SERVER-18253 create VoteRequester Scatter-Gather Algorithm to conduct new style elections

24 files changed, 1199 insertions, 50 deletions

diff --git a/src/mongo/db/repl/SConscript b/src/mongo/db/repl/SConscript
index 1e0a12989f4..a8e96c93f40 100644
--- a/src/mongo/db/repl/SConscript
+++ b/src/mongo/db/repl/SConscript
@@ -113,6 +113,7 @@ env.Library('repl_coordinator_impl',
                 'replication_coordinator_impl.cpp',
                 'replication_coordinator_impl_elect.cpp',
                 'replication_coordinator_impl_heartbeat.cpp',
+                'vote_requester.cpp',
             ],
             LIBDEPS=[
                      '$BUILD_DIR/mongo/db/common',
@@ -186,6 +187,12 @@ env.CppUnitTest('freshness_checker_test',
                          'replica_set_messages',
                          'replmocks'])
 
+env.CppUnitTest('vote_requester_test',
+                'vote_requester_test.cpp',
+                LIBDEPS=['repl_coordinator_impl',
+                         'replica_set_messages',
+                         'replmocks'])
+
 env.CppUnitTest('election_winner_declarer_test',
                 'election_winner_declarer_test.cpp',
                 LIBDEPS=['repl_coordinator_impl',
@@ -247,9 +254,11 @@ env.Library('replica_set_messages',
                 'repl_set_heartbeat_response.cpp',
                 'repl_set_heartbeat_response_v1.cpp',
                 'repl_set_html_summary.cpp',
+                'repl_set_request_votes_args.cpp',
                 'replica_set_config.cpp',
                 'replica_set_tag.cpp',
                 'update_position_args.cpp',
+                'last_vote.cpp',
             ],
             LIBDEPS=[
                 '$BUILD_DIR/mongo/bson',
@@ -283,7 +292,6 @@ env.Library(
         'replset_commands.cpp',
         'repl_set_command.cpp',
         'repl_set_request_votes.cpp',
-        'repl_set_request_votes_args.cpp',
         'repl_set_declare_election_winner.cpp',
     ],
     LIBDEPS=[
diff --git a/src/mongo/db/repl/last_vote.cpp b/src/mongo/db/repl/last_vote.cpp
new file mode 100644
index 00000000000..e7a1b178bf4
--- /dev/null
+++ b/src/mongo/db/repl/last_vote.cpp
@@ -0,0 +1,92 @@
+/**
+ *    Copyright (C) 2015 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/db/repl/last_vote.h"
+
+#include "mongo/bson/util/bson_check.h"
+#include "mongo/bson/util/bson_extract.h"
+#include "mongo/db/jsobj.h"
+
+namespace mongo {
+namespace repl {
+namespace {
+
+    const std::string kCandidateIdFieldName = "candidateId";
+    const std::string kTermFieldName = "term";
+
+    const std::string kLegalFieldNames[] = {
+        kCandidateIdFieldName,
+        kTermFieldName,
+    };
+
+}  // namespace
+
+    Status LastVote::initialize(const BSONObj& argsObj) {
+        Status status = bsonCheckOnlyHasFields("VotedFar",
+                                               argsObj,
+                                               kLegalFieldNames);
+        if (!status.isOK())
+            return status;
+
+        status = bsonExtractIntegerField(argsObj, kTermFieldName, &_term);
+        if (!status.isOK())
+            return status;
+
+        status = bsonExtractIntegerField(argsObj, kCandidateIdFieldName, &_candidateId);
+        if (!status.isOK())
+            return status;
+
+        return Status::OK();
+    }
+
+    void LastVote::setTerm(long long term) {
+        _term = term;
+    }
+
+    void LastVote::setCandidateId(long long candidateId) {
+        _candidateId = candidateId;
+    }
+
+    long long LastVote::getTerm() const {
+        return _term;
+    }
+
+    long long LastVote::getCandidateId() const {
+        return _candidateId;
+    }
+
+
+    BSONObj LastVote::toBSON() const {
+        BSONObjBuilder builder;
+        builder.append(kTermFieldName, _term);
+        builder.append(kCandidateIdFieldName, _candidateId);
+        return builder.obj();
+    }
+
+} // namespace repl
+} // namespace mongo
diff --git a/src/mongo/db/repl/last_vote.h b/src/mongo/db/repl/last_vote.h
new file mode 100644
index 00000000000..b2314823f00
--- /dev/null
+++ b/src/mongo/db/repl/last_vote.h
@@ -0,0 +1,56 @@
+/**
+ *    Copyright (C) 2015 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+namespace mongo {
+
+    class BSONObj;
+    class BSONObjBuilder;
+    class Status;
+
+namespace repl {
+
+    class LastVote {
+    public:
+        Status initialize(const BSONObj& argsObj);
+
+        long long getTerm() const;
+        long long getCandidateId() const;
+
+        void setTerm(long long term);
+        void setCandidateId(long long candidateId);
+        BSONObj toBSON() const;
+
+    private:
+        long long _candidateId = -1;
+        long long _term = -1;
+    };
+
+} // namespace repl
+} // namespace mongo
diff --git a/src/mongo/db/repl/repl_set_request_votes.cpp b/src/mongo/db/repl/repl_set_request_votes.cpp
index 3cada1b8d68..3d823de4930 100644
--- a/src/mongo/db/repl/repl_set_request_votes.cpp
+++ b/src/mongo/db/repl/repl_set_request_votes.cpp
@@ -59,7 +59,8 @@ namespace repl {
             }
 
             ReplSetRequestVotesResponse response;
-            status = getGlobalReplicationCoordinator()->processReplSetRequestVotes(parsedArgs,
+            status = getGlobalReplicationCoordinator()->processReplSetRequestVotes(txn,
+                                                                                   parsedArgs,
                                                                                    &response);
             response.addToBSON(&result);
             return appendCommandStatus(result, status);
diff --git a/src/mongo/db/repl/repl_set_request_votes_args.cpp b/src/mongo/db/repl/repl_set_request_votes_args.cpp
index f9efa4d41d5..da8123ab9f6 100644
--- a/src/mongo/db/repl/repl_set_request_votes_args.cpp
+++ b/src/mongo/db/repl/repl_set_request_votes_args.cpp
@@ -38,7 +38,7 @@ namespace {
 
     const std::string kCandidateIdFieldName = "candidateId";
     const std::string kCommandName = "replSetRequestVotes";
-    const std::string kConfigVersionFieldName = "cfgver";
+    const std::string kConfigVersionFieldName = "configVersion";
     const std::string kLastCommittedOpFieldName = "lastCommittedOp";
     const std::string kOkFieldName = "ok";
     const std::string kOpTimeFieldName = "ts";
@@ -187,5 +187,11 @@ namespace {
         builder->append(kReasonFieldName, _reason);
     }
 
+    BSONObj ReplSetRequestVotesResponse::toBSON() const {
+        BSONObjBuilder builder;
+        addToBSON(&builder);
+        return builder.obj();
+    }
+
 } // namespace repl
 } // namespace mongo
diff --git a/src/mongo/db/repl/repl_set_request_votes_args.h b/src/mongo/db/repl/repl_set_request_votes_args.h
index 216ef159e8a..f7152fe838e 100644
--- a/src/mongo/db/repl/repl_set_request_votes_args.h
+++ b/src/mongo/db/repl/repl_set_request_votes_args.h
@@ -62,12 +62,18 @@ namespace repl {
     public:
         Status initialize(const BSONObj& argsObj);
         
+        void setOk(bool ok) { _ok = ok; }
+        void setVoteGranted(bool voteGranted) { _voteGranted = voteGranted; }
+        void setTerm(long long term) { _term = term; }
+        void setReason(const std::string& reason) { _reason = reason; }
+
         bool getOk() const;
         long long getTerm() const;
         bool getVoteGranted() const;
         const std::string& getReason() const;
 
         void addToBSON(BSONObjBuilder* builder) const;
+        BSONObj toBSON() const;
 
     private:
         bool _ok = false;
diff --git a/src/mongo/db/repl/replication_coordinator.h b/src/mongo/db/repl/replication_coordinator.h
index 88304cdef0a..660c7b47407 100644
--- a/src/mongo/db/repl/replication_coordinator.h
+++ b/src/mongo/db/repl/replication_coordinator.h
@@ -54,6 +54,7 @@ namespace repl {
     class HandshakeArgs;
     class IsMasterResponse;
     class OplogReader;
+    class OpTime;
     class ReplSetDeclareElectionWinnerArgs;
     class ReplSetDeclareElectionWinnerResponse;
     class ReplSetHeartbeatArgs;
@@ -277,6 +278,11 @@ namespace repl {
         virtual void setMyHeartbeatMessage(const std::string& msg) = 0;
 
         /**
+         * Returns the last optime recorded by setMyLastOptimeV1.
+         */
+        virtual OpTime getMyLastOptimeV1() const = 0;
+
+        /**
          * Returns the last optime recorded by setMyLastOptime.
          */
         virtual Timestamp getMyLastOptime() const = 0;
@@ -570,7 +576,8 @@ namespace repl {
         * Handles an incoming replSetRequestVotes command.
         * Adds BSON to 'resultObj'; returns a Status with either OK or an error message.
         */
-        virtual Status processReplSetRequestVotes(const ReplSetRequestVotesArgs& args,
+        virtual Status processReplSetRequestVotes(OperationContext* txn,
+                                                  const ReplSetRequestVotesArgs& args,
                                                   ReplSetRequestVotesResponse* response) = 0;
 
         /*
diff --git a/src/mongo/db/repl/replication_coordinator_external_state.h b/src/mongo/db/repl/replication_coordinator_external_state.h
index 07fa9ed921a..bc7091a8179 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state.h
@@ -45,6 +45,8 @@ namespace mongo {
 
 namespace repl {
 
+    class LastVote;
+
     /**
      * This class represents the interface the ReplicationCoordinator uses to interact with the
      * rest of the system.  All functionality of the ReplicationCoordinatorImpl that would introduce
@@ -112,6 +114,17 @@ namespace repl {
         virtual Status storeLocalConfigDocument(OperationContext* txn, const BSONObj& config) = 0;
 
         /**
+         * Gets the replica set lastVote document from local storage, or returns an error.
+         */
+        virtual StatusWith<LastVote> loadLocalLastVoteDocument(OperationContext* txn) = 0;
+
+        /**
+         * Stores the replica set lastVote document in local storage, or returns an error.
+         */
+        virtual Status storeLocalLastVoteDocument(OperationContext* txn,
+                                                  const LastVote& lastVote) = 0;
+
+        /**
          * Sets the global opTime to be 'newTime'.
          */
         virtual void setGlobalTimestamp(const Timestamp& newTime) = 0;
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 5e3f498fdeb..fabbbf8b036 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.cpp
@@ -54,6 +54,7 @@
 #include "mongo/db/repl/oplog.h"
 #include "mongo/db/repl/replication_executor.h"
 #include "mongo/db/repl/rs_sync.h"
+#include "mongo/db/repl/last_vote.h"
 #include "mongo/db/storage/storage_engine.h"
 #include "mongo/s/d_state.h"
 #include "mongo/stdx/functional.h"
@@ -69,6 +70,8 @@ namespace repl {
 namespace {
     const char configCollectionName[] = "local.system.replset";
     const char configDatabaseName[] = "local";
+    const char lastVoteCollectionName[] = "local.replset.election";
+    const char lastVoteDatabaseName[] = "local";
     const char meCollectionName[] = "local.me";
     const char meDatabaseName[] = "local";
     const char tsFieldName[] = "ts";
@@ -199,6 +202,49 @@ namespace {
 
     }
 
+    StatusWith<LastVote> ReplicationCoordinatorExternalStateImpl::loadLocalLastVoteDocument(
+            OperationContext* txn) {
+        try {
+            MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
+                BSONObj lastVoteObj;
+                if (!Helpers::getSingleton(txn, lastVoteCollectionName, lastVoteObj)) {
+                    return StatusWith<LastVote>(
+                            ErrorCodes::NoMatchingDocument,
+                            str::stream() << "Did not find replica set lastVote document in "
+                                          << lastVoteCollectionName);
+                }
+                LastVote lastVote;
+                lastVote.initialize(lastVoteObj);
+                return StatusWith<LastVote>(lastVote);
+            } MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn,
+                                                  "load replica set lastVote",
+                                                  lastVoteCollectionName);
+        }
+        catch (const DBException& ex) {
+            return StatusWith<LastVote>(ex.toStatus());
+        }
+    }
+
+    Status ReplicationCoordinatorExternalStateImpl::storeLocalLastVoteDocument(
+            OperationContext* txn,
+            const LastVote& lastVote) {
+        BSONObj lastVoteObj = lastVote.toBSON();
+        try {
+            MONGO_WRITE_CONFLICT_RETRY_LOOP_BEGIN {
+                ScopedTransaction transaction(txn, MODE_IX);
+                Lock::DBLock dbWriteLock(txn->lockState(), lastVoteDatabaseName, MODE_X);
+                Helpers::putSingleton(txn, lastVoteCollectionName, lastVoteObj);
+                return Status::OK();
+            } MONGO_WRITE_CONFLICT_RETRY_LOOP_END(txn,
+                                                  "save replica set lastVote",
+                                                  lastVoteCollectionName);
+        }
+        catch (const DBException& ex) {
+            return ex.toStatus();
+        }
+
+    }
+
     void ReplicationCoordinatorExternalStateImpl::setGlobalTimestamp(const Timestamp& newTime) {
         setNewOptime(newTime);
     }
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 482b143f629..2c13ac634e5 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_impl.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state_impl.h
@@ -54,6 +54,8 @@ namespace repl {
         virtual bool isSelf(const HostAndPort& host);
         virtual StatusWith<BSONObj> loadLocalConfigDocument(OperationContext* txn);
         virtual Status storeLocalConfigDocument(OperationContext* txn, const BSONObj& config);
+        virtual StatusWith<LastVote> loadLocalLastVoteDocument(OperationContext* txn);
+        virtual Status storeLocalLastVoteDocument(OperationContext* txn, const LastVote& lastVote);
         virtual void setGlobalTimestamp(const Timestamp& newTime);
         virtual StatusWith<Timestamp> loadLastOpTime(OperationContext* txn);
         virtual HostAndPort getClientHostAndPort(const 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 bd4e194c5fc..3060e55f1a2 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
+++ b/src/mongo/db/repl/replication_coordinator_external_state_mock.cpp
@@ -44,11 +44,14 @@ namespace repl {
 
     ReplicationCoordinatorExternalStateMock::ReplicationCoordinatorExternalStateMock()
         : _localRsConfigDocument(ErrorCodes::NoMatchingDocument, "No local config document"),
+          _localRsLastVoteDocument(ErrorCodes::NoMatchingDocument, "No local lastVote document"),
           _lastOpTime(ErrorCodes::NoMatchingDocument, "No last oplog entry"),
-         _canAcquireGlobalSharedLock(true),
-         _storeLocalConfigDocumentStatus(Status::OK()),
-         _storeLocalConfigDocumentShouldHang(false),
-         _connectionsClosed(false) {
+          _canAcquireGlobalSharedLock(true),
+          _storeLocalConfigDocumentStatus(Status::OK()),
+          _storeLocalLastVoteDocumentStatus(Status::OK()),
+          _storeLocalConfigDocumentShouldHang(false),
+          _storeLocalLastVoteDocumentShouldHang(false),
+          _connectionsClosed(false) {
     }
 
     ReplicationCoordinatorExternalStateMock::~ReplicationCoordinatorExternalStateMock() {}
@@ -90,9 +93,9 @@ namespace repl {
             OperationContext* txn,
             const BSONObj& config) {
         {
-            boost::unique_lock<boost::mutex> lock(_shouldHangMutex);
+            boost::unique_lock<boost::mutex> lock(_shouldHangConfigMutex);
             while (_storeLocalConfigDocumentShouldHang) {
-                _shouldHangCondVar.wait(lock);
+                _shouldHangConfigCondVar.wait(lock);
             }
         }
         if (_storeLocalConfigDocumentStatus.isOK()) {
@@ -108,6 +111,33 @@ namespace repl {
         _localRsConfigDocument = localConfigDocument;
     }
 
+    StatusWith<LastVote> ReplicationCoordinatorExternalStateMock::loadLocalLastVoteDocument(
+            OperationContext* txn) {
+        return _localRsLastVoteDocument;
+    }
+
+    Status ReplicationCoordinatorExternalStateMock::storeLocalLastVoteDocument(
+            OperationContext* txn,
+            const LastVote& lastVote) {
+        {
+            boost::unique_lock<boost::mutex> lock(_shouldHangLastVoteMutex);
+            while (_storeLocalLastVoteDocumentShouldHang) {
+                _shouldHangLastVoteCondVar.wait(lock);
+            }
+        }
+        if (_storeLocalLastVoteDocumentStatus.isOK()) {
+            setLocalLastVoteDocument(StatusWith<LastVote>(lastVote));
+            return Status::OK();
+        }
+        return _storeLocalLastVoteDocumentStatus;
+    }
+
+    void ReplicationCoordinatorExternalStateMock::setLocalLastVoteDocument(
+            const StatusWith<LastVote>& localLastVoteDocument) {
+
+        _localRsLastVoteDocument = localLastVoteDocument;
+    }
+
     void ReplicationCoordinatorExternalStateMock::setGlobalTimestamp(const Timestamp& newTime) {
     }
 
@@ -126,10 +156,23 @@ namespace repl {
     }
 
     void ReplicationCoordinatorExternalStateMock::setStoreLocalConfigDocumentToHang(bool hang) {
-        boost::unique_lock<boost::mutex> lock(_shouldHangMutex);
+        boost::unique_lock<boost::mutex> lock(_shouldHangConfigMutex);
         _storeLocalConfigDocumentShouldHang = hang;
         if (!hang) {
-            _shouldHangCondVar.notify_all();
+            _shouldHangConfigCondVar.notify_all();
+        }
+    }
+
+    void ReplicationCoordinatorExternalStateMock::setStoreLocalLastVoteDocumentStatus(
+            Status status) {
+        _storeLocalLastVoteDocumentStatus = status;
+    }
+
+    void ReplicationCoordinatorExternalStateMock::setStoreLocalLastVoteDocumentToHang(bool hang) {
+        boost::unique_lock<boost::mutex> lock(_shouldHangLastVoteMutex);
+        _storeLocalLastVoteDocumentShouldHang = hang;
+        if (!hang) {
+            _shouldHangLastVoteCondVar.notify_all();
         }
     }
 
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 8f4366b7e17..48473155717 100644
--- a/src/mongo/db/repl/replication_coordinator_external_state_mock.h
+++ b/src/mongo/db/repl/replication_coordinator_external_state_mock.h
@@ -38,6 +38,7 @@
 #include "mongo/bson/timestamp.h"
 #include "mongo/db/jsobj.h"
 #include "mongo/db/repl/replication_coordinator_external_state.h"
+#include "mongo/db/repl/last_vote.h"
 #include "mongo/util/net/hostandport.h"
 
 namespace mongo {
@@ -60,6 +61,8 @@ namespace repl {
         virtual HostAndPort getClientHostAndPort(const OperationContext* txn);
         virtual StatusWith<BSONObj> loadLocalConfigDocument(OperationContext* txn);
         virtual Status storeLocalConfigDocument(OperationContext* txn, const BSONObj& config);
+        virtual StatusWith<LastVote> loadLocalLastVoteDocument(OperationContext* txn);
+        virtual Status storeLocalLastVoteDocument(OperationContext* txn, const LastVote& lastVote);
         virtual void setGlobalTimestamp(const Timestamp& newTime);
         virtual StatusWith<Timestamp> loadLastOpTime(OperationContext* txn);
         virtual void closeConnections();
@@ -81,6 +84,11 @@ namespace repl {
         void setLocalConfigDocument(const StatusWith<BSONObj>& localConfigDocument);
 
         /**
+         * Sets the return value for subsequent calls to loadLocalLastVoteDocument().
+         */
+        void setLocalLastVoteDocument(const StatusWith<LastVote>& localLastVoteDocument);
+
+        /**
          * Sets the return value for subsequent calls to getClientHostAndPort().
          */
         void setClientHostAndPort(const HostAndPort& clientHostAndPort);
@@ -102,16 +110,34 @@ namespace repl {
          */
         void setStoreLocalConfigDocumentToHang(bool hang);
 
+        /**
+         * Sets the return value for subsequent calls to storeLocalLastVoteDocument().
+         * If "status" is Status::OK(), the subsequent calls will call the underlying funtion.
+         */ 
+        void setStoreLocalLastVoteDocumentStatus(Status status);
+
+        /**
+         * Sets whether or not subsequent calls to storeLocalLastVoteDocument() should hang
+         * indefinitely or not based on the value of "hang".
+         */
+        void setStoreLocalLastVoteDocumentToHang(bool hang);
+
     private:
         StatusWith<BSONObj> _localRsConfigDocument;
+        StatusWith<LastVote> _localRsLastVoteDocument;
         StatusWith<Timestamp>  _lastOpTime;
         std::vector<HostAndPort> _selfHosts;
         bool _canAcquireGlobalSharedLock;
         Status _storeLocalConfigDocumentStatus;
+        Status _storeLocalLastVoteDocumentStatus;
         // mutex and cond var for controlling stroeLocalConfigDocument()'s hanging
-        boost::mutex _shouldHangMutex;
-        boost::condition _shouldHangCondVar;
+        boost::mutex _shouldHangConfigMutex;
+        boost::condition _shouldHangConfigCondVar;
+        // mutex and cond var for controlling stroeLocalLastVoteDocument()'s hanging
+        boost::mutex _shouldHangLastVoteMutex;
+        boost::condition _shouldHangLastVoteCondVar;
         bool _storeLocalConfigDocumentShouldHang;
+        bool _storeLocalLastVoteDocumentShouldHang;
         bool _connectionsClosed;
         HostAndPort _clientHostAndPort;
     };
diff --git a/src/mongo/db/repl/replication_coordinator_impl.cpp b/src/mongo/db/repl/replication_coordinator_impl.cpp
index f8a4031317e..bb023078021 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl.cpp
@@ -57,6 +57,7 @@
 #include "mongo/db/repl/rslog.h"
 #include "mongo/db/repl/topology_coordinator.h"
 #include "mongo/db/repl/update_position_args.h"
+#include "mongo/db/repl/last_vote.h"
 #include "mongo/db/server_options.h"
 #include "mongo/db/write_concern_options.h"
 #include "mongo/stdx/functional.h"
@@ -68,7 +69,7 @@
 
 namespace mongo {
 namespace repl {
-
+    
 namespace {
     typedef StatusWith<ReplicationExecutor::CallbackHandle> CBHStatus;
 
@@ -226,8 +227,24 @@ namespace {
         return _rsConfig;
     }
 
+    void ReplicationCoordinatorImpl::_updateLastVote(const LastVote& lastVote) {
+        _topCoord->loadLastVote(lastVote);
+    }
+
     bool ReplicationCoordinatorImpl::_startLoadLocalConfig(OperationContext* txn) {
 
+        StatusWith<LastVote> lastVote = _externalState->loadLocalLastVoteDocument(txn);
+        if (!lastVote.isOK()) {
+            log() << "Did not find local voted for document at startup;  " << lastVote.getStatus();
+        }
+        else {
+            LastVote vote = lastVote.getValue();
+            _replExecutor.scheduleWork(
+                    stdx::bind(&ReplicationCoordinatorImpl::_updateLastVote,
+                               this,
+                               vote));
+        }
+
         StatusWith<BSONObj> cfg = _externalState->loadLocalConfigDocument(txn);
         if (!cfg.isOK()) {
             log() << "Did not find local replica set configuration document at startup;  " <<
@@ -736,6 +753,16 @@ namespace {
         _externalState->forwardSlaveProgress(); // Must do this outside _mutex
     }
 
+    OpTime ReplicationCoordinatorImpl::getMyLastOptimeV1() const {
+        boost::lock_guard<boost::mutex> lock(_mutex);
+        return _getMyLastOptimeV1_inlock();
+    }
+
+    // TODO(dannenberg): _slaveInfo should store OpTimes and they shouldn't always have term=0
+    OpTime ReplicationCoordinatorImpl::_getMyLastOptimeV1_inlock() const {
+        return OpTime(_slaveInfo[_getMyIndexInSlaveInfo_inlock()].opTime, 0);
+    }
+
     Timestamp ReplicationCoordinatorImpl::getMyLastOptime() const {
         boost::lock_guard<boost::mutex> lock(_mutex);
         return _getMyLastOptime_inlock();
@@ -2411,11 +2438,52 @@ namespace {
     }
 
     Status ReplicationCoordinatorImpl::processReplSetRequestVotes(
-        const ReplSetRequestVotesArgs& args, ReplSetRequestVotesResponse* response) {
+            OperationContext* txn,
+            const ReplSetRequestVotesArgs& args,
+            ReplSetRequestVotesResponse* response) {
         if (!isV1ElectionProtocol()) {
             return {ErrorCodes::BadValue, "not using election protocol v1"};
         }
-        return {ErrorCodes::CommandNotFound, "not implemented"};
+        Status result{ErrorCodes::InternalError, "didn't set status in processReplSetRequestVotes"};
+        CBHStatus cbh = _replExecutor.scheduleWork(
+            stdx::bind(&ReplicationCoordinatorImpl::_processReplSetRequestVotes_finish,
+                       this,
+                       stdx::placeholders::_1,
+                       args,
+                       response,
+                       &result));
+        if (cbh.getStatus() == ErrorCodes::ShutdownInProgress) {
+            return cbh.getStatus();
+        }
+        _replExecutor.wait(cbh.getValue());
+        if (response->getVoteGranted()) {
+            LastVote lastVote;
+            lastVote.setTerm(args.getTerm());
+            lastVote.setCandidateId(args.getCandidateId());
+
+            Status status = _externalState->storeLocalConfigDocument(txn, lastVote.toBSON());
+            if (!status.isOK()) {
+                error() << "replSetReconfig failed to store config document; " << status;
+                return status;
+            }
+
+        }
+        return result;
+    }
+
+    void ReplicationCoordinatorImpl::_processReplSetRequestVotes_finish(
+            const ReplicationExecutor::CallbackData& cbData,
+            const ReplSetRequestVotesArgs& args,
+            ReplSetRequestVotesResponse* response,
+            Status* result) {
+        if (cbData.status == ErrorCodes::CallbackCanceled) {
+            *result = Status(ErrorCodes::ShutdownInProgress, "replication system is shutting down");
+            return;
+        }
+
+        boost::unique_lock<boost::mutex> lk(_mutex);
+        _topCoord->processReplSetRequestVotes(args, response, getMyLastOptimeV1());
+        *result = Status::OK();
     }
 
     Status ReplicationCoordinatorImpl::processReplSetDeclareElectionWinner(
diff --git a/src/mongo/db/repl/replication_coordinator_impl.h b/src/mongo/db/repl/replication_coordinator_impl.h
index aa2c7b2dd05..c445327010b 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.h
+++ b/src/mongo/db/repl/replication_coordinator_impl.h
@@ -39,6 +39,7 @@
 #include "mongo/db/service_context.h"
 #include "mongo/db/repl/member_state.h"
 #include "mongo/db/repl/data_replicator.h"
+#include "mongo/db/repl/optime.h"
 #include "mongo/db/repl/replica_set_config.h"
 #include "mongo/db/repl/replication_coordinator.h"
 #include "mongo/db/repl/replication_coordinator_external_state.h"
@@ -66,6 +67,7 @@ namespace repl {
     class ReplicaSetConfig;
     class SyncSourceFeedback;
     class TopologyCoordinator;
+    class LastVote;
 
     class ReplicationCoordinatorImpl : public ReplicationCoordinator,
                                        public KillOpListenerInterface {
@@ -154,6 +156,8 @@ namespace repl {
 
         virtual Timestamp getMyLastOptime() const;
 
+        virtual OpTime getMyLastOptimeV1() const;
+
         virtual OID getElectionId();
 
         virtual OID getMyRID() const;
@@ -237,7 +241,8 @@ namespace repl {
 
         virtual Timestamp getLastCommittedOpTime() const;
 
-        virtual Status processReplSetRequestVotes(const ReplSetRequestVotesArgs& args,
+        virtual Status processReplSetRequestVotes(OperationContext* txn,
+                                                  const ReplSetRequestVotesArgs& args,
                                                   ReplSetRequestVotesResponse* response);
 
         virtual Status processReplSetDeclareElectionWinner(
@@ -453,6 +458,15 @@ namespace repl {
                 Status* result);
 
         /**
+         * Bottom half of processReplSetRequestVotes.
+         */
+        void _processReplSetRequestVotes_finish(
+                const ReplicationExecutor::CallbackData& cbData,
+                const ReplSetRequestVotesArgs& args,
+                ReplSetRequestVotesResponse* response,
+                Status* result);
+
+        /**
          * Scheduled to cause the ReplicationCoordinator to reconsider any state that might
          * need to change as a result of time passing - for instance becoming PRIMARY when a single
          * node replica set member's stepDown period ends.
@@ -519,6 +533,7 @@ namespace repl {
 
         Timestamp _getMyLastOptime_inlock() const;
 
+        OpTime _getMyLastOptimeV1_inlock() const;
 
         /**
          * Bottom half of setFollowerMode.
@@ -607,6 +622,15 @@ namespace repl {
         MemberState _getMemberState_inlock() const;
 
         /**
+         * Callback that gives the TopologyCoordinator an initial LastVote document from
+         * local storage.
+         *
+         * Called only during replication startup. All other updates come from the
+         * TopologyCoordinator itself.
+         */
+        void _updateLastVote(const LastVote& lastVote);
+
+        /**
          * Starts loading the replication configuration from local storage, and if it is valid,
          * schedules a callback (of _finishLoadLocalConfig) to set it as the current replica set
          * config (sets _rsConfig and _thisMembersConfigIndex).
@@ -930,6 +954,7 @@ namespace repl {
 
         // Data Replicator used to replicate data
         DataReplicator _dr;                                                               // (S)
+
     };
 
 } // namespace repl
diff --git a/src/mongo/db/repl/replication_coordinator_impl_test.cpp b/src/mongo/db/repl/replication_coordinator_impl_test.cpp
index 6411cb8ea09..ca87ebf9fe3 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_test.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_test.cpp
@@ -100,7 +100,7 @@ namespace {
         startCapturingLogMessages();
         start();
         stopCapturingLogMessages();
-        ASSERT_EQUALS(1, countLogLinesContaining("Did not find local "));
+        ASSERT_EQUALS(2, countLogLinesContaining("Did not find local "));
         ASSERT_EQUALS(MemberState::RS_STARTUP, getReplCoord()->getMemberState().s);
     }
 
diff --git a/src/mongo/db/repl/replication_coordinator_mock.cpp b/src/mongo/db/repl/replication_coordinator_mock.cpp
index fd36c227898..9d7f28e62af 100644
--- a/src/mongo/db/repl/replication_coordinator_mock.cpp
+++ b/src/mongo/db/repl/replication_coordinator_mock.cpp
@@ -33,6 +33,7 @@
 #include "mongo/base/status.h"
 #include "mongo/db/write_concern_options.h"
 #include "mongo/db/repl/replica_set_config.h"
+#include "mongo/db/repl/optime.h"
 #include "mongo/util/assert_util.h"
 
 namespace mongo {
@@ -135,6 +136,10 @@ namespace repl {
 
     void ReplicationCoordinatorMock::resetMyLastOptime() {}
 
+    OpTime ReplicationCoordinatorMock::getMyLastOptimeV1() const {
+        return OpTime();
+    }
+
     Timestamp ReplicationCoordinatorMock::getMyLastOptime() const {
         // TODO
         return Timestamp();
@@ -300,8 +305,9 @@ namespace repl {
     }
 
     Status ReplicationCoordinatorMock::processReplSetRequestVotes(
-        const ReplSetRequestVotesArgs& args,
-        ReplSetRequestVotesResponse* response) {
+            OperationContext* txn,
+            const ReplSetRequestVotesArgs& args,
+            ReplSetRequestVotesResponse* response) {
         return Status::OK();
     }
 
diff --git a/src/mongo/db/repl/replication_coordinator_mock.h b/src/mongo/db/repl/replication_coordinator_mock.h
index 6b346ab449e..79cf56507c8 100644
--- a/src/mongo/db/repl/replication_coordinator_mock.h
+++ b/src/mongo/db/repl/replication_coordinator_mock.h
@@ -99,6 +99,8 @@ namespace repl {
 
         virtual void setMyHeartbeatMessage(const std::string& msg);
 
+        virtual OpTime getMyLastOptimeV1() const;
+
         virtual Timestamp getMyLastOptime() const;
 
         virtual OID getElectionId();
@@ -182,7 +184,8 @@ namespace repl {
 
         virtual Timestamp getLastCommittedOpTime() const;
 
-        virtual Status processReplSetRequestVotes(const ReplSetRequestVotesArgs& args,
+        virtual Status processReplSetRequestVotes(OperationContext* txn,
+                                                  const ReplSetRequestVotesArgs& args,
                                                   ReplSetRequestVotesResponse* response);
 
         virtual Status processReplSetDeclareElectionWinner(
diff --git a/src/mongo/db/repl/topology_coordinator.h b/src/mongo/db/repl/topology_coordinator.h
index 595138a20e7..a9222a84085 100644
--- a/src/mongo/db/repl/topology_coordinator.h
+++ b/src/mongo/db/repl/topology_coordinator.h
@@ -48,6 +48,7 @@ namespace repl {
     class ReplSetHeartbeatArgs;
     class ReplicaSetConfig;
     class TagSubgroup;
+    class LastVote;
     struct MemberState;
 
     /**
@@ -367,6 +368,13 @@ namespace repl {
         virtual void summarizeAsHtml(ReplSetHtmlSummary* output) = 0;
 
         /**
+         * Prepares a ReplSetRequestVotesResponse.
+         */
+        virtual void processReplSetRequestVotes(const ReplSetRequestVotesArgs& args,
+                                                ReplSetRequestVotesResponse* response,
+                                                const OpTime& lastAppliedOpTime) = 0;
+
+        /**
          * Determines whether or not the newly elected primary is valid from our perspective.
          * If it is, sets the _currentPrimaryIndex and term to the received values.
          * If it is not, return ErrorCode::BadValue and the current term from our perspective.
@@ -376,6 +384,13 @@ namespace repl {
                 const ReplSetDeclareElectionWinnerArgs& args,
                 long long* responseTerm) = 0;
 
+        /**
+         * Loads an initial LastVote document, which was read from local storage.
+         *
+         * Called only during replication startup. All other updates are done internally.
+         */
+        virtual void loadLastVote(const LastVote& lastVote) = 0;
+
     protected:
         TopologyCoordinator() {}
     };
diff --git a/src/mongo/db/repl/topology_coordinator_impl.cpp b/src/mongo/db/repl/topology_coordinator_impl.cpp
index 491516b44f8..7dde549b12b 100644
--- a/src/mongo/db/repl/topology_coordinator_impl.cpp
+++ b/src/mongo/db/repl/topology_coordinator_impl.cpp
@@ -42,6 +42,7 @@
 #include "mongo/db/repl/repl_set_heartbeat_args.h"
 #include "mongo/db/repl/repl_set_heartbeat_response.h"
 #include "mongo/db/repl/repl_set_html_summary.h"
+#include "mongo/db/repl/repl_set_request_votes_args.h"
 #include "mongo/db/repl/replication_executor.h"
 #include "mongo/db/repl/rslog.h"
 #include "mongo/db/server_parameters.h"
@@ -55,7 +56,7 @@ namespace repl {
 
     using std::vector;
 
-    const Seconds TopologyCoordinatorImpl::LastVote::leaseTime = Seconds(30);
+    const Seconds TopologyCoordinatorImpl::VoteLease::leaseTime = Seconds(30);
 
 namespace {
 
@@ -124,7 +125,6 @@ namespace {
 
     TopologyCoordinatorImpl::TopologyCoordinatorImpl(Seconds maxSyncSourceLagSecs) :
         _role(Role::follower),
-        _term(0),
         _currentPrimaryIndex(-1),
         _forceSyncSourceIndex(-1),
         _maxSyncSourceLagSecs(maxSyncSourceLagSecs),
@@ -622,17 +622,17 @@ namespace {
                   << highestPriority->getHostAndPort().toString();
             vote = -10000;
         }
-        else if (_lastVote.when.millis + LastVote::leaseTime.total_milliseconds() >= now.millis &&
-                 _lastVote.whoId != args.whoid) {
+        else if (_voteLease.when.millis + VoteLease::leaseTime.total_milliseconds() >= now.millis &&
+                 _voteLease.whoId != args.whoid) {
             log() << "replSet voting no for "
                   <<  hopeful->getHostAndPort().toString()
-                  << "; voted for " << _lastVote.whoHostAndPort.toString() << ' '
-                  << (now.millis - _lastVote.when.millis) / 1000 << " secs ago";
+                  << "; voted for " << _voteLease.whoHostAndPort.toString() << ' '
+                  << (now.millis - _voteLease.when.millis) / 1000 << " secs ago";
         }
         else {
-            _lastVote.when = now;
-            _lastVote.whoId = args.whoid;
-            _lastVote.whoHostAndPort = hopeful->getHostAndPort();
+            _voteLease.when = now;
+            _voteLease.whoId = args.whoid;
+            _voteLease.whoHostAndPort = hopeful->getHostAndPort();
             vote = _selfConfig().getNumVotes();
             invariant(hopeful->getId() == args.whoid);
             if (vote > 0) {
@@ -993,7 +993,7 @@ namespace {
                               << (latestOpTime.getSecs() - highestPriorityMemberOptime.getSecs())
                               << " seconds behind me";
                         const Date_t until = now +
-                            LastVote::leaseTime.total_milliseconds() +
+                            VoteLease::leaseTime.total_milliseconds() +
                             kHeartbeatInterval.total_milliseconds();
                         if (_electionSleepUntil < until) {
                             _electionSleepUntil = until;
@@ -1740,9 +1740,9 @@ namespace {
         if (_stepDownUntil > now) {
             result |= StepDownPeriodActive;
         }
-        if (_lastVote.whoId != -1 &&
-                _lastVote.whoId !=_rsConfig.getMemberAt(_selfIndex).getId() &&
-                _lastVote.when.millis + LastVote::leaseTime.total_milliseconds() >= now.millis) {
+        if (_voteLease.whoId != -1 &&
+                _voteLease.whoId !=_rsConfig.getMemberAt(_selfIndex).getId() &&
+                _voteLease.when.millis + VoteLease::leaseTime.total_milliseconds() >= now.millis) {
             result |= VotedTooRecently;
         }
 
@@ -1770,7 +1770,7 @@ namespace {
                 ss << "; ";
             }
             hasWrittenToStream = true;
-            ss << "I recently voted for " << _lastVote.whoHostAndPort.toString();
+            ss << "I recently voted for " << _voteLease.whoHostAndPort.toString();
         }
         if (ur & CannotSeeMajority) {
             if (hasWrittenToStream) {
@@ -1879,16 +1879,16 @@ namespace {
             return false;
         }
         int selfId = _selfConfig().getId();
-        if ((_lastVote.when + LastVote::leaseTime.total_milliseconds() >= now) 
-            && (_lastVote.whoId != selfId)) {
+        if ((_voteLease.when + VoteLease::leaseTime.total_milliseconds() >= now) 
+            && (_voteLease.whoId != selfId)) {
             log() << "not voting yea for " << selfId <<
-                " voted for " << _lastVote.whoHostAndPort.toString() << ' ' << 
-                (now - _lastVote.when) / 1000 << " secs ago";
+                " voted for " << _voteLease.whoHostAndPort.toString() << ' ' << 
+                (now - _voteLease.when) / 1000 << " secs ago";
             return false;
         }
-        _lastVote.when = now;
-        _lastVote.whoId = selfId;
-        _lastVote.whoHostAndPort = _selfConfig().getHostAndPort();
+        _voteLease.when = now;
+        _voteLease.whoId = selfId;
+        _voteLease.whoHostAndPort = _selfConfig().getHostAndPort();
         return true;
     }
 
@@ -1933,10 +1933,10 @@ namespace {
         _electionId = OID();
         _role = Role::follower;
 
-        // Clear lastVote time, if we voted for ourselves in this election.
+        // Clear voteLease time, if we voted for ourselves in this election.
         // This will allow us to vote for others.
-        if (_lastVote.whoId == _selfConfig().getId()) {
-            _lastVote.when = 0;
+        if (_voteLease.whoId == _selfConfig().getId()) {
+            _voteLease.when = 0;
         }
     }
 
@@ -2104,6 +2104,42 @@ namespace {
         output->setSelfHeartbeatMessage(_hbmsg);
     }
 
+    void TopologyCoordinatorImpl::processReplSetRequestVotes(
+            const ReplSetRequestVotesArgs& args,
+            ReplSetRequestVotesResponse* response,
+            const OpTime& lastAppliedOpTime) {
+        response->setOk(true);
+        response->setTerm(_term);
+
+        if (args.getTerm() < _term) {
+            response->setVoteGranted(false);
+            response->setReason("candidate's term is lower than mine");
+        }
+        else if (args.getConfigVersion() != _rsConfig.getConfigVersion()) {
+            response->setVoteGranted(false);
+            response->setReason("candidate's config version differs from mine");
+        }
+        else if (args.getSetName() != _rsConfig.getReplSetName()) {
+            response->setVoteGranted(false);
+            response->setReason("candidate's set name differs from mine");
+        }
+        // TODO(dannenberg): switch comparison to OpTimes once lastAppliedOpTime is an OpTime again
+        else if (args.getLastCommittedOp() < lastAppliedOpTime) {
+            response->setVoteGranted(false);
+            response->setReason("candidate's data is staler than mine");
+        }
+        else if (_lastVote.getTerm() == args.getTerm()) {
+            response->setVoteGranted(false);
+            response->setReason("already voted for another candidate this term");
+        }
+        else {
+            _lastVote.setTerm(args.getTerm());
+            _lastVote.setCandidateId(args.getCandidateId());
+            response->setVoteGranted(true);
+        }
+
+    }
+
     Status TopologyCoordinatorImpl::processReplSetDeclareElectionWinner(
             const ReplSetDeclareElectionWinnerArgs& args,
             long long* responseTerm) {
@@ -2127,5 +2163,9 @@ namespace {
         return Status::OK();
     }
 
+    void TopologyCoordinatorImpl::loadLastVote(const LastVote& lastVote) {
+        _lastVote = lastVote;
+    }
+
 } // namespace repl
 } // namespace mongo
diff --git a/src/mongo/db/repl/topology_coordinator_impl.h b/src/mongo/db/repl/topology_coordinator_impl.h
index 69f6b31df37..39d186c7308 100644
--- a/src/mongo/db/repl/topology_coordinator_impl.h
+++ b/src/mongo/db/repl/topology_coordinator_impl.h
@@ -37,6 +37,7 @@
 #include "mongo/db/repl/replica_set_config.h"
 #include "mongo/db/repl/replication_coordinator.h"
 #include "mongo/db/repl/topology_coordinator.h"
+#include "mongo/db/repl/last_vote.h"
 #include "mongo/util/time_support.h"
 
 namespace mongo {
@@ -190,9 +191,14 @@ namespace repl {
                                                const Timestamp& lastCommitttedOpTime) const;
         Status processReplSetDeclareElectionWinner(const ReplSetDeclareElectionWinnerArgs& args,
                                                    long long* responseTerm);
+        virtual void processReplSetRequestVotes(const ReplSetRequestVotesArgs& args,
+                                                ReplSetRequestVotesResponse* response,
+                                                const OpTime& lastAppliedOpTime);
 
         virtual void summarizeAsHtml(ReplSetHtmlSummary* output);
 
+        virtual void loadLastVote(const LastVote& lastVote);
+
         ////////////////////////////////////////////////////////////
         //
         // Test support methods
@@ -335,7 +341,7 @@ namespace repl {
 
         // This node's election term.  The term is used as part of the consensus algorithm to elect
         // and maintain one primary (leader) node in the cluster.
-        long long _term;
+        long long _term = -1;
 
         // the index of the member we currently believe is primary, if one exists, otherwise -1
         int _currentPrimaryIndex;
@@ -393,15 +399,18 @@ namespace repl {
         PingMap _pings;
 
         // Last vote info from the election
-        struct LastVote {
+        struct VoteLease {
 
             static const Seconds leaseTime;
 
-            LastVote() : when(0), whoId(-1) { }
+            VoteLease() : when(0), whoId(-1) { }
             Date_t when;
             int whoId;
             HostAndPort whoHostAndPort;
-        } _lastVote;
+        } _voteLease;
+
+        // V1 last vote info for elections
+        LastVote _lastVote;
 
     };
 
diff --git a/src/mongo/db/repl/topology_coordinator_impl_test.cpp b/src/mongo/db/repl/topology_coordinator_impl_test.cpp
index ce99ca62ee9..3d314251934 100644
--- a/src/mongo/db/repl/topology_coordinator_impl_test.cpp
+++ b/src/mongo/db/repl/topology_coordinator_impl_test.cpp
@@ -35,6 +35,8 @@
 #include "mongo/db/repl/member_heartbeat_data.h"
 #include "mongo/db/repl/repl_set_heartbeat_args.h"
 #include "mongo/db/repl/repl_set_heartbeat_response.h"
+#include "mongo/db/repl/repl_set_declare_election_winner_args.h"
+#include "mongo/db/repl/repl_set_request_votes_args.h"
 #include "mongo/db/repl/topology_coordinator.h"
 #include "mongo/db/repl/topology_coordinator_impl.h"
 #include "mongo/unittest/unittest.h"
@@ -4098,6 +4100,132 @@ namespace {
         logger::globalLogDomain()->setMinimumLoggedSeverity(logger::LogSeverity::Log());
     }
 
+    TEST_F(TopoCoordTest, ProcessRequestVotesTwoRequestsForSameTerm) {
+        updateConfig(BSON("_id" << "rs0" <<
+                          "version" << 1 <<
+                          "members" << BSON_ARRAY(
+                              BSON("_id" << 10 << "host" << "hself") <<
+                              BSON("_id" << 20 << "host" << "h2") <<
+                              BSON("_id" << 30 << "host" << "h3"))),
+                     0);
+        setSelfMemberState(MemberState::RS_SECONDARY);
+
+        ReplSetRequestVotesArgs args;
+        args.initialize(BSON("replSetRequestVotes" << 1
+                          << "setName" << "rs0"
+                          << "term" << 1LL
+                          << "candidateId" << 10LL
+                          << "configVersion" << 1LL
+                          << "lastCommittedOp" << BSON ("ts" << Timestamp(10, 0)
+                                                     << "term" << 0LL)));
+        ReplSetRequestVotesResponse response;
+        OpTime lastAppliedOpTime;
+
+        getTopoCoord().processReplSetRequestVotes(args, &response, lastAppliedOpTime);
+        ASSERT_EQUALS("", response.getReason());
+        ASSERT_TRUE(response.getVoteGranted());
+    
+        ReplSetRequestVotesArgs args2;
+        args2.initialize(BSON("replSetRequestVotes" << 1
+                           << "setName" << "rs0"
+                           << "term" << 1LL
+                           << "candidateId" << 20LL
+                           << "configVersion" << 1LL
+                           << "lastCommittedOp" << BSON ("ts" << Timestamp(10, 0)
+                                                      << "term" << 0LL)));
+        ReplSetRequestVotesResponse response2;
+
+        // different candidate same term, should be a problem
+        getTopoCoord().processReplSetRequestVotes(args2, &response2, lastAppliedOpTime);
+        ASSERT_EQUALS("already voted for another candidate this term", response2.getReason());
+        ASSERT_FALSE(response2.getVoteGranted());
+    
+    }
+
+    TEST_F(TopoCoordTest, ProcessRequestVotesBadCommands) {
+        updateConfig(BSON("_id" << "rs0" <<
+                          "version" << 1 <<
+                          "members" << BSON_ARRAY(
+                              BSON("_id" << 10 << "host" << "hself") <<
+                              BSON("_id" << 20 << "host" << "h2") <<
+                              BSON("_id" << 30 << "host" << "h3"))),
+                     0);
+        setSelfMemberState(MemberState::RS_SECONDARY);
+
+        // mismatched setName
+        ReplSetRequestVotesArgs args;
+        args.initialize(BSON("replSetRequestVotes" << 1
+                          << "setName" << "wrongName"
+                          << "term" << 1LL
+                          << "candidateId" << 10LL
+                          << "configVersion" << 1LL
+                          << "lastCommittedOp" << BSON ("ts" << Timestamp(10, 0)
+                                                     << "term" << 0LL)));
+        ReplSetRequestVotesResponse response;
+        OpTime lastAppliedOpTime;
+
+        getTopoCoord().processReplSetRequestVotes(args, &response, lastAppliedOpTime);
+        ASSERT_EQUALS("candidate's set name differs from mine", response.getReason());
+        ASSERT_FALSE(response.getVoteGranted());
+    
+        // mismatched configVersion
+        ReplSetRequestVotesArgs args2;
+        args2.initialize(BSON("replSetRequestVotes" << 1
+                           << "setName" << "rs0"
+                           << "term" << 1LL
+                           << "candidateId" << 20LL
+                           << "configVersion" << 0LL
+                           << "lastCommittedOp" << BSON ("ts" << Timestamp(10, 0)
+                                                      << "term" << 0LL)));
+        ReplSetRequestVotesResponse response2;
+
+        getTopoCoord().processReplSetRequestVotes(args2, &response2, lastAppliedOpTime);
+        ASSERT_EQUALS("candidate's config version differs from mine", response2.getReason());
+        ASSERT_FALSE(response2.getVoteGranted());
+    
+        // set term higher by receiving a replSetDeclareElectionWinnerCommand
+        ReplSetDeclareElectionWinnerArgs winnerArgs;
+        winnerArgs.initialize(BSON("replSetDeclareElectionWinner" << 1
+                                << "setName" << "rs0"
+                                << "term" << 2
+                                << "winnerId" << 30));
+        long long responseTerm;
+        ASSERT_OK(getTopoCoord().processReplSetDeclareElectionWinner(winnerArgs, &responseTerm));
+        ASSERT_EQUALS(2, responseTerm);
+
+        // stale term
+        ReplSetRequestVotesArgs args3;
+        args3.initialize(BSON("replSetRequestVotes" << 1
+                           << "setName" << "rs0"
+                           << "term" << 1LL
+                           << "candidateId" << 20LL
+                           << "configVersion" << 1LL
+                           << "lastCommittedOp" << BSON ("ts" << Timestamp(10, 0)
+                                                      << "term" << 0LL)));
+        ReplSetRequestVotesResponse response3;
+
+        getTopoCoord().processReplSetRequestVotes(args3, &response3, lastAppliedOpTime);
+        ASSERT_EQUALS("candidate's term is lower than mine", response3.getReason());
+        ASSERT_EQUALS(2, response3.getTerm());
+        ASSERT_FALSE(response3.getVoteGranted());
+    
+        // stale OpTime
+        ReplSetRequestVotesArgs args4;
+        args4.initialize(BSON("replSetRequestVotes" << 1
+                           << "setName" << "rs0"
+                           << "term" << 3LL
+                           << "candidateId" << 20LL
+                           << "configVersion" << 1LL
+                           << "lastCommittedOp" << BSON ("ts" << Timestamp(10, 0)
+                                                      << "term" << 0LL)));
+        ReplSetRequestVotesResponse response4;
+        OpTime lastAppliedOpTime2 = {Timestamp(20, 0), 0};
+
+        getTopoCoord().processReplSetRequestVotes(args4, &response4, lastAppliedOpTime2);
+        ASSERT_EQUALS("candidate's data is staler than mine", response4.getReason());
+        ASSERT_FALSE(response4.getVoteGranted());
+    }
+
 }  // namespace
 }  // namespace repl
 }  // namespace mongo
diff --git a/src/mongo/db/repl/vote_requester.cpp b/src/mongo/db/repl/vote_requester.cpp
new file mode 100644
index 00000000000..ecabc80fbd5
--- /dev/null
+++ b/src/mongo/db/repl/vote_requester.cpp
@@ -0,0 +1,156 @@
+/**
+ *    Copyright 2015 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#define MONGO_LOG_DEFAULT_COMPONENT ::mongo::logger::LogComponent::kReplication
+
+#include "mongo/platform/basic.h"
+
+#include "mongo/db/repl/vote_requester.h"
+
+#include "mongo/base/status.h"
+#include "mongo/db/repl/repl_set_request_votes_args.h"
+#include "mongo/db/repl/replication_executor.h"
+#include "mongo/db/repl/scatter_gather_runner.h"
+#include "mongo/rpc/get_status_from_command_result.h"
+#include "mongo/util/log.h"
+
+namespace mongo {
+namespace repl {
+
+    VoteRequester::Algorithm::Algorithm(const ReplicaSetConfig& rsConfig,
+                                        long long candidateId,
+                                        long long term,
+                                        OpTime lastOplogEntry) :
+            _rsConfig(rsConfig),
+            _candidateId(candidateId),
+            _term(term),
+            _lastOplogEntry(lastOplogEntry) {
+
+        // populate targets with all voting members that aren't this node
+        for (auto member = _rsConfig.membersBegin(); member != _rsConfig.membersEnd(); member++) {
+            if (member->isVoter() && member->getId() != candidateId) {
+                _targets.push_back(member->getHostAndPort());
+            }
+        }
+    }
+
+    VoteRequester::Algorithm::~Algorithm() {}
+
+    std::vector<ReplicationExecutor::RemoteCommandRequest>
+    VoteRequester::Algorithm::getRequests() const {
+        BSONObjBuilder requestVotesCmdBuilder;
+        requestVotesCmdBuilder.append("replSetDeclareElectionWinner", 1);
+        requestVotesCmdBuilder.append("setName", _rsConfig.getReplSetName());
+        requestVotesCmdBuilder.append("term", _term);
+        requestVotesCmdBuilder.append("candidateId", _candidateId);
+        requestVotesCmdBuilder.append("configVersion", _rsConfig.getConfigVersion());
+
+        BSONObjBuilder lastCommittedOp(requestVotesCmdBuilder.subobjStart("lastCommittedOp"));
+        lastCommittedOp.append("ts", _lastOplogEntry.getTimestamp());
+        lastCommittedOp.append("term", _lastOplogEntry.getTerm());
+        lastCommittedOp.done();
+
+        const BSONObj requestVotesCmd = requestVotesCmdBuilder.obj();
+
+        std::vector<ReplicationExecutor::RemoteCommandRequest> requests;
+        for (const auto& target : _targets) {
+            requests.push_back(ReplicationExecutor::RemoteCommandRequest(
+                        target,
+                        "admin",
+                        requestVotesCmd,
+                        Milliseconds(30*1000)));   // trying to match current Socket timeout
+        }
+
+        return requests;
+    }
+
+    void VoteRequester::Algorithm::processResponse(
+            const ReplicationExecutor::RemoteCommandRequest& request,
+            const ResponseStatus& response) {
+        _responsesProcessed++;
+        if (!response.isOK()) { // failed response
+            log() << "VoteRequester: Got failed response from " << request.target
+                  << ": " << response.getStatus();
+        }
+        else {
+            ReplSetRequestVotesResponse voteResponse;
+            voteResponse.initialize(response.getValue().data);
+            if (voteResponse.getVoteGranted()) {
+                _votes++;
+            }
+            else {
+                log() << "VoteRequester: Got no vote from " << request.target
+                      << " because: " << voteResponse.getReason();
+            }
+
+            if (voteResponse.getTerm() > _term) {
+                _failed = true;
+                _status = {ErrorCodes::BadValue,
+                           "running for a stale term"};
+            }
+        }
+
+        if (_responsesProcessed == static_cast<int>(_targets.size()) && // all responses obtained
+                !hasReceivedSufficientResponses()) {
+            _failed = true;
+            _status = {ErrorCodes::IllegalOperation,
+                       "received insufficient votes"};
+        }
+    }
+
+    bool VoteRequester::Algorithm::hasReceivedSufficientResponses() const {
+        return _failed || _votes == _rsConfig.getMajorityVoteCount();
+    }
+
+    VoteRequester::VoteRequester() : _isCanceled(false) {}
+    VoteRequester::~VoteRequester() {}
+
+    StatusWith<ReplicationExecutor::EventHandle> VoteRequester::start(
+            ReplicationExecutor* executor,
+            const ReplicaSetConfig& rsConfig,
+            long long candidateId,
+            long long term,
+            OpTime lastOplogEntry,
+            const stdx::function<void ()>& onCompletion) {
+
+        _algorithm.reset(new Algorithm(rsConfig,
+                                       candidateId,
+                                       term,
+                                       lastOplogEntry));
+        _runner.reset(new ScatterGatherRunner(_algorithm.get()));
+        return _runner->start(executor, onCompletion);
+    }
+
+    void VoteRequester::cancel(ReplicationExecutor* executor) {
+        _isCanceled = true;
+        _runner->cancel(executor);
+    }
+
+
+} // namespace repl
+} // namespace mongo
diff --git a/src/mongo/db/repl/vote_requester.h b/src/mongo/db/repl/vote_requester.h
new file mode 100644
index 00000000000..72c4f90c3f7
--- /dev/null
+++ b/src/mongo/db/repl/vote_requester.h
@@ -0,0 +1,123 @@
+/**
+ *    Copyright (C) 2015 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#pragma once
+
+#include <memory>
+#include <vector>
+
+#include "mongo/base/disallow_copying.h"
+#include "mongo/bson/timestamp.h"
+#include "mongo/db/repl/optime.h"
+#include "mongo/db/repl/replica_set_config.h"
+#include "mongo/db/repl/replication_executor.h"
+#include "mongo/db/repl/scatter_gather_algorithm.h"
+#include "mongo/stdx/functional.h"
+
+namespace mongo {
+
+    class Status;
+
+namespace repl {
+
+    class ScatterGatherRunner;
+    class ReplSetDeclareRequestVotesArgs;
+
+    class VoteRequester {
+        MONGO_DISALLOW_COPYING(VoteRequester);
+    public:
+
+        class Algorithm : public ScatterGatherAlgorithm {
+        public:
+            Algorithm(const ReplicaSetConfig& rsConfig,
+                      long long candidateId,
+                      long long term,
+                      OpTime lastOplogEntry);
+            virtual ~Algorithm();
+            virtual std::vector<ReplicationExecutor::RemoteCommandRequest> getRequests() const;
+            virtual void processResponse(
+                    const ReplicationExecutor::RemoteCommandRequest& request,
+                    const ResponseStatus& response);
+            virtual bool hasReceivedSufficientResponses() const;
+
+            /**
+             * Returns BadValue if the term for which we are running is statel, IllegalOperation if
+             * insufficient votes are received, and Status::OK if we've won the election.
+             * 
+             * It is invalid to call this before hasReceivedSufficeintResponses returns true.
+             */
+            Status getStatus() const { return _status; }
+
+        private:
+            const ReplicaSetConfig _rsConfig;
+            const long long _candidateId;
+            const long long _term;
+            const OpTime _lastOplogEntry;
+            std::vector<HostAndPort> _targets;
+            bool _failed = false;
+            long long _responsesProcessed = 0;
+            long long _votes = 1;
+            Status _status = Status::OK();
+        };
+
+        VoteRequester();
+        virtual ~VoteRequester();
+
+        /**
+         * Begins the process of sending replSetRequestVotes commands to all non-DOWN nodes
+         * in currentConfig, in attempt to receive sufficient votes to win the election.
+         *
+         * evh can be used to schedule a callback when the process is complete.
+         * This function must be run in the executor, as it must be synchronous with the command
+         * callbacks that it schedules.
+         * If this function returns Status::OK(), evh is then guaranteed to be signaled.
+         **/
+        StatusWith<ReplicationExecutor::EventHandle> start(
+            ReplicationExecutor* executor,
+            const ReplicaSetConfig& rsConfig,
+            long long candidateId,
+            long long term,
+            OpTime lastOplogEntry,
+            const stdx::function<void ()>& onCompletion = stdx::function<void ()>());
+
+        /**
+         * Informs the VoteRequester to cancel further processing.  The "executor"
+         * argument must point to the same executor passed to "start()".
+         *
+         * Like start(), this method must run in the executor context.
+         */
+        void cancel(ReplicationExecutor* executor);
+
+    private:
+        std::unique_ptr<Algorithm> _algorithm;
+        std::unique_ptr<ScatterGatherRunner> _runner;
+        bool _isCanceled = false;
+    };
+
+}  // namespace repl
+}  // namespace mongo
diff --git a/src/mongo/db/repl/vote_requester_test.cpp b/src/mongo/db/repl/vote_requester_test.cpp
new file mode 100644
index 00000000000..5a36015f8c6
--- /dev/null
+++ b/src/mongo/db/repl/vote_requester_test.cpp
@@ -0,0 +1,270 @@
+/**
+ *    Copyright (C) 2015 MongoDB Inc.
+ *
+ *    This program is free software: you can redistribute it and/or  modify
+ *    it under the terms of the GNU Affero General Public License, version 3,
+ *    as published by the Free Software Foundation.
+ *
+ *    This program is distributed in the hope that it will be useful,
+ *    but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *    GNU Affero General Public License for more details.
+ *
+ *    You should have received a copy of the GNU Affero General Public License
+ *    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ *    As a special exception, the copyright holders give permission to link the
+ *    code of portions of this program with the OpenSSL library under certain
+ *    conditions as described in each individual source file and distribute
+ *    linked combinations including the program with the OpenSSL library. You
+ *    must comply with the GNU Affero General Public License in all respects for
+ *    all of the code used other than as permitted herein. If you modify file(s)
+ *    with this exception, you may extend this exception to your version of the
+ *    file(s), but you are not obligated to do so. If you do not wish to do so,
+ *    delete this exception statement from your version. If you delete this
+ *    exception statement from all source files in the program, then also delete
+ *    it in the license file.
+ */
+
+#include "mongo/platform/basic.h"
+
+#include <memory>
+
+#include "mongo/base/status.h"
+#include "mongo/db/jsobj.h"
+#include "mongo/db/repl/vote_requester.h"
+#include "mongo/db/repl/network_interface_mock.h"
+#include "mongo/db/repl/repl_set_request_votes_args.h"
+#include "mongo/db/repl/replication_executor.h"
+#include "mongo/stdx/functional.h"
+#include "mongo/unittest/unittest.h"
+#include "mongo/util/mongoutils/str.h"
+
+namespace mongo {
+namespace repl {
+namespace {
+    using unittest::assertGet;
+
+    using RemoteCommandRequest = ReplicationExecutor::RemoteCommandRequest;
+
+    bool stringContains(const std::string &haystack, const std::string& needle) {
+        return haystack.find(needle) != std::string::npos;
+    }
+
+
+    class VoteRequesterTest : public mongo::unittest::Test {
+    public:
+        virtual void setUp() {
+            ReplicaSetConfig config;
+            ASSERT_OK(config.initialize(
+                BSON("_id" << "rs0" <<
+                     "version" << 2 <<
+                     "members" << BSON_ARRAY(
+                         BSON("_id" << 0 << "host" << "host0") <<
+                         BSON("_id" << 1 << "host" << "host1") <<
+                         BSON("_id" << 2 << "host" << "host2") <<
+                         BSON("_id" << 3 << "host" << "host3" << "votes" << 0) <<
+                         BSON("_id" << 4 << "host" << "host4" << "votes" << 0)))));
+            ASSERT_OK(config.validate());
+            long long candidateId = 0;
+            long long term = 2;
+            OpTime lastOplogEntry = OpTime(Timestamp(999,0), 1);
+
+            _requester.reset(new VoteRequester::Algorithm(config,
+                                                          candidateId,
+                                                          term,
+                                                          lastOplogEntry));
+        }
+
+        virtual void tearDown() {
+            _requester.reset(NULL);
+        }
+
+    protected:
+        int64_t countLogLinesContaining(const std::string& needle) {
+            return std::count_if(getCapturedLogMessages().begin(),
+                                 getCapturedLogMessages().end(),
+                                 stdx::bind(stringContains,
+                                            stdx::placeholders::_1,
+                                            needle));
+        }
+
+        bool hasReceivedSufficientResponses() {
+            return _requester->hasReceivedSufficientResponses();
+        }
+
+        void processResponse(const RemoteCommandRequest& request, const ResponseStatus& response) {
+            _requester->processResponse(request, response);
+        }
+
+        Status getStatus() {
+            return _requester->getStatus();
+        }
+
+        RemoteCommandRequest requestFrom(std::string hostname) {
+            return RemoteCommandRequest(HostAndPort(hostname),
+                                        "", // fields do not matter in VoteRequester
+                                        BSONObj(),
+                                        Milliseconds(0));
+        }
+
+        ResponseStatus badResponseStatus() {
+            return ResponseStatus(ErrorCodes::NodeNotFound, "not on my watch");
+        }
+
+        ResponseStatus votedYes() {
+            ReplSetRequestVotesResponse response;
+            response.setOk(true);
+            response.setVoteGranted(true);
+            response.setTerm(1);
+            return ResponseStatus(NetworkInterfaceMock::Response(response.toBSON(),
+                                                                 Milliseconds(10)));
+        }
+
+        ResponseStatus votedNoBecauseConfigVersionDoesNotMatch() {
+            ReplSetRequestVotesResponse response;
+            response.setOk(true);
+            response.setVoteGranted(false);
+            response.setTerm(1);
+            response.setReason("candidate's config version differs from mine");
+            return ResponseStatus(NetworkInterfaceMock::Response(response.toBSON(),
+                                                                 Milliseconds(10)));
+        }
+
+        ResponseStatus votedNoBecauseSetNameDiffers() {
+            ReplSetRequestVotesResponse response;
+            response.setOk(true);
+            response.setVoteGranted(false);
+            response.setTerm(1);
+            response.setReason("candidate's set name differs from mine");
+            return ResponseStatus(NetworkInterfaceMock::Response(response.toBSON(),
+                                                                 Milliseconds(10)));
+        }
+
+        ResponseStatus votedNoBecauseLastOpTimeIsGreater() {
+            ReplSetRequestVotesResponse response;
+            response.setOk(true);
+            response.setVoteGranted(false);
+            response.setTerm(1);
+            response.setReason("candidate's data is staler than mine");
+            return ResponseStatus(NetworkInterfaceMock::Response(response.toBSON(),
+                                                                 Milliseconds(10)));
+        }
+
+        ResponseStatus votedNoBecauseTermIsGreater() {
+            ReplSetRequestVotesResponse response;
+            response.setOk(true);
+            response.setVoteGranted(false);
+            response.setTerm(3);
+            response.setReason("candidate's term is lower than mine");
+            return ResponseStatus(NetworkInterfaceMock::Response(response.toBSON(),
+                                                                 Milliseconds(10)));
+        }
+
+        ResponseStatus votedNoBecauseAlreadyVoted() {
+            ReplSetRequestVotesResponse response;
+            response.setOk(true);
+            response.setVoteGranted(false);
+            response.setTerm(2);
+            response.setReason("already voted for another candidate this term");
+            return ResponseStatus(NetworkInterfaceMock::Response(response.toBSON(),
+                                                                 Milliseconds(10)));
+        }
+
+    private:
+        std::unique_ptr<VoteRequester::Algorithm> _requester;
+    };
+
+    TEST_F(VoteRequesterTest, ImmediateGoodResponseWinElection) {
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        processResponse(requestFrom("host1"), votedYes());
+        ASSERT_TRUE(hasReceivedSufficientResponses());
+        ASSERT_OK(getStatus());
+    }
+
+    TEST_F(VoteRequesterTest, BadConfigVersionWinElection) {
+        startCapturingLogMessages();
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        processResponse(requestFrom("host1"), votedNoBecauseConfigVersionDoesNotMatch());
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        ASSERT_EQUALS(1, countLogLinesContaining("Got no vote from host1"));
+        processResponse(requestFrom("host2"), votedYes());
+        ASSERT_TRUE(hasReceivedSufficientResponses());
+        ASSERT_OK(getStatus());
+        stopCapturingLogMessages();
+    }
+
+    TEST_F(VoteRequesterTest, SetNameDiffersWinElection) {
+        startCapturingLogMessages();
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        processResponse(requestFrom("host1"), votedNoBecauseSetNameDiffers());
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        ASSERT_EQUALS(1, countLogLinesContaining("Got no vote from host1"));
+        processResponse(requestFrom("host2"), votedYes());
+        ASSERT_TRUE(hasReceivedSufficientResponses());
+        ASSERT_OK(getStatus());
+        stopCapturingLogMessages();
+    }
+
+    TEST_F(VoteRequesterTest, LastOpTimeIsGreaterWinElection) {
+        startCapturingLogMessages();
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        processResponse(requestFrom("host1"), votedNoBecauseLastOpTimeIsGreater());
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        ASSERT_EQUALS(1, countLogLinesContaining("Got no vote from host1"));
+        processResponse(requestFrom("host2"), votedYes());
+        ASSERT_TRUE(hasReceivedSufficientResponses());
+        ASSERT_OK(getStatus());
+        stopCapturingLogMessages();
+    }
+
+    TEST_F(VoteRequesterTest, FailedToContactWinElection) {
+        startCapturingLogMessages();
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        processResponse(requestFrom("host1"), badResponseStatus());
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        ASSERT_EQUALS(1, countLogLinesContaining("Got failed response from host1"));
+        processResponse(requestFrom("host2"), votedYes());
+        ASSERT_TRUE(hasReceivedSufficientResponses());
+        ASSERT_OK(getStatus());
+        stopCapturingLogMessages();
+    }
+
+    TEST_F(VoteRequesterTest, AlreadyVotedWinElection) {
+        startCapturingLogMessages();
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        processResponse(requestFrom("host1"), votedNoBecauseAlreadyVoted());
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        ASSERT_EQUALS(1, countLogLinesContaining("Got no vote from host1"));
+        processResponse(requestFrom("host2"), votedYes());
+        ASSERT_TRUE(hasReceivedSufficientResponses());
+        ASSERT_OK(getStatus());
+        stopCapturingLogMessages();
+    }
+
+    TEST_F(VoteRequesterTest, StaleTermLoseElection) {
+        startCapturingLogMessages();
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        processResponse(requestFrom("host1"), votedNoBecauseTermIsGreater());
+        ASSERT_EQUALS(1, countLogLinesContaining("Got no vote from host1"));
+        ASSERT_TRUE(hasReceivedSufficientResponses());
+        ASSERT_EQUALS(getStatus().reason(), "running for a stale term");
+        stopCapturingLogMessages();
+    }
+
+    TEST_F(VoteRequesterTest, NotEnoughVotesLoseElection) {
+        startCapturingLogMessages();
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        processResponse(requestFrom("host1"), votedNoBecauseSetNameDiffers());
+        ASSERT_FALSE(hasReceivedSufficientResponses());
+        ASSERT_EQUALS(1, countLogLinesContaining("Got no vote from host1"));
+        processResponse(requestFrom("host2"), badResponseStatus());
+        ASSERT_EQUALS(1, countLogLinesContaining("Got failed response from host2"));
+        ASSERT_TRUE(hasReceivedSufficientResponses());
+        ASSERT_EQUALS(getStatus().reason(), "received insufficient votes");
+        stopCapturingLogMessages();
+    }
+
+}  // namespace
+}  // namespace repl
+}  // namespace mongo