result.isOK()) {
+        return result.getStatus();
+    }
+
+    const auto& response = result.getValue();
+
+    _updateLastSeenConfigOpTime(response.opTime);
+
+    return response.response;
+}
+
+StatusWith<BSONObj> CatalogManagerReplicaSet::_runCommandOnConfigWithNotMasterRetries(
+    const std::string& dbName, BSONObj cmdObj) {
+    auto result = grid.shardRegistry()->runCommandWithNotMasterRetries(
+        "config", dbName, cmdObj, kReplMetadata);
+
+    if (!result.isOK()) {
+        return result.getStatus();
+    }
+
+    const auto& response = result.getValue();
+
+    _updateLastSeenConfigOpTime(response.opTime);
+
+    return response.response;
+}
+
+repl::OpTime CatalogManagerReplicaSet::_getConfigOpTime() {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    return _configOpTime;
+}
+
+void CatalogManagerReplicaSet::_updateLastSeenConfigOpTime(const repl::OpTime& optime) {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+
+    if (_configOpTime < optime) {
+        _configOpTime = optime;
+    }
+}
+
+void CatalogManagerReplicaSet::_appendReadConcern(BSONObjBuilder* builder) {
+    repl::ReadConcernArgs readConcern(_getConfigOpTime(),
+                                      repl::ReadConcernLevel::kMajorityReadConcern);
+    readConcern.appendInfo(builder);
+}
+
+bool CatalogManagerReplicaSet::_runReadCommand(const std::string& dbname,
+                                               const BSONObj& cmdObj,
+                                               const ReadPreferenceSetting& settings,
+                                               BSONObjBuilder* result) {
+    auto targeter = grid.shardRegistry()->getShard("config")->getTargeter();
+    auto target = targeter->findHost(settings);
+    if (!target.isOK()) {
+        return Command::appendCommandStatus(*result, target.getStatus());
+    }
+
+    auto resultStatus = _runCommandOnConfig(target.getValue(), dbname, cmdObj);
+    if (!resultStatus.isOK()) {
+        return Command::appendCommandStatus(*result, resultStatus.getStatus());
+    }
+
+    result->appendElements(resultStatus.getValue());
+
+    return Command::getStatusFromCommandResult(resultStatus.getValue()).isOK();
+}
+
 }  // namespace mongo
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set.h b/src/mongo/s/catalog/replset/catalog_manager_replica_set.h
index ef9abf9e734..18c2bec94b1 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set.h
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set.h
@@ -29,6 +29,7 @@
 #pragma once
 
 #include "mongo/client/connection_string.h"
+#include "mongo/db/repl/optime.h"
 #include "mongo/platform/atomic_word.h"
 #include "mongo/s/catalog/catalog_manager.h"
 #include "mongo/stdx/mutex.h"
@@ -36,6 +37,7 @@
 namespace mongo {
 
 class NamespaceString;
+struct ReadPreferenceSetting;
 class VersionType;
 
 /**
@@ -102,6 +104,10 @@ public:
                         const BSONObj& cmdObj,
                         BSONObjBuilder* result) override;
 
+    bool runUserManagementReadCommand(const std::string& dbname,
+                                      const BSONObj& cmdObj,
+                                      BSONObjBuilder* result) override;
+
     Status applyChunkOpsDeprecated(const BSONArray& updateOps,
                                    const BSONArray& preCondition) override;
 
@@ -126,36 +132,74 @@ private:
 
     StatusWith<std::string> _generateNewShardName() const override;
 
+    bool _runReadCommand(const std::string& dbname,
+                         const BSONObj& cmdObj,
+                         const ReadPreferenceSetting& settings,
+                         BSONObjBuilder* result);
+
     /**
      * Helper method for running a count command against a given target server with appropriate
      * error handling.
      */
-    StatusWith<long long> _runCountCommand(const HostAndPort& target,
-                                           const NamespaceString& ns,
-                                           BSONObj query);
+    StatusWith<long long> _runCountCommandOnConfig(const HostAndPort& target,
+                                                   const NamespaceString& ns,
+                                                   BSONObj query);
+
+    StatusWith<BSONObj> _runCommandOnConfig(const HostAndPort& target,
+                                            const std::string& dbName,
+                                            BSONObj cmdObj);
+
+    StatusWith<BSONObj> _runCommandOnConfigWithNotMasterRetries(const std::string& dbName,
+                                                                BSONObj cmdObj);
+
+    /**
+     * Appends a read committed read concern to the request object.
+     */
+    void _appendReadConcern(BSONObjBuilder* builder);
 
     /**
      * Returns the current cluster schema/protocol version.
      */
     StatusWith<VersionType> _getConfigVersion();
 
+    /**
+     * Returns the highest last known config server opTime.
+     */
+    repl::OpTime _getConfigOpTime();
+
+    /**
+     * Updates the last known config server opTime if the given opTime is newer.
+     */
+    void _updateLastSeenConfigOpTime(const repl::OpTime& optime);
+
+    //
+    // All member variables are labeled with one of the following codes indicating the
+    // synchronization rules for accessing them.
+    //
+    // (F) Self synchronizing.
+    // (M) Must hold _mutex for access.
+    // (R) Read only, can only be written during initialization.
+    //
+
+    stdx::mutex _mutex;
+
     // Config server connection string
-    ConnectionString _configServerConnectionString;
+    ConnectionString _configServerConnectionString;  // (R)
 
     // Distribted lock manager singleton.
-    std::unique_ptr<DistLockManager> _distLockManager;
+    std::unique_ptr<DistLockManager> _distLockManager;  // (R)
 
     // Whether the logAction call should attempt to create the actionlog collection
-    AtomicInt32 _actionLogCollectionCreated;
+    AtomicInt32 _actionLogCollectionCreated;  // (F)
 
     // Whether the logChange call should attempt to create the changelog collection
-    AtomicInt32 _changeLogCollectionCreated;
-
-    // protects _inShutdown
-    stdx::mutex _mutex;
+    AtomicInt32 _changeLogCollectionCreated;  // (F)
 
     // True if shutDown() has been called. False, otherwise.
-    bool _inShutdown = false;
+    bool _inShutdown = false;  // (M)
+
+    // Last known highest opTime from the config server.
+    repl::OpTime _configOpTime;  // (M)
 };
 
 }  // namespace mongo
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set_add_shard_test.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set_add_shard_test.cpp
index 0dbbeaab975..14c5b87da11 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set_add_shard_test.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set_add_shard_test.cpp
@@ -78,6 +78,8 @@ protected:
             ASSERT_EQ(request.dbname, "admin");
             ASSERT_EQ(request.cmdObj, BSON("isdbgrid" << 1));
 
+            ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
             BSONObjBuilder responseBuilder;
             Command::appendCommandStatus(
                 responseBuilder, Status(ErrorCodes::CommandNotFound, "isdbgrid command not found"));
@@ -90,6 +92,8 @@ protected:
             ASSERT_EQ(request.dbname, "admin");
             ASSERT_EQ(request.cmdObj, BSON("isMaster" << 1));
 
+            ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
             return BSON("ismaster" << true);
         });
 
@@ -98,6 +102,8 @@ protected:
             ASSERT_EQ(request.dbname, "admin");
             ASSERT_EQ(request.cmdObj, BSON("replSetGetStatus" << 1));
 
+            ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
             BSONObjBuilder responseBuilder;
             Command::appendCommandStatus(
                 responseBuilder,
@@ -116,6 +122,8 @@ protected:
             const NamespaceString nss(request.dbname, request.cmdObj.firstElement().String());
             ASSERT_EQ(nss.ns(), DatabaseType::ConfigNS);
 
+            ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
             BatchedUpdateRequest actualBatchedUpdate;
             std::string errmsg;
             ASSERT_TRUE(actualBatchedUpdate.parseBSON(request.dbname, request.cmdObj, &errmsg));
@@ -185,6 +193,8 @@ TEST_F(AddShardTest, AddShardStandalone) {
             ASSERT_EQ(request.dbname, "admin");
             ASSERT_EQ(request.cmdObj, BSON("listDatabases" << 1));
 
+            ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
             BSONArrayBuilder arr;
 
             arr.append(BSON("name"
@@ -290,6 +300,8 @@ TEST_F(AddShardTest, AddShardStandaloneGenerateName) {
             ASSERT_EQ(request.dbname, "admin");
             ASSERT_EQ(request.cmdObj, BSON("listDatabases" << 1));
 
+            ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
             BSONArrayBuilder arr;
 
             arr.append(BSON("name"
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set_drop_coll_test.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set_drop_coll_test.cpp
index 0a053edde55..d168b62edd0 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set_drop_coll_test.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set_drop_coll_test.cpp
@@ -92,15 +92,20 @@ public:
             ASSERT_EQ(_dropNS.db(), request.dbname);
             ASSERT_EQ(BSON("drop" << _dropNS.coll()), request.cmdObj);
 
+            ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
             return BSON("ns" << _dropNS.ns() << "ok" << 1);
         });
     }
 
     void expectRemoveChunksAndMarkCollectionDropped() {
         onCommand([this](const RemoteCommandRequest& request) {
+            ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
             ASSERT_EQ(_configHost, request.target);
             ASSERT_EQ("config", request.dbname);
 
+            ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
             BSONObj expectedCmd(fromjson(R"({
                 delete: "chunks",
                 deletes: [{ q: { ns: "test.user" }, limit: 0 }],
@@ -132,6 +137,8 @@ public:
             ASSERT_EQ("admin", request.dbname);
             ASSERT_EQ(BSON("unsetSharding" << 1), request.cmdObj);
 
+            ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
             return BSON("n" << 1 << "ok" << 1);
         });
     }
@@ -219,6 +226,8 @@ TEST_F(DropColl2ShardTest, NSNotFound) {
         ASSERT_EQ(dropNS().db(), request.dbname);
         ASSERT_EQ(BSON("drop" << dropNS().coll()), request.cmdObj);
 
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
         return BSON("ok" << 0 << "code" << ErrorCodes::NamespaceNotFound);
     });
 
@@ -227,6 +236,8 @@ TEST_F(DropColl2ShardTest, NSNotFound) {
         ASSERT_EQ(dropNS().db(), request.dbname);
         ASSERT_EQ(BSON("drop" << dropNS().coll()), request.cmdObj);
 
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
         return BSON("ok" << 0 << "code" << ErrorCodes::NamespaceNotFound);
     });
 
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set_log_action_test.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set_log_action_test.cpp
index f0cf6218fa8..cbb0ded71d6 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set_log_action_test.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set_log_action_test.cpp
@@ -60,6 +60,9 @@ public:
     void expectActionLogCreate(const BSONObj& response) {
         onCommand([&response](const RemoteCommandRequest& request) {
             ASSERT_EQUALS("config", request.dbname);
+
+            ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
             BSONObj expectedCreateCmd = BSON("create" << ActionLogType::ConfigNS << "capped" << true
                                                       << "size" << 1024 * 1024 * 2);
             ASSERT_EQUALS(expectedCreateCmd, request.cmdObj);
@@ -72,6 +75,8 @@ public:
         onCommand([&expectedActionLog](const RemoteCommandRequest& request) {
             ASSERT_EQUALS("config", request.dbname);
 
+            ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
             BatchedInsertRequest actualBatchedInsert;
             std::string errmsg;
             ASSERT_TRUE(actualBatchedInsert.parseBSON(request.dbname, request.cmdObj, &errmsg));
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set_remove_shard_test.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set_remove_shard_test.cpp
index 970fadff866..dc12eeb5a7d 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set_remove_shard_test.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set_remove_shard_test.cpp
@@ -146,6 +146,8 @@ TEST_F(RemoveShardTest, RemoveShardStartDraining) {
         ASSERT_EQUALS(configHost, request.target);
         ASSERT_EQUALS("config", request.dbname);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BatchedUpdateRequest actualBatchedUpdate;
         std::string errmsg;
         ASSERT_TRUE(actualBatchedUpdate.parseBSON(request.dbname, request.cmdObj, &errmsg));
@@ -318,6 +320,8 @@ TEST_F(RemoveShardTest, RemoveShardCompletion) {
         ASSERT_EQUALS(configHost, request.target);
         ASSERT_EQUALS("config", request.dbname);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BatchedDeleteRequest actualBatchedDelete;
         std::string errmsg;
         ASSERT_TRUE(actualBatchedDelete.parseBSON(request.dbname, request.cmdObj, &errmsg));
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set_shard_collection_test.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set_shard_collection_test.cpp
index 6fc42a28dd8..3c0a59a68ec 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set_shard_collection_test.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set_shard_collection_test.cpp
@@ -105,6 +105,8 @@ public:
             ASSERT_EQUALS(configHost, request.target);
             ASSERT_EQUALS("config", request.dbname);
 
+            ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
             BatchedUpdateRequest actualBatchedUpdate;
             std::string errmsg;
             ASSERT_TRUE(actualBatchedUpdate.parseBSON(request.dbname, request.cmdObj, &errmsg));
@@ -173,6 +175,8 @@ public:
             ASSERT_EQUALS(configHost, request.target);
             ASSERT_EQUALS("config", request.dbname);
 
+            ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
             BatchedUpdateRequest actualBatchedUpdate;
             std::string errmsg;
             ASSERT_TRUE(actualBatchedUpdate.parseBSON(request.dbname, request.cmdObj, &errmsg));
@@ -729,6 +733,8 @@ TEST_F(ShardCollectionTest, withInitialData) {
         ASSERT_EQUALS(0, request.cmdObj["maxSplitPoints"].numberLong());
         ASSERT_EQUALS(0, request.cmdObj["maxChunkObjects"].numberLong());
 
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
         return BSON("ok" << 1 << "splitKeys"
                          << BSON_ARRAY(splitPoint0 << splitPoint1 << splitPoint2 << splitPoint3));
     });
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set_test.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set_test.cpp
index e08996461f5..8d295a29e6c 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set_test.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set_test.cpp
@@ -38,6 +38,7 @@
 #include "mongo/db/query/lite_parsed_query.h"
 #include "mongo/executor/network_interface_mock.h"
 #include "mongo/executor/task_executor.h"
+#include "mongo/rpc/metadata/repl_set_metadata.h"
 #include "mongo/s/catalog/dist_lock_manager_mock.h"
 #include "mongo/s/catalog/replset/catalog_manager_replica_set.h"
 #include "mongo/s/catalog/replset/catalog_manager_replica_set_test_fixture.h"
@@ -64,6 +65,7 @@ using executor::NetworkInterfaceMock;
 using executor::RemoteCommandRequest;
 using executor::RemoteCommandResponse;
 using executor::TaskExecutor;
+using rpc::ReplSetMetadata;
 using std::string;
 using std::vector;
 using stdx::chrono::milliseconds;
@@ -482,8 +484,8 @@ TEST_F(CatalogManagerReplSetTest, RunUserManagementReadCommand) {
 
     auto future = launchAsync([this] {
         BSONObjBuilder responseBuilder;
-        bool ok =
-            catalogManager()->runReadCommand("test", BSON("usersInfo" << 1), &responseBuilder);
+        bool ok = catalogManager()->runUserManagementReadCommand(
+            "test", BSON("usersInfo" << 1), &responseBuilder);
         ASSERT_TRUE(ok);
 
         BSONObj response = responseBuilder.obj();
@@ -493,6 +495,8 @@ TEST_F(CatalogManagerReplSetTest, RunUserManagementReadCommand) {
     });
 
     onCommand([](const RemoteCommandRequest& request) {
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         ASSERT_EQUALS("test", request.dbname);
         ASSERT_EQUALS(BSON("usersInfo" << 1), request.cmdObj);
 
@@ -508,7 +512,8 @@ TEST_F(CatalogManagerReplSetTest, RunUserManagementReadCommandUnsatisfiedReadPre
         Status(ErrorCodes::FailedToSatisfyReadPreference, "no nodes up"));
 
     BSONObjBuilder responseBuilder;
-    bool ok = catalogManager()->runReadCommand("test", BSON("usersInfo" << 1), &responseBuilder);
+    bool ok = catalogManager()->runUserManagementReadCommand(
+        "test", BSON("usersInfo" << 1), &responseBuilder);
     ASSERT_FALSE(ok);
 
     Status commandStatus = Command::getStatusFromCommandResult(responseBuilder.obj());
@@ -571,6 +576,8 @@ TEST_F(CatalogManagerReplSetTest, RunUserManagementWriteCommandSuccess) {
                            << "test"),
                       request.cmdObj);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BSONObjBuilder responseBuilder;
         Command::appendCommandStatus(responseBuilder,
                                      Status(ErrorCodes::UserNotFound, "User test@test not found"));
@@ -669,6 +676,8 @@ TEST_F(CatalogManagerReplSetTest, RunUserManagementWriteCommandNotMasterRetrySuc
                            << "test"),
                       request.cmdObj);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         return BSON("ok" << 1);
     });
 
@@ -1212,6 +1221,8 @@ TEST_F(CatalogManagerReplSetTest, UpdateDatabase) {
     onCommand([dbt](const RemoteCommandRequest& request) {
         ASSERT_EQUALS("config", request.dbname);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BatchedUpdateRequest actualBatchedUpdate;
         std::string errmsg;
         ASSERT_TRUE(actualBatchedUpdate.parseBSON(request.dbname, request.cmdObj, &errmsg));
@@ -1284,6 +1295,9 @@ TEST_F(CatalogManagerReplSetTest, ApplyChunkOpsDeprecated) {
 
     onCommand([updateOps, preCondition](const RemoteCommandRequest& request) {
         ASSERT_EQUALS("config", request.dbname);
+
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         ASSERT_EQUALS(updateOps, request.cmdObj["applyOps"].Obj());
         ASSERT_EQUALS(preCondition, request.cmdObj["preCondition"].Obj());
 
@@ -1316,6 +1330,8 @@ TEST_F(CatalogManagerReplSetTest, ApplyChunkOpsDeprecatedCommandFailed) {
         ASSERT_EQUALS(updateOps, request.cmdObj["applyOps"].Obj());
         ASSERT_EQUALS(preCondition, request.cmdObj["preCondition"].Obj());
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BSONObjBuilder responseBuilder;
         Command::appendCommandStatus(responseBuilder,
                                      Status(ErrorCodes::BadValue, "precondition failed"));
@@ -1399,6 +1415,8 @@ TEST_F(CatalogManagerReplSetTest, createDatabaseSuccess) {
         string cmdName = request.cmdObj.firstElement().fieldName();
         ASSERT_EQUALS("listDatabases", cmdName);
 
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
         return BSON("ok" << 1 << "totalSize" << 10);
     });
 
@@ -1409,6 +1427,8 @@ TEST_F(CatalogManagerReplSetTest, createDatabaseSuccess) {
         string cmdName = request.cmdObj.firstElement().fieldName();
         ASSERT_EQUALS("listDatabases", cmdName);
 
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
         return BSON("ok" << 1 << "totalSize" << 1);
     });
 
@@ -1419,6 +1439,8 @@ TEST_F(CatalogManagerReplSetTest, createDatabaseSuccess) {
         string cmdName = request.cmdObj.firstElement().fieldName();
         ASSERT_EQUALS("listDatabases", cmdName);
 
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
         return BSON("ok" << 1 << "totalSize" << 100);
     });
 
@@ -1427,6 +1449,8 @@ TEST_F(CatalogManagerReplSetTest, createDatabaseSuccess) {
         ASSERT_EQUALS(configHost, request.target);
         ASSERT_EQUALS("config", request.dbname);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BatchedInsertRequest actualBatchedInsert;
         std::string errmsg;
         ASSERT_TRUE(actualBatchedInsert.parseBSON(request.dbname, request.cmdObj, &errmsg));
@@ -1657,6 +1681,8 @@ TEST_F(CatalogManagerReplSetTest, createDatabaseDuplicateKeyOnInsert) {
         string cmdName = request.cmdObj.firstElement().fieldName();
         ASSERT_EQUALS("listDatabases", cmdName);
 
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
         return BSON("ok" << 1 << "totalSize" << 10);
     });
 
@@ -1667,6 +1693,8 @@ TEST_F(CatalogManagerReplSetTest, createDatabaseDuplicateKeyOnInsert) {
         string cmdName = request.cmdObj.firstElement().fieldName();
         ASSERT_EQUALS("listDatabases", cmdName);
 
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
         return BSON("ok" << 1 << "totalSize" << 1);
     });
 
@@ -1677,6 +1705,8 @@ TEST_F(CatalogManagerReplSetTest, createDatabaseDuplicateKeyOnInsert) {
         string cmdName = request.cmdObj.firstElement().fieldName();
         ASSERT_EQUALS("listDatabases", cmdName);
 
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
         return BSON("ok" << 1 << "totalSize" << 100);
     });
 
@@ -1685,6 +1715,8 @@ TEST_F(CatalogManagerReplSetTest, createDatabaseDuplicateKeyOnInsert) {
         ASSERT_EQUALS(configHost, request.target);
         ASSERT_EQUALS("config", request.dbname);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BatchedInsertRequest actualBatchedInsert;
         std::string errmsg;
         ASSERT_TRUE(actualBatchedInsert.parseBSON(request.dbname, request.cmdObj, &errmsg));
@@ -1765,6 +1797,8 @@ TEST_F(CatalogManagerReplSetTest, EnableShardingNoDBExists) {
         ASSERT_EQ("admin", request.dbname);
         ASSERT_EQ(BSON("listDatabases" << 1), request.cmdObj);
 
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
+
         return fromjson(R"({
                 databases: [],
                 totalSize: 1,
@@ -1776,6 +1810,8 @@ TEST_F(CatalogManagerReplSetTest, EnableShardingNoDBExists) {
         ASSERT_EQ(HostAndPort("config:123"), request.target);
         ASSERT_EQ("config", request.dbname);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BSONObj expectedCmd(fromjson(R"({
             update: "databases",
             updates: [{
@@ -1871,6 +1907,8 @@ TEST_F(CatalogManagerReplSetTest, EnableShardingDBExists) {
         ASSERT_EQ(HostAndPort("config:123"), request.target);
         ASSERT_EQ("config", request.dbname);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BSONObj expectedCmd(fromjson(R"({
             update: "databases",
             updates: [{
@@ -1948,5 +1986,128 @@ TEST_F(CatalogManagerReplSetTest, EnableShardingNoDBExistsNoShards) {
     future.timed_get(kFutureTimeout);
 }
 
+TEST_F(CatalogManagerReplSetTest, BasicReadAfterOpTime) {
+    configTargeter()->setFindHostReturnValue(HostAndPort("TestHost1"));
+
+    repl::OpTime lastOpTime;
+    for (int x = 0; x < 3; x++) {
+        auto future = launchAsync([this] {
+            BSONObjBuilder responseBuilder;
+            ASSERT_TRUE(
+                catalogManager()->runReadCommand("test", BSON("dummy" << 1), &responseBuilder));
+        });
+
+        const repl::OpTime newOpTime(Timestamp(x + 2, x + 6), x + 5);
+
+        onCommandWithMetadata([this, &newOpTime, &lastOpTime](const RemoteCommandRequest& request) {
+            ASSERT_EQUALS("test", request.dbname);
+
+            ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
+            ASSERT_EQ(string("dummy"), request.cmdObj.firstElementFieldName());
+            checkReadConcern(request.cmdObj, lastOpTime.getTimestamp(), lastOpTime.getTerm());
+
+            ReplSetMetadata metadata(12, newOpTime, 100, 3);
+            BSONObjBuilder builder;
+            BSONObjBuilder replBuilder(builder.subobjStart(rpc::kReplicationMetadataFieldName));
+            metadata.writeToMetadata(&replBuilder);
+            replBuilder.done();
+
+            return RemoteCommandResponse(BSON("ok" << 1), builder.obj(), Milliseconds(1));
+        });
+
+        // Now wait for the runReadCommand call to return
+        future.timed_get(kFutureTimeout);
+
+        lastOpTime = newOpTime;
+    }
+}
+
+TEST_F(CatalogManagerReplSetTest, ReadAfterOpTimeShouldNotGoBack) {
+    configTargeter()->setFindHostReturnValue(HostAndPort("TestHost1"));
+
+    // Initialize the internal config OpTime
+    auto future1 = launchAsync([this] {
+        BSONObjBuilder responseBuilder;
+        ASSERT_TRUE(catalogManager()->runReadCommand("test", BSON("dummy" << 1), &responseBuilder));
+    });
+
+    repl::OpTime highestOpTime;
+    const repl::OpTime newOpTime(Timestamp(7, 6), 5);
+
+    onCommandWithMetadata([this, &newOpTime, &highestOpTime](const RemoteCommandRequest& request) {
+        ASSERT_EQUALS("test", request.dbname);
+
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
+        ASSERT_EQ(string("dummy"), request.cmdObj.firstElementFieldName());
+        checkReadConcern(request.cmdObj, highestOpTime.getTimestamp(), highestOpTime.getTerm());
+
+        ReplSetMetadata metadata(12, newOpTime, 100, 3);
+        BSONObjBuilder builder;
+        BSONObjBuilder replBuilder(builder.subobjStart(rpc::kReplicationMetadataFieldName));
+        metadata.writeToMetadata(&replBuilder);
+        replBuilder.done();
+
+        return RemoteCommandResponse(BSON("ok" << 1), builder.obj(), Milliseconds(1));
+    });
+
+    future1.timed_get(kFutureTimeout);
+
+    highestOpTime = newOpTime;
+
+    // Return an older OpTime
+    auto future2 = launchAsync([this] {
+        BSONObjBuilder responseBuilder;
+        ASSERT_TRUE(catalogManager()->runReadCommand("test", BSON("dummy" << 1), &responseBuilder));
+    });
+
+    const repl::OpTime oldOpTime(Timestamp(3, 10), 5);
+
+    onCommandWithMetadata([this, &oldOpTime, &highestOpTime](const RemoteCommandRequest& request) {
+        ASSERT_EQUALS("test", request.dbname);
+
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
+        ASSERT_EQ(string("dummy"), request.cmdObj.firstElementFieldName());
+        checkReadConcern(request.cmdObj, highestOpTime.getTimestamp(), highestOpTime.getTerm());
+
+        ReplSetMetadata metadata(12, oldOpTime, 100, 3);
+        BSONObjBuilder builder;
+        BSONObjBuilder replBuilder(builder.subobjStart(rpc::kReplicationMetadataFieldName));
+        metadata.writeToMetadata(&replBuilder);
+        replBuilder.done();
+
+        return RemoteCommandResponse(BSON("ok" << 1), builder.obj(), Milliseconds(1));
+    });
+
+    future2.timed_get(kFutureTimeout);
+
+    // Check that older OpTime does not override highest OpTime
+    auto future3 = launchAsync([this] {
+        BSONObjBuilder responseBuilder;
+        ASSERT_TRUE(catalogManager()->runReadCommand("test", BSON("dummy" << 1), &responseBuilder));
+    });
+
+    onCommandWithMetadata([this, &oldOpTime, &highestOpTime](const RemoteCommandRequest& request) {
+        ASSERT_EQUALS("test", request.dbname);
+
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
+        ASSERT_EQ(string("dummy"), request.cmdObj.firstElementFieldName());
+        checkReadConcern(request.cmdObj, highestOpTime.getTimestamp(), highestOpTime.getTerm());
+
+        ReplSetMetadata metadata(12, oldOpTime, 100, 3);
+        BSONObjBuilder builder;
+        BSONObjBuilder replBuilder(builder.subobjStart(rpc::kReplicationMetadataFieldName));
+        metadata.writeToMetadata(&replBuilder);
+        replBuilder.done();
+
+        return RemoteCommandResponse(BSON("ok" << 1), builder.obj(), Milliseconds(1));
+    });
+
+    future3.timed_get(kFutureTimeout);
+}
+
 }  // namespace
 }  // namespace mongo
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set_test_fixture.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set_test_fixture.cpp
index 767555bcc13..3b0036418a5 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set_test_fixture.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set_test_fixture.cpp
@@ -40,6 +40,7 @@
 #include "mongo/db/commands.h"
 #include "mongo/db/namespace_string.h"
 #include "mongo/db/query/lite_parsed_query.h"
+#include "mongo/db/repl/read_concern_args.h"
 #include "mongo/db/service_context_noop.h"
 #include "mongo/executor/network_interface_mock.h"
 #include "mongo/executor/thread_pool_task_executor_test_fixture.h"
@@ -179,6 +180,11 @@ void CatalogManagerReplSetTestFixture::onCommand(NetworkTestEnv::OnCommandFuncti
     _networkTestEnv->onCommand(func);
 }
 
+void CatalogManagerReplSetTestFixture::onCommandWithMetadata(
+    NetworkTestEnv::OnCommandWithMetadataFunction func) {
+    _networkTestEnv->onCommandWithMetadata(func);
+}
+
 void CatalogManagerReplSetTestFixture::onFindCommand(NetworkTestEnv::OnFindCommandFunction func) {
     _networkTestEnv->onFindCommand(func);
 }
@@ -312,6 +318,7 @@ void CatalogManagerReplSetTestFixture::expectUpdateCollection(const HostAndPort&
                                                               const CollectionType& coll) {
     onCommand([&](const RemoteCommandRequest& request) {
         ASSERT_EQUALS(expectedHost, request.target);
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
         ASSERT_EQUALS("config", request.dbname);
 
         BatchedUpdateRequest actualBatchedUpdate;
@@ -342,6 +349,7 @@ void CatalogManagerReplSetTestFixture::expectSetShardVersion(
     const ChunkVersion& expectedChunkVersion) {
     onCommand([&](const RemoteCommandRequest& request) {
         ASSERT_EQ(expectedHost, request.target);
+        ASSERT_EQUALS(rpc::makeEmptyMetadata(), request.metadata);
 
         SetShardVersionRequest ssv =
             assertGet(SetShardVersionRequest::parseFromBSON(request.cmdObj));
@@ -379,10 +387,32 @@ void CatalogManagerReplSetTestFixture::expectCount(const HostAndPort& configHost
             return BSON("ok" << 1 << "n" << response.getValue());
         }
 
+        checkReadConcern(request.cmdObj, Timestamp(0, 0), 0);
+
         BSONObjBuilder responseBuilder;
         Command::appendCommandStatus(responseBuilder, response.getStatus());
         return responseBuilder.obj();
     });
 }
 
+void CatalogManagerReplSetTestFixture::checkReadConcern(const BSONObj& cmdObj,
+                                                        const Timestamp& expectedTS,
+                                                        long long expectedTerm) const {
+    auto readConcernElem = cmdObj[repl::ReadConcernArgs::kReadConcernFieldName];
+    ASSERT_EQ(Object, readConcernElem.type());
+
+    auto readConcernObj = readConcernElem.Obj();
+    ASSERT_EQ("majority", readConcernObj[repl::ReadConcernArgs::kLevelFieldName].str());
+
+    auto afterElem = readConcernObj[repl::ReadConcernArgs::kOpTimeFieldName];
+    ASSERT_EQ(Object, afterElem.type());
+
+    auto afterObj = afterElem.Obj();
+
+    ASSERT_TRUE(afterObj.hasField(repl::ReadConcernArgs::kOpTimestampFieldName));
+    ASSERT_EQ(expectedTS, afterObj[repl::ReadConcernArgs::kOpTimestampFieldName].timestamp());
+    ASSERT_TRUE(afterObj.hasField(repl::ReadConcernArgs::kOpTermFieldName));
+    ASSERT_EQ(expectedTerm, afterObj[repl::ReadConcernArgs::kOpTermFieldName].numberLong());
+}
+
 }  // namespace mongo
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set_test_fixture.h b/src/mongo/s/catalog/replset/catalog_manager_replica_set_test_fixture.h
index 5a1fce08408..67d8d678637 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set_test_fixture.h
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set_test_fixture.h
@@ -94,6 +94,7 @@ protected:
      * single request + response or find tests.
      */
     void onCommand(executor::NetworkTestEnv::OnCommandFunction func);
+    void onCommandWithMetadata(executor::NetworkTestEnv::OnCommandWithMetadataFunction func);
     void onFindCommand(executor::NetworkTestEnv::OnFindCommandFunction func);
 
     /**
@@ -157,6 +158,13 @@ protected:
 
     void shutdownExecutor();
 
+    /**
+     * Checks that the given command has the expected settings for read after opTime.
+     */
+    void checkReadConcern(const BSONObj& cmdObj,
+                          const Timestamp& expectedTS,
+                          long long expectedTerm) const;
+
 private:
     std::unique_ptr<ServiceContext> _service;
     ServiceContext::UniqueClient _client;
diff --git a/src/mongo/s/catalog/replset/catalog_manager_replica_set_upgrade_test.cpp b/src/mongo/s/catalog/replset/catalog_manager_replica_set_upgrade_test.cpp
index 51afc7b40b3..c20e98a4ef9 100644
--- a/src/mongo/s/catalog/replset/catalog_manager_replica_set_upgrade_test.cpp
+++ b/src/mongo/s/catalog/replset/catalog_manager_replica_set_upgrade_test.cpp
@@ -151,6 +151,8 @@ TEST_F(CatalogManagerReplSetTestFixture, UpgradeNoVersionDocEmptyConfig) {
         ASSERT_EQ("admin", request.dbname);
         ASSERT_EQ(BSON("listDatabases" << 1), request.cmdObj);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         return fromjson(R"({
                     databases: [
                         { name: "local" }
@@ -164,6 +166,8 @@ TEST_F(CatalogManagerReplSetTestFixture, UpgradeNoVersionDocEmptyConfig) {
         ASSERT_EQ(HostAndPort("config:123"), request.target);
         ASSERT_EQ("config", request.dbname);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BatchedUpdateRequest actualBatchedUpdate;
         std::string errmsg;
         ASSERT_TRUE(actualBatchedUpdate.parseBSON(request.dbname, request.cmdObj, &errmsg));
@@ -210,6 +214,8 @@ TEST_F(CatalogManagerReplSetTestFixture, UpgradeNoVersionDocEmptyConfigWithAdmin
         ASSERT_EQ("admin", request.dbname);
         ASSERT_EQ(BSON("listDatabases" << 1), request.cmdObj);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         return fromjson(R"({
                     databases: [
                         { name: "local" },
@@ -224,6 +230,8 @@ TEST_F(CatalogManagerReplSetTestFixture, UpgradeNoVersionDocEmptyConfigWithAdmin
         ASSERT_EQ(HostAndPort("config:123"), request.target);
         ASSERT_EQ("config", request.dbname);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         BatchedUpdateRequest actualBatchedUpdate;
         std::string errmsg;
         ASSERT_TRUE(actualBatchedUpdate.parseBSON(request.dbname, request.cmdObj, &errmsg));
@@ -255,6 +263,8 @@ TEST_F(CatalogManagerReplSetTestFixture, UpgradeWriteError) {
         ASSERT_EQ("admin", request.dbname);
         ASSERT_EQ(BSON("listDatabases" << 1), request.cmdObj);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         return fromjson(R"({
                     databases: [
                         { name: "local" }
@@ -296,6 +306,8 @@ TEST_F(CatalogManagerReplSetTestFixture, UpgradeNoVersionDocNonEmptyConfigServer
         ASSERT_EQ("admin", request.dbname);
         ASSERT_EQ(BSON("listDatabases" << 1), request.cmdObj);
 
+        ASSERT_EQUALS(BSON(rpc::kReplicationMetadataFieldName << 1), request.metadata);
+
         return fromjson(R"({
                     databases: [
                         { name: "local" },
diff --git a/src/mongo/s/client/SConscript b/src/mongo/s/client/SConscript
index d99b3c99995..d51711e66f3 100644
--- a/src/mongo/s/client/SConscript
+++ b/src/mongo/s/client/SConscript
@@ -15,6 +15,7 @@ env.Library(
         '$BUILD_DIR/mongo/client/fetcher',
         '$BUILD_DIR/mongo/client/remote_command_runner_impl',
         '$BUILD_DIR/mongo/client/remote_command_targeter',
+        '$BUILD_DIR/mongo/rpc/metadata',
     ]
 )
 
diff --git a/src/mongo/s/client/shard_registry.cpp b/src/mongo/s/client/shard_registry.cpp
index f44b800a989..90866b677b9 100644
--- a/src/mongo/s/client/shard_registry.cpp
+++ b/src/mongo/s/client/shard_registry.cpp
@@ -39,6 +39,7 @@
 #include "mongo/client/replica_set_monitor.h"
 #include "mongo/executor/task_executor.h"
 #include "mongo/rpc/get_status_from_command_result.h"
+#include "mongo/rpc/metadata/repl_set_metadata.h"
 #include "mongo/s/catalog/catalog_manager.h"
 #include "mongo/s/catalog/type_shard.h"
 #include "mongo/s/client/shard.h"
@@ -322,10 +323,24 @@ StatusWith<std::vector<BSONObj>> ShardRegistry::exhaustiveFind(const HostAndPort
 StatusWith<BSONObj> ShardRegistry::runCommand(const HostAndPort& host,
                                               const std::string& dbName,
                                               const BSONObj& cmdObj) {
+    auto status = runCommandWithMetadata(host, dbName, cmdObj, rpc::makeEmptyMetadata());
+
+    if (!status.isOK()) {
+        return status.getStatus();
+    }
+
+    return status.getValue().response;
+}
+
+StatusWith<ShardRegistry::CommandResponse> ShardRegistry::runCommandWithMetadata(
+    const HostAndPort& host,
+    const std::string& dbName,
+    const BSONObj& cmdObj,
+    const BSONObj& metadata) {
     StatusWith<executor::RemoteCommandResponse> responseStatus =
         Status(ErrorCodes::InternalError, "Internal error running command");
 
-    executor::RemoteCommandRequest request(host, dbName, cmdObj, kConfigCommandTimeout);
+    executor::RemoteCommandRequest request(host, dbName, cmdObj, metadata, kConfigCommandTimeout);
     auto callStatus =
         _executor->scheduleRemoteCommand(request,
                                          [&responseStatus](const RemoteCommandCallbackArgs& args) {
@@ -342,12 +357,42 @@ StatusWith<BSONObj> ShardRegistry::runCommand(const HostAndPort& host,
         return responseStatus.getStatus();
     }
 
-    return responseStatus.getValue().data;
+    auto response = responseStatus.getValue();
+
+    CommandResponse cmdResponse;
+    cmdResponse.response = response.data;
+
+    if (auto replField = response.metadata[rpc::kReplicationMetadataFieldName]) {
+        auto replParseStatus = rpc::ReplSetMetadata::readFromMetadata(replField.Obj());
+
+        if (!replParseStatus.isOK()) {
+            return replParseStatus.getStatus();
+        }
+
+        // TODO: SERVER-19734 use config server snapshot time.
+        cmdResponse.opTime = replParseStatus.getValue().getLastCommittedOptime();
+    }
+
+    return cmdResponse;
 }
 
 StatusWith<BSONObj> ShardRegistry::runCommandWithNotMasterRetries(const ShardId& shardId,
                                                                   const std::string& dbname,
                                                                   const BSONObj& cmdObj) {
+    auto status = runCommandWithNotMasterRetries(shardId, dbname, cmdObj, rpc::makeEmptyMetadata());
+
+    if (!status.isOK()) {
+        return status.getStatus();
+    }
+
+    return status.getValue().response;
+}
+
+StatusWith<ShardRegistry::CommandResponse> ShardRegistry::runCommandWithNotMasterRetries(
+    const ShardId& shardId,
+    const std::string& dbname,
+    const BSONObj& cmdObj,
+    const BSONObj& metadata) {
     auto targeter = getShard(shardId)->getTargeter();
     const ReadPreferenceSetting readPref(ReadPreference::PrimaryOnly, TagSet{});
 
@@ -365,12 +410,12 @@ StatusWith<BSONObj> ShardRegistry::runCommandWithNotMasterRetries(const ShardId&
             return target.getStatus();
         }
 
-        auto response = runCommand(target.getValue(), dbname, cmdObj);
+        auto response = runCommandWithMetadata(target.getValue(), dbname, cmdObj, metadata);
         if (!response.isOK()) {
             return response.getStatus();
         }
 
-        Status commandStatus = getStatusFromCommandResult(response.getValue());
+        Status commandStatus = getStatusFromCommandResult(response.getValue().response);
         if (ErrorCodes::NotMaster == commandStatus ||
             ErrorCodes::NotMasterNoSlaveOkCode == commandStatus) {
             targeter->markHostNotMaster(target.getValue());
diff --git a/src/mongo/s/client/shard_registry.h b/src/mongo/s/client/shard_registry.h
index 6f5fc76ea4c..634bcdf2340 100644
--- a/src/mongo/s/client/shard_registry.h
+++ b/src/mongo/s/client/shard_registry.h
@@ -34,6 +34,8 @@
 #include <vector>
 
 #include "mongo/base/disallow_copying.h"
+#include "mongo/db/jsobj.h"
+#include "mongo/db/repl/optime.h"
 #include "mongo/s/client/shard.h"
 #include "mongo/stdx/mutex.h"
 
@@ -65,6 +67,11 @@ class ShardRegistry {
     MONGO_DISALLOW_COPYING(ShardRegistry);
 
 public:
+    struct CommandResponse {
+        BSONObj response;
+        repl::OpTime opTime;
+    };
+
     /**
      * Instantiates a new shard registry.
      *
@@ -153,6 +160,14 @@ public:
      * Runs a command against the specified host and returns the result.  It is the responsibility
      * of the caller to check the returned BSON for command-specific failures.
      */
+    StatusWith<CommandResponse> runCommandWithMetadata(const HostAndPort& host,
+                                                       const std::string& dbName,
+                                                       const BSONObj& cmdObj,
+                                                       const BSONObj& metadata);
+
+    /**
+     * Runs a command against the specified host and returns the result.
+     */
     StatusWith<BSONObj> runCommand(const HostAndPort& host,
                                    const std::string& dbName,
                                    const BSONObj& cmdObj);
@@ -172,6 +187,11 @@ public:
                                                        const std::string& dbname,
                                                        const BSONObj& cmdObj);
 
+    StatusWith<CommandResponse> runCommandWithNotMasterRetries(const ShardId& shardId,
+                                                               const std::string& dbname,
+                                                               const BSONObj& cmdObj,
+                                                               const BSONObj& metadata);
+
 private:
     typedef std::map<ShardId, std::shared_ptr<Shard>> ShardMap;
 
diff --git a/src/mongo/s/commands/cluster_user_management_commands.cpp b/src/mongo/s/commands/cluster_user_management_commands.cpp
index 0bb67e31c2a..d2a6ab667d4 100644
--- a/src/mongo/s/commands/cluster_user_management_commands.cpp
+++ b/src/mongo/s/commands/cluster_user_management_commands.cpp
@@ -352,7 +352,7 @@ public:
              int options,
              string& errmsg,
              BSONObjBuilder& result) {
-        return grid.catalogManager()->runReadCommand(dbname, cmdObj, &result);
+        return grid.catalogManager()->runUserManagementReadCommand(dbname, cmdObj, &result);
     }
 
 } cmdUsersInfo;
@@ -710,7 +710,7 @@ public:
              int options,
              string& errmsg,
              BSONObjBuilder& result) {
-        return grid.catalogManager()->runReadCommand(dbname, cmdObj, &result);
+        return grid.catalogManager()->runUserManagementReadCommand(dbname, cmdObj, &result);
     }
 
 } cmdRolesInfo;
diff --git a/src/mongo/shell/servers.js b/src/mongo/shell/servers.js
index baf0c58a270..90ad37bb223 100755
--- a/src/mongo/shell/servers.js
+++ b/src/mongo/shell/servers.js
@@ -828,6 +828,9 @@ function appendSetParameterArgs(argArray) {
                     });
                 }
             }
+            if (argArray.indexOf('--configsvr') > 0 && argArray.indexOf('--replSet') > 0) {
+                argArray.push.apply(argArray, ['--setParameter', "enableReplSnapshotThread=1"]);
+            }
         }
     }
     return argArray;