SERVER-23698 Removed ability to run replSetInitiate if not started as a replica set node

11 files changed, 63 insertions, 460 deletions

diff --git a/jstests/replsets/initiate_without_replset_name_at_startup.js b/jstests/replsets/initiate_without_replset_name_at_startup.js
deleted file mode 100644
index a21467768e0..00000000000
--- a/jstests/replsets/initiate_without_replset_name_at_startup.js
+++ /dev/null
@@ -1,180 +0,0 @@
-/**
- * If a node is started with --configsvr but without --replSet, and it has neither an oplog nor a
- * local replica set  config document, the operator should be able to run replSetInitiate to create
- * a single-node replica set configuration and to prime the oplog. Then, on restart if the operator
- * adds --replSet to the startup configuration directives, the node can immediately transition into
- * PRIMARY rather than waiting in STARTUP for the operator to run replSetInitiate. This should
- * only be allowed for single-node replica set configurations.
- *
- * This test cannot be run on ephemeral storage engines, since their replica set config document
- * will not persist across a restart and they will not transition to PRIMARY as described above.
- * @tags: [requires_persistence]
- */
-(function() {
-    "use strict";
-
-    var baseName = 'testInitiateWithoutReplSetNameAtStartup';
-    var port = allocatePorts(1)[0];
-    var dbpath = MongoRunner.dataPath + baseName + '/';
-
-    var mongod = MongoRunner.runMongod({dbpath: dbpath, port: port});
-
-    var config = {
-        _id: baseName,
-        version: 1,
-        members: [{_id: 0, host: mongod.name}, ],
-    };
-
-    var result = assert.commandFailedWithCode(
-        mongod.getDB('admin').runCommand({replSetInitiate: config}),
-        ErrorCodes.NoReplicationEnabled,
-        'replSetInitiate should fail when both --configsvr and --replSet are missing.');
-    assert(result.errmsg.match(/This node was not started with the replSet option/),
-           'unexpected error message when both --configsvr and --replSet are missing. ' +
-               'configuration: ' + tojson(result));
-
-    // The rest of this test can only be run if the storageEngine supports committed reads.
-    var supportsCommittedReads =
-        mongod.getDB('admin').serverStatus().storageEngine.supportsCommittedReads;
-
-    MongoRunner.stopMongod(port);
-
-    if (!supportsCommittedReads) {
-        jsTestLog('Skipping rest of test because storage engine does not support committed reads');
-        return;
-    }
-
-    mongod = MongoRunner.runMongod({configsvr: '', dbpath: dbpath, port: port, restart: true});
-
-    assert.commandWorked(mongod.getDB('admin').runCommand({replSetInitiate: config}),
-                         'replSetInitiate should not fail when given a valid configuration');
-
-    // Check saved config
-    var systemReplsetCollection = mongod.getDB('local').system.replset;
-    assert.eq(
-        1,
-        systemReplsetCollection.count(),
-        'replSetInitiate did not save configuration in ' + systemReplsetCollection.getFullName());
-    var savedConfig = systemReplsetCollection.findOne();
-    assert.eq(config._id,
-              savedConfig._id,
-              'config passed to replSetInitiate (left side) does not match config saved in ' +
-                  systemReplsetCollection.getFullName() + ' (right side)');
-
-    result = assert.commandFailedWithCode(
-        mongod.getDB('admin').runCommand({
-            replSetInitiate: {
-                _id: baseName + '-2',
-                version: 1,
-                members: [{_id: 0, host: mongod.name}, ],
-            }
-        }),
-        ErrorCodes.AlreadyInitialized,
-        'expected AlreadyInitialized error code when configuration already exists in ' +
-            systemReplsetCollection.getFullName());
-    assert(
-        result.errmsg.match(/already initialized/),
-        'unexpected error message when replica set configuration already exists ' + tojson(result));
-    systemReplsetCollection = mongod.getDB('local').system.replset;
-    savedConfig = systemReplsetCollection.findOne();
-    assert.eq(config._id,
-              savedConfig._id,
-              'config passed to replSetInitiate (left side) does not match config saved in ' +
-                  systemReplsetCollection.getFullName() + ' (right side)');
-
-    var oplogCollection = mongod.getDB('local').oplog.rs;
-    assert(oplogCollection.exists(),
-           'oplog collection ' + oplogCollection.getFullName() +
-               ' not created after successful replSetInitiate. Collections in local database: ' +
-               mongod.getDB('local').getCollectionNames().join(', '));
-    assert(oplogCollection.isCapped(),
-           'oplog collection ' + oplogCollection.getFullName() + ' must be capped');
-    assert.eq(1,
-              oplogCollection.count(),
-              'oplog collection ' + oplogCollection.getFullName() +
-                  ' is not initialized with first entry.');
-    var oplogEntry = oplogCollection.findOne();
-    assert.eq('n', oplogEntry.op, 'unexpected first oplog entry type: ' + tojson(oplogEntry));
-
-    MongoRunner.stopMongod(port);
-
-    // Restart server and attempt to save a different config.
-    mongod = MongoRunner.runMongod({configsvr: '', dbpath: dbpath, port: port, restart: true});
-    result = assert.commandFailedWithCode(
-        mongod.getDB('admin').runCommand({
-            replSetInitiate: {
-                _id: baseName + '-2',
-                version: 1,
-                members: [{_id: 0, host: mongod.name}, ],
-            }
-        }),
-        ErrorCodes.AlreadyInitialized,
-        'expected AlreadyInitialized error code when configuration already exists in ' +
-            systemReplsetCollection.getFullName() + ' after restarting');
-    assert(result.errmsg.match(/already initialized/),
-           'unexpected error message when replica set configuration already exists ' +
-               '(after restarting without --replSet): ' + tojson(result));
-    systemReplsetCollection = mongod.getDB('local').system.replset;
-    savedConfig = systemReplsetCollection.findOne();
-    assert.eq(config._id,
-              savedConfig._id,
-              'config passed to replSetInitiate (left side) does not match config saved in ' +
-                  systemReplsetCollection.getFullName() + ' (right side)');
-
-    MongoRunner.stopMongod(port);
-
-    // Restart server with --replSet and check own replica member state.
-    mongod = MongoRunner.runMongod(
-        {configsvr: '', dbpath: dbpath, port: port, replSet: config._id, restart: true});
-
-    // Wait for member state to become PRIMARY.
-    assert.soon(
-        function() {
-            result = mongod.getDB('admin').runCommand({replSetGetStatus: 1});
-            if (result.ok !== 1) {
-                // Command might fail if we are still loading the config for replset.
-                return false;
-            }
-            assert.eq(
-                1, result.members.length, 'replica set status should contain exactly 1 member');
-            var member = result.members[0];
-            print('Current replica member state = ' + member.state + ' (' + member.stateStr + ')');
-            return member.state == ReplSetTest.State.PRIMARY;
-        },
-        'Replica set member state did not reach PRIMARY after starting up with --replSet option',
-        5000,
-        1000);
-
-    // Write/read a single document to ensure basic functionality.
-    var t = mongod.getDB('config').getCollection(baseName);
-    var doc = {
-        _id: 0
-    };
-    assert.soon(function() {
-        result = t.save(doc);
-        assert(result instanceof WriteResult);
-        if (result.hasWriteError()) {
-            print('Failed with write error saving document after transitioning to primary: ' +
-                  tojson(result) + '. Retrying...');
-            return false;
-        }
-        if (result.hasWriteConcernError()) {
-            print('Failed with write concern error saving document after transitioning to ' +
-                  'primary: ' + tojson(result) + '. Retrying...');
-            return false;
-        }
-        print('Successfully saved document after transitioning to primary: ' + tojson(result));
-        return true;
-    }, 'failed to save document after transitioning to primary', 5000, 1000);
-
-    assert.eq(1, t.count(), 'incorrect collection size after successful write');
-    assert.eq(doc, t.findOne());
-
-    oplogCollection = mongod.getDB('local').oplog.rs;
-    oplogEntry = oplogCollection.find().sort({$natural: -1}).limit(1).next();
-    assert.eq('i', oplogEntry.op, 'unexpected optype for insert oplog entry');
-    assert.eq(t.getFullName(), oplogEntry.ns, 'unexpected namespace for insert oplog entry');
-    assert.eq(doc, oplogEntry.o, 'unexpected embedded object for insert oplog entry');
-
-    MongoRunner.stopMongod(port);
-}());
diff --git a/src/mongo/db/repl/oplog.cpp b/src/mongo/db/repl/oplog.cpp
index b59d8b2a75e..0d66d00aad6 100644
--- a/src/mongo/db/repl/oplog.cpp
+++ b/src/mongo/db/repl/oplog.cpp
@@ -363,7 +363,6 @@ void _logOpsInner(OperationContext* txn,
                   size_t nWriters,
                   Collection* oplogCollection,
                   ReplicationCoordinator::Mode replicationMode,
-                  bool updateReplOpTime,
                   OpTime finalOpTime) {
     ReplicationCoordinator* replCoord = getGlobalReplicationCoordinator();
 
@@ -378,36 +377,32 @@ void _logOpsInner(OperationContext* txn,
     checkOplogInsert(oplogCollection->insertDocumentsForOplog(txn, writers, nWriters));
 
     // Set replCoord last optime only after we're sure the WUOW didn't abort and roll back.
-    if (updateReplOpTime) {
-        txn->recoveryUnit()->onCommit(
-            [replCoord, finalOpTime] { replCoord->setMyLastAppliedOpTimeForward(finalOpTime); });
-    }
+    txn->recoveryUnit()->onCommit(
+        [replCoord, finalOpTime] { replCoord->setMyLastAppliedOpTimeForward(finalOpTime); });
 
     ReplClientInfo::forClient(txn->getClient()).setLastOp(finalOpTime);
 }
 
-void _logOp(OperationContext* txn,
-            const char* opstr,
-            const char* ns,
-            const BSONObj& obj,
-            const BSONObj* o2,
-            bool fromMigrate,
-            const std::string& oplogName,
-            ReplicationCoordinator::Mode replMode,
-            bool updateOpTime) {
+void logOp(OperationContext* txn,
+           const char* opstr,
+           const char* ns,
+           const BSONObj& obj,
+           const BSONObj* o2,
+           bool fromMigrate) {
+    ReplicationCoordinator::Mode replMode = ReplicationCoordinator::get(txn)->getReplicationMode();
     NamespaceString nss(ns);
     if (oplogDisabled(txn, replMode, nss))
         return;
 
     ReplicationCoordinator* replCoord = getGlobalReplicationCoordinator();
-    Collection* oplog = getLocalOplogCollection(txn, oplogName);
+    Collection* oplog = getLocalOplogCollection(txn, _oplogCollectionName);
     Lock::DBLock lk(txn->lockState(), "local", MODE_IX);
-    Lock::CollectionLock lock(txn->lockState(), oplogName, MODE_IX);
+    Lock::CollectionLock lock(txn->lockState(), _oplogCollectionName, MODE_IX);
     OplogSlot slot;
     getNextOpTime(txn, oplog, replCoord, replMode, 1, &slot);
     auto writer = _logOpWriter(txn, opstr, nss, obj, o2, fromMigrate, slot.opTime, slot.hash);
     const DocWriter* basePtr = &writer;
-    _logOpsInner(txn, nss, &basePtr, 1, oplog, replMode, updateOpTime, slot.opTime);
+    _logOpsInner(txn, nss, &basePtr, 1, oplog, replMode, slot.opTime);
 }
 
 void logOps(OperationContext* txn,
@@ -440,20 +435,10 @@ void logOps(OperationContext* txn,
     for (size_t i = 0; i < count; i++) {
         basePtrs[i] = &writers[i];
     }
-    _logOpsInner(txn, nss, basePtrs.get(), count, oplog, replMode, true, slots[count - 1].opTime);
+    _logOpsInner(txn, nss, basePtrs.get(), count, oplog, replMode, slots[count - 1].opTime);
 }
 
 
-void logOp(OperationContext* txn,
-           const char* opstr,
-           const char* ns,
-           const BSONObj& obj,
-           const BSONObj* o2,
-           bool fromMigrate) {
-    ReplicationCoordinator::Mode replMode = ReplicationCoordinator::get(txn)->getReplicationMode();
-    _logOp(txn, opstr, ns, obj, o2, fromMigrate, _oplogCollectionName, replMode, true);
-}
-
 OpTime writeOpsToOplog(OperationContext* txn, const std::vector<BSONObj>& ops) {
     OpTime lastOptime;
     MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
@@ -532,14 +517,15 @@ long long getNewOplogSizeBytes(OperationContext* txn, const ReplSettings& replSe
 }
 }  // namespace
 
-void createOplog(OperationContext* txn, const std::string& oplogCollectionName, bool replEnabled) {
+void createOplog(OperationContext* txn) {
     ScopedTransaction transaction(txn, MODE_X);
     Lock::GlobalWrite lk(txn->lockState());
 
     const ReplSettings& replSettings = ReplicationCoordinator::get(txn)->getSettings();
+    bool replEnabled = replSettings.usingReplSets();
 
-    OldClientContext ctx(txn, oplogCollectionName);
-    Collection* collection = ctx.db()->getCollection(oplogCollectionName);
+    OldClientContext ctx(txn, _oplogCollectionName);
+    Collection* collection = ctx.db()->getCollection(_oplogCollectionName);
 
     if (collection) {
         if (replSettings.getOplogSizeBytes() != 0) {
@@ -558,7 +544,7 @@ void createOplog(OperationContext* txn, const std::string& oplogCollectionName,
         }
 
         if (!replEnabled)
-            initTimestampFromOplog(txn, oplogCollectionName);
+            initTimestampFromOplog(txn, _oplogCollectionName);
         return;
     }
 
@@ -575,12 +561,12 @@ void createOplog(OperationContext* txn, const std::string& oplogCollectionName,
 
     MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
         WriteUnitOfWork uow(txn);
-        invariant(ctx.db()->createCollection(txn, oplogCollectionName, options));
+        invariant(ctx.db()->createCollection(txn, _oplogCollectionName, options));
         if (!replEnabled)
             getGlobalServiceContext()->getOpObserver()->onOpMessage(txn, BSONObj());
         uow.commit();
     }
-    MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "createCollection", oplogCollectionName);
+    MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "createCollection", _oplogCollectionName);
 
     /* sync here so we don't get any surprising lag later when we try to sync */
     StorageEngine* storageEngine = getGlobalServiceContext()->getGlobalStorageEngine();
@@ -588,12 +574,6 @@ void createOplog(OperationContext* txn, const std::string& oplogCollectionName,
     log() << "******" << endl;
 }
 
-void createOplog(OperationContext* txn) {
-    const auto replEnabled = ReplicationCoordinator::get(txn)->getReplicationMode() ==
-        ReplicationCoordinator::modeReplSet;
-    createOplog(txn, _oplogCollectionName, replEnabled);
-}
-
 // -------------------------------------
 
 namespace {
diff --git a/src/mongo/db/repl/oplog.h b/src/mongo/db/repl/oplog.h
index b8182448997..d009083c709 100644
--- a/src/mongo/db/repl/oplog.h
+++ b/src/mongo/db/repl/oplog.h
@@ -58,12 +58,6 @@ class ReplSettings;
  */
 void truncateOplogTo(OperationContext* txn, Timestamp truncateTimestamp);
 
-/**
- * Create a new capped collection for the oplog if it doesn't yet exist.
- * If the collection already exists, set the 'last' OpTime if master/slave (side effect!)
- */
-void createOplog(OperationContext* txn, const std::string& oplogCollectionName, bool replEnabled);
-
 /*
  * Create a new capped collection for the oplog using createOplog() if it doesn't yet exist.
  * Collection name will be "_oplogCollectionName" initialized in setOplogCollectionName().
@@ -102,19 +96,7 @@ void logOps(OperationContext* txn,
 
 /* For 'u' records, 'obj' captures the mutation made to the object but not
  * the object itself. 'o2' captures the the criteria for the object that will be modified.
- *
- * Sets replCoord last optime if 'updateReplOpTime' is true.
  */
-void _logOp(OperationContext* txn,
-            const char* opstr,
-            const char* ns,
-            const BSONObj& obj,
-            const BSONObj* o2,
-            bool fromMigrate,
-            const std::string& oplogCollectionName,
-            ReplicationCoordinator::Mode replicationMode,
-            bool updateReplOpTime);
-
 void logOp(OperationContext* txn,
            const char* opstr,
            const char* ns,
diff --git a/src/mongo/db/repl/replication_coordinator_external_state.h b/src/mongo/db/repl/replication_coordinator_external_state.h
index 4a58018474a..3fc7913e3b4 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state.h
@@ -104,12 +104,9 @@ public:
     virtual void shutdown() = 0;
 
     /**
-     * Creates the oplog, writes the first entry and stores the replica set config document.  Sets
-     * replCoord last optime if 'updateReplOpTime' is true.
+     * Creates the oplog, writes the first entry and stores the replica set config document.
      */
-    virtual Status initializeReplSetStorage(OperationContext* txn,
-                                            const BSONObj& config,
-                                            bool updateReplOpTime) = 0;
+    virtual Status initializeReplSetStorage(OperationContext* txn, const BSONObj& config) = 0;
 
     /**
      * Writes a message about our transition to primary to the oplog.
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
index d7e413b590e..e705fd17c9d 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
@@ -180,10 +180,9 @@ void ReplicationCoordinatorExternalStateImpl::shutdown() {
 }
 
 Status ReplicationCoordinatorExternalStateImpl::initializeReplSetStorage(OperationContext* txn,
-                                                                         const BSONObj& config,
-                                                                         bool updateReplOpTime) {
+                                                                         const BSONObj& config) {
     try {
-        createOplog(txn, rsOplogName, true);
+        createOplog(txn);
 
         MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
             ScopedTransaction scopedXact(txn, MODE_X);
@@ -193,26 +192,7 @@ Status ReplicationCoordinatorExternalStateImpl::initializeReplSetStorage(Operati
             Helpers::putSingleton(txn, configCollectionName, config);
             const auto msgObj = BSON("msg"
                                      << "initiating set");
-            if (updateReplOpTime) {
-                getGlobalServiceContext()->getOpObserver()->onOpMessage(txn, msgObj);
-            } else {
-                // 'updateReplOpTime' is false when called from the replSetInitiate command when the
-                // server is running with replication disabled. We bypass onOpMessage to invoke
-                // _logOp directly so that we can override the replication mode and keep _logO from
-                // updating the replication coordinator's op time (illegal operation when
-                // replication is not enabled).
-                repl::oplogCheckCloseDatabase(txn, nullptr);
-                repl::_logOp(txn,
-                             "n",
-                             "",
-                             msgObj,
-                             nullptr,
-                             false,
-                             rsOplogName,
-                             ReplicationCoordinator::modeReplSet,
-                             updateReplOpTime);
-                repl::oplogCheckCloseDatabase(txn, nullptr);
-            }
+            getGlobalServiceContext()->getOpObserver()->onOpMessage(txn, msgObj);
             wuow.commit();
         }
         MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn, "initiate oplog entry", "local.oplog.rs");
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_impl.h b/src/mongo/db/repl/replication_coordinator_external_state_impl.h
index a74976dbc5e..4ddac22d4a1 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.h
@@ -58,9 +58,7 @@ public:
 
     virtual void startMasterSlave(OperationContext* txn);
     virtual void shutdown();
-    virtual Status initializeReplSetStorage(OperationContext* txn,
-                                            const BSONObj& config,
-                                            bool updateReplOpTime);
+    virtual Status initializeReplSetStorage(OperationContext* txn, const BSONObj& config);
     virtual void logTransitionToPrimaryToOplog(OperationContext* txn);
     virtual void forwardSlaveProgress();
     virtual OID ensureMe(OperationContext* txn);
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp b/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
index 2d7736def87..36b4ec96d01 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
@@ -65,8 +65,7 @@ void ReplicationCoordinatorExternalStateMock::startSteadyStateReplication() {}
 
 void ReplicationCoordinatorExternalStateMock::startMasterSlave(OperationContext*) {}
 Status ReplicationCoordinatorExternalStateMock::initializeReplSetStorage(OperationContext* txn,
-                                                                         const BSONObj& config,
-                                                                         bool updateReplOpTime) {
+                                                                         const BSONObj& config) {
     return storeLocalConfigDocument(txn, config);
 }
 
diff --git a/src/mongo/db/repl/replication_coordinator_external_state_mock.h b/src/mongo/db/repl/replication_coordinator_external_state_mock.h
index 049f39745c8..898edb0d125 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_mock.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state_mock.h
@@ -58,9 +58,7 @@ public:
     virtual void startSteadyStateReplication() override;
     virtual void startMasterSlave(OperationContext*);
     virtual void shutdown();
-    virtual Status initializeReplSetStorage(OperationContext* txn,
-                                            const BSONObj& config,
-                                            bool updateReplOpTime);
+    virtual Status initializeReplSetStorage(OperationContext* txn, const BSONObj& config);
     virtual void logTransitionToPrimaryToOplog(OperationContext* txn);
     virtual void forwardSlaveProgress();
     virtual OID ensureMe(OperationContext*);
diff --git a/src/mongo/db/repl/replication_coordinator_impl.cpp b/src/mongo/db/repl/replication_coordinator_impl.cpp
index 3b5319b8cc7..172f10b8a08 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl.cpp
@@ -2314,25 +2314,21 @@ Status ReplicationCoordinatorImpl::processReplSetInitiate(OperationContext* txn,
                                                           BSONObjBuilder* resultObj) {
     log() << "replSetInitiate admin command received from client";
 
-    // Skip config state changes if server is not running with replication enabled.
     const auto replEnabled = _settings.usingReplSets();
     stdx::unique_lock<stdx::mutex> lk(_mutex);
-    if (replEnabled) {
-        while (_rsConfigState == kConfigPreStart || _rsConfigState == kConfigStartingUp) {
-            _rsConfigStateChange.wait(lk);
-        }
+    if (!replEnabled) {
+        return Status(ErrorCodes::NoReplicationEnabled, "server is not running with --replSet");
+    }
+    while (_rsConfigState == kConfigPreStart || _rsConfigState == kConfigStartingUp) {
+        _rsConfigStateChange.wait(lk);
+    }
 
-        if (_rsConfigState != kConfigUninitialized) {
-            resultObj->append("info",
-                              "try querying local.system.replset to see current configuration");
-            return Status(ErrorCodes::AlreadyInitialized, "already initialized");
-        }
-        invariant(!_rsConfig.isInitialized());
-        _setConfigState_inlock(kConfigInitiating);
-    } else if (_externalState->loadLocalConfigDocument(txn).isOK()) {
+    if (_rsConfigState != kConfigUninitialized) {
         resultObj->append("info", "try querying local.system.replset to see current configuration");
         return Status(ErrorCodes::AlreadyInitialized, "already initialized");
     }
+    invariant(!_rsConfig.isInitialized());
+    _setConfigState_inlock(kConfigInitiating);
 
     ScopeGuard configStateGuard = MakeGuard(
         lockAndCall,
@@ -2341,17 +2337,13 @@ Status ReplicationCoordinatorImpl::processReplSetInitiate(OperationContext* txn,
             &ReplicationCoordinatorImpl::_setConfigState_inlock, this, kConfigUninitialized));
     lk.unlock();
 
-    if (!replEnabled) {
-        configStateGuard.Dismiss();
-    }
-
     ReplicaSetConfig newConfig;
     Status status = newConfig.initializeForInitiate(configObj, true);
     if (!status.isOK()) {
         error() << "replSet initiate got " << status << " while parsing " << configObj;
         return Status(ErrorCodes::InvalidReplicaSetConfig, status.reason());
     }
-    if (replEnabled && newConfig.getReplSetName() != _settings.ourSetName()) {
+    if (newConfig.getReplSetName() != _settings.ourSetName()) {
         str::stream errmsg;
         errmsg << "Attempting to initiate a replica set with name " << newConfig.getReplSetName()
                << ", but command line reports " << _settings.ourSetName() << "; rejecting";
@@ -2366,51 +2358,38 @@ Status ReplicationCoordinatorImpl::processReplSetInitiate(OperationContext* txn,
         return Status(ErrorCodes::InvalidReplicaSetConfig, myIndex.getStatus().reason());
     }
 
-    if (!replEnabled && newConfig.getNumMembers() != 1) {
-        str::stream errmsg;
-        errmsg << "When replication is not enabled (no --replSet option) you can only specify one "
-               << "member in the config. " << newConfig.getNumMembers() << " members found in"
-               << "configuration: " << newConfig.toBSON();
-        error() << std::string(errmsg);
-        return Status(ErrorCodes::InvalidReplicaSetConfig, errmsg);
-    }
-
     log() << "replSetInitiate config object with " << newConfig.getNumMembers()
           << " members parses ok";
 
-    if (replEnabled) {
-        status = checkQuorumForInitiate(&_replExecutor, newConfig, myIndex.getValue());
+    status = checkQuorumForInitiate(&_replExecutor, newConfig, myIndex.getValue());
 
-        if (!status.isOK()) {
-            error() << "replSetInitiate failed; " << status;
-            return status;
-        }
+    if (!status.isOK()) {
+        error() << "replSetInitiate failed; " << status;
+        return status;
     }
 
-    status = _externalState->initializeReplSetStorage(txn, newConfig.toBSON(), replEnabled);
+    status = _externalState->initializeReplSetStorage(txn, newConfig.toBSON());
     if (!status.isOK()) {
         error() << "replSetInitiate failed to store config document or create the oplog; "
                 << status;
         return status;
     }
 
-    if (replEnabled) {
-        // Since the JournalListener has not yet been set up, we must manually set our
-        // durableOpTime.
-        setMyLastDurableOpTime(getMyLastAppliedOpTime());
-
-        {
-            LockGuard topoLock(_topoMutex);
-            _finishReplSetInitiate(newConfig, myIndex.getValue());
-        }
+    // Since the JournalListener has not yet been set up, we must manually set our
+    // durableOpTime.
+    setMyLastDurableOpTime(getMyLastAppliedOpTime());
 
-        // A configuration passed to replSetInitiate() with the current node as an arbiter
-        // will fail validation with a "replSet initiate got ... while validating" reason.
-        invariant(!newConfig.getMemberAt(myIndex.getValue()).isArbiter());
-        _externalState->startThreads(_settings);
-        _startDataReplication(txn);
+    {
+        LockGuard topoLock(_topoMutex);
+        _finishReplSetInitiate(newConfig, myIndex.getValue());
     }
 
+    // A configuration passed to replSetInitiate() with the current node as an arbiter
+    // will fail validation with a "replSet initiate got ... while validating" reason.
+    invariant(!newConfig.getMemberAt(myIndex.getValue()).isArbiter());
+    _externalState->startThreads(_settings);
+    _startDataReplication(txn);
+
     configStateGuard.Dismiss();
     return Status::OK();
 }
diff --git a/src/mongo/db/repl/replication_coordinator_impl_test.cpp b/src/mongo/db/repl/replication_coordinator_impl_test.cpp
index d86e17f72a9..41bbb2a2d4b 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_test.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_test.cpp
@@ -385,7 +385,7 @@ TEST_F(ReplCoordTest,
 
 TEST_F(ReplCoordTest, NodeReturnsInvalidReplicaSetConfigWhenInitiatingWithAnEmptyConfig) {
     OperationContextNoop txn;
-    init("");
+    init("mySet");
     start(HostAndPort("node1", 12345));
     ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
 
@@ -398,7 +398,7 @@ TEST_F(ReplCoordTest, NodeReturnsInvalidReplicaSetConfigWhenInitiatingWithAnEmpt
 
 TEST_F(ReplCoordTest, NodeReturnsInvalidReplicaSetConfigWhenInitiatingWithoutAn_idField) {
     OperationContextNoop txn;
-    init("");
+    init("mySet");
     start(HostAndPort("node1", 12345));
     ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
 
@@ -416,7 +416,7 @@ TEST_F(ReplCoordTest, NodeReturnsInvalidReplicaSetConfigWhenInitiatingWithoutAn_
 TEST_F(ReplCoordTest,
        NodeReturnsInvalidReplicaSetConfigWhenInitiatingWithAConfigVersionNotEqualToOne) {
     OperationContextNoop txn;
-    init("");
+    init("mySet");
     start(HostAndPort("node1", 12345));
     ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
 
@@ -434,140 +434,15 @@ TEST_F(ReplCoordTest,
     ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
 }
 
-TEST_F(ReplCoordTest, InitiateFailsWithoutReplSetFlagWithMoreThanOneMember) {
-    OperationContextNoop txn;
-    init("");
-    start(HostAndPort("node1", 12345));
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-
-    BSONObjBuilder result1;
-    auto status =
-        getReplCoord()->processReplSetInitiate(&txn,
-                                               BSON("_id"
-                                                    << "mySet"
-                                                    << "version" << 1 << "members"
-                                                    << BSON_ARRAY(BSON("_id" << 0 << "host"
-                                                                             << "node1:12345")
-                                                                  << BSON("_id" << 1 << "host"
-                                                                                << "node2:12345"))),
-                                               &result1);
-    ASSERT_EQUALS(ErrorCodes::InvalidReplicaSetConfig, status);
-    ASSERT_STRING_CONTAINS(status.reason(), "you can only specify one member in the config");
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-}
-
-TEST_F(ReplCoordTest, InitiateFailsWithoutReplSetFlagWithSelfMissing) {
-    OperationContextNoop txn;
-    init("");
-    start(HostAndPort("node1", 12345));
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-
-    BSONObjBuilder result1;
-    auto status =
-        getReplCoord()->processReplSetInitiate(&txn,
-                                               BSON("_id"
-                                                    << "mySet"
-                                                    << "version" << 1 << "members"
-                                                    << BSON_ARRAY(BSON("_id" << 0 << "host"
-                                                                             << "node5:12345"))),
-                                               &result1);
-    ASSERT_EQUALS(ErrorCodes::InvalidReplicaSetConfig, status);
-    ASSERT_STRING_CONTAINS(status.reason(), "No host described in new configuration");
-    ASSERT_STRING_CONTAINS(status.reason(), "maps to this node");
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-}
-
-TEST_F(ReplCoordTest, InitiateFailsWithoutReplSetFlagWithArbiterMember) {
+TEST_F(ReplCoordTest, InitiateFailsWithoutReplSetFlag) {
     OperationContextNoop txn;
     init("");
     start(HostAndPort("node1", 12345));
     ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
 
     BSONObjBuilder result1;
-    auto status = getReplCoord()->processReplSetInitiate(
-        &txn,
-        BSON("_id"
-             << "mySet"
-             << "version" << 1 << "members" << BSON_ARRAY(BSON("_id" << 0 << "host"
-                                                                     << "node1:12345"
-                                                                     << "arbiterOnly" << true))),
-        &result1);
-    ASSERT_EQUALS(ErrorCodes::InvalidReplicaSetConfig, status);
-    ASSERT_STRING_CONTAINS(status.reason(), "must contain at least one non-arbiter member");
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-}
-
-TEST_F(ReplCoordTest, InitiateFailsWithoutReplSetFlagWithPriorityZero) {
-    OperationContextNoop txn;
-    init("");
-    start(HostAndPort("node1", 12345));
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-
-    BSONObjBuilder result1;
-    auto status =
-        getReplCoord()->processReplSetInitiate(&txn,
-                                               BSON("_id"
-                                                    << "mySet"
-                                                    << "version" << 1 << "members"
-                                                    << BSON_ARRAY(BSON("_id" << 0 << "host"
-                                                                             << "node1:12345"
-                                                                             << "priority" << 0))),
-                                               &result1);
-    ASSERT_EQUALS(ErrorCodes::InvalidReplicaSetConfig, status);
-    ASSERT_STRING_CONTAINS(status.reason(), "must contain at least one non-arbiter member");
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-}
-
-TEST_F(ReplCoordTest, InitiateFailsWithoutReplSetFlagWithNoVotes) {
-    OperationContextNoop txn;
-    init("");
-    start(HostAndPort("node1", 12345));
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-
-    BSONObjBuilder result1;
-    auto status =
-        getReplCoord()->processReplSetInitiate(&txn,
-                                               BSON("_id"
-                                                    << "mySet"
-                                                    << "version" << 1 << "members"
-                                                    << BSON_ARRAY(BSON("_id" << 0 << "host"
-                                                                             << "node1:12345"
-                                                                             << "votes" << 0))),
-                                               &result1);
-    ASSERT_EQUALS(ErrorCodes::InvalidReplicaSetConfig, status);
-    ASSERT_STRING_CONTAINS(status.reason(), "priority must be 0 when non-voting (votes:0)");
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-}
-
-TEST_F(ReplCoordTest, InitiateFailsWithoutReplSetFlagWithHiddenMember) {
-    OperationContextNoop txn;
-    init("");
-    start(HostAndPort("node1", 12345));
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-
-    BSONObjBuilder result1;
-    auto status =
-        getReplCoord()->processReplSetInitiate(&txn,
-                                               BSON("_id"
-                                                    << "mySet"
-                                                    << "version" << 1 << "members"
-                                                    << BSON_ARRAY(BSON("_id" << 0 << "host"
-                                                                             << "node1:12345"
-                                                                             << "hidden" << true))),
-                                               &result1);
-    ASSERT_EQUALS(ErrorCodes::InvalidReplicaSetConfig, status);
-    ASSERT_STRING_CONTAINS(status.reason(), "priority must be 0 when hidden=true");
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-}
-
-TEST_F(ReplCoordTest, InitiatePassesWithoutReplSetFlagWithValidConfiguration) {
-    OperationContextNoop txn;
-    init("");
-    start(HostAndPort("node1", 12345));
-    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
-
-    BSONObjBuilder result1;
-    ASSERT_OK(
+    ASSERT_EQUALS(
+        ErrorCodes::NoReplicationEnabled,
         getReplCoord()->processReplSetInitiate(&txn,
                                                BSON("_id"
                                                     << "mySet"
@@ -575,6 +450,7 @@ TEST_F(ReplCoordTest, InitiatePassesWithoutReplSetFlagWithValidConfiguration) {
                                                     << BSON_ARRAY(BSON("_id" << 0 << "host"
                                                                              << "node1:12345"))),
                                                &result1));
+    ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
 }
 
 TEST_F(ReplCoordTest, NodeReturnsOutOfDiskSpaceWhenInitiateCannotWriteConfigToDisk) {
diff --git a/src/mongo/db/repl/replset_commands.cpp b/src/mongo/db/repl/replset_commands.cpp
index e12f0405751..70aaa8b7b6d 100644
--- a/src/mongo/db/repl/replset_commands.cpp
+++ b/src/mongo/db/repl/replset_commands.cpp
@@ -354,15 +354,9 @@ public:
         std::string replSetString =
             ReplicationCoordinator::get(txn)->getSettings().getReplSetString();
         if (replSetString.empty()) {
-            if (serverGlobalParams.clusterRole == ClusterRole::ConfigServer) {
-                return appendCommandStatus(result,
-                                           ReplicationCoordinator::get(txn)
-                                               ->processReplSetInitiate(txn, configObj, &result));
-            }
             return appendCommandStatus(result,
                                        Status(ErrorCodes::NoReplicationEnabled,
-                                              "This node was not started with the replSet "
-                                              "option"));
+                                              "This node was not started with the replSet option"));
         }
 
         if (configObj.isEmpty()) {