SERVER-114059 Update quorum checking to use the maintenance port (#44097)

GitOrigin-RevId: cf17bc5c326a07822e72cce4b5ce1d3cc828fab9

jstests/noPassthrough/replication/maintenance_port_reconfig.js

@@ -9,6 +9,7 @@ import {ReplSetTest} from "jstests/libs/replsettest.js";
 import {afterEach, beforeEach, describe, it} from "jstests/libs/mochalite.js";
 import {FeatureFlagUtil} from "jstests/libs/feature_flag_util.js";
 import {get_ipaddr} from "jstests/libs/host_ipaddr.js";
+import {configureFailPointForRS} from "jstests/libs/fail_point_util.js";
 
 describe("Tests for maintenance port usage within JS test helpers", function () {
     beforeEach(() => {
@@ -20,6 +21,14 @@ describe("Tests for maintenance port usage within JS test helpers", function ()
             ).version;
             return MongoRunner.compareBinVersions(lastLTSFCV, maintenancePortEnabledFCV) == -1;
         };
+
+        this.dropAllConns = function (rs) {
+            rs.nodes.forEach((conn) => {
+                const cfg = conn.getDB("local").system.replset.findOne();
+                const allHosts = cfg.members.map((x) => x.host);
+                assert.commandWorked(conn.adminCommand({dropConnections: 1, hostAndPort: allHosts}));
+            });
+        };
     });
 
     it("ReplSetInitiate with maintenance port on FCV 8.0 will fail", () => {
@@ -120,6 +129,73 @@ describe("Tests for maintenance port usage within JS test helpers", function ()
         rs.stopSet();
     });
 
+    it("Initiate with wrong maintenance port on a majority of nodes should fail", () => {
+        const rs = new ReplSetTest({nodes: [{maintenancePort: allocatePort()}, {}, {}]});
+        rs.startSet();
+
+        jsTest.log.info(
+            "Initiate should fail because we specify maintenance ports which are not open on the secondaries",
+        );
+        let config = rs.getReplSetConfig();
+        config.members[1].maintenancePort = 27022;
+        config.members[2].maintenancePort = 27023;
+
+        assert.commandFailedWithCode(rs.nodes[0].adminCommand({replSetInitiate: config}), ErrorCodes.NodeNotFound);
+
+        rs.stopSet();
+    });
+
+    it("Reconfig with wrong maintenance port on a majority of nodes should fail", () => {
+        const rs = new ReplSetTest({nodes: [{maintenancePort: allocatePort()}, {}, {}]});
+        rs.startSet();
+        rs.initiate();
+
+        jsTest.log.info(
+            "Initiate should fail because we specify maintenance ports which are not open on the secondaries",
+        );
+        let config = rs.getReplSetConfigFromNode();
+        config.members[1].maintenancePort = 27022;
+        config.members[2].maintenancePort = 27023;
+        config.version += 1;
+
+        assert.commandFailedWithCode(rs.getPrimary().adminCommand({replSetReconfig: config}), ErrorCodes.NodeNotFound);
+
+        rs.stopSet();
+    });
+
+    it("Initiate when we can only reach the maintenance port on a majority of nodes should fail", () => {
+        const rs = new ReplSetTest({nodes: 3, useMaintenancePorts: true});
+        rs.startSet();
+
+        jsTest.log.info("Block connections on the main ports");
+        let fps = configureFailPointForRS(rs.nodes, "rejectNewNonPriorityConnections");
+
+        jsTest.log.info("Initiate should fail because we can only connect on the maintenance ports");
+        let config = rs.getReplSetConfig();
+        assert.commandFailedWithCode(rs.nodes[0].adminCommand({replSetInitiate: config}), ErrorCodes.NodeNotFound);
+
+        rs.stopSet();
+    });
+
+    it("Reconfig when we can only reach the maintenance port on a majority of nodes should fail", () => {
+        const rs = new ReplSetTest({nodes: 3, useMaintenancePorts: true});
+        rs.startSet();
+        rs.initiate();
+
+        let config = rs.getReplSetConfigFromNode();
+
+        jsTest.log.info("Block connections on the main ports and drop existing connections");
+        let fps = configureFailPointForRS(rs.nodes, "rejectNewNonPriorityConnections");
+        this.dropAllConns(rs);
+
+        jsTest.log.info("Reconfig should fail because we can only connect on the maintenance ports");
+        config.version += 1;
+        assert.commandFailedWithCode(rs.getPrimary().adminCommand({replSetReconfig: config}), ErrorCodes.NodeNotFound);
+
+        fps.off();
+        rs.stopSet();
+    });
+
     it("Initiate with maintenance port plus bindIp works when fast resolution works", () => {
         let ips = "localhost," + get_ipaddr();
         const rs = new ReplSetTest({

src/mongo/db/repl/check_quorum_for_config_change.cpp

@@ -65,15 +65,23 @@ QuorumChecker::QuorumChecker(const ReplSetConfig* rsConfig, int myIndex, long lo
     : _rsConfig(rsConfig),
       _myIndex(myIndex),
       _term(term),
+      _responses(_rsConfig->getNumMembers(), {false, false, false}),
+      _successfulVoterCount(0),
       _numResponses(1),  // We "responded" to ourself already.
       _numElectable(0),
+      _numResponsesRequired(_rsConfig->getNumMembers() +
+                            _rsConfig->getCountOfMembersWithMaintenancePort()),
       _vetoStatus(Status::OK()),
       _finalStatus(ErrorCodes::CallbackCanceled, "Quorum check canceled") {
     invariant(myIndex < _rsConfig->getNumMembers());
     const MemberConfig& myConfig = _rsConfig->getMemberAt(_myIndex);
 
+    _responses.at(myIndex) = {true, myConfig.getMaintenancePort().is_initialized(), true};
     if (myConfig.isVoter()) {
-        _voters.push_back(myConfig.getHostAndPort());
+        _successfulVoterCount++;
+    }
+    if (myConfig.getMaintenancePort()) {
+        _numResponses++;
     }
     if (myConfig.isElectable()) {
         _numElectable = 1;
@@ -107,7 +115,9 @@ std::vector<RemoteCommandRequest> QuorumChecker::getRequests() const {
     }
     // hbArgs allows (but doesn't require) us to pass the current primary id as an optimization,
     // but it is not readily available within QuorumChecker.
-    hbArgs.setSenderHost(myConfig.getHostAndPort());
+    // Use the maintenance port because the recipient may send a heartbeat back to get a newer
+    // configuration and we want them to use the maintenance port if it is available.
+    hbArgs.setSenderHost(myConfig.getHostAndPortMaintenance());
     hbArgs.setSenderId(myConfig.getId().getData());
     hbArgs.setTerm(_term);
     hbRequest = hbArgs.toBSON();
@@ -121,12 +131,24 @@ std::vector<RemoteCommandRequest> QuorumChecker::getRequests() const {
             // No need to check self for liveness or unreadiness.
             continue;
         }
-        requests.push_back(RemoteCommandRequest(_rsConfig->getMemberAt(i).getHostAndPort(),
+        const auto& member = _rsConfig->getMemberAt(i);
+        requests.push_back(RemoteCommandRequest(member.getHostAndPort(),
                                                 DatabaseName::kAdmin,
                                                 hbRequest,
                                                 BSON(rpc::kReplSetMetadataFieldName << 1),
                                                 nullptr,
                                                 _rsConfig->getHeartbeatTimeoutPeriodMillis()));
+
+        // If a member has a maintenance port specified then we need to check connectivity to both
+        // the main and the maintenance ports.
+        if (member.getMaintenancePort()) {
+            requests.push_back(RemoteCommandRequest(member.getHostAndPortMaintenance(),
+                                                    DatabaseName::kAdmin,
+                                                    hbRequest,
+                                                    BSON(rpc::kReplSetMetadataFieldName << 1),
+                                                    nullptr,
+                                                    _rsConfig->getHeartbeatTimeoutPeriodMillis()));
+        }
     }
 
     return requests;
@@ -140,6 +162,38 @@ void QuorumChecker::processResponse(const RemoteCommandRequest& request,
     }
 }
 
+void QuorumChecker::_appendFailedHeartbeatResponses(str::stream& stream) {
+    for (std::vector<std::pair<HostAndPort, Status>>::const_iterator it = _badResponses.begin();
+         it != _badResponses.end();
+         ++it) {
+        if (it != _badResponses.begin()) {
+            stream << ", ";
+        }
+        stream << it->first.toString() << " failed with " << it->second.reason();
+    }
+}
+
+void QuorumChecker::_appendFullySuccessfulVotingHostAndPorts(str::stream& stream,
+                                                             int expectedResponses) {
+    int count = 0;
+    for (int i = 0; i < _rsConfig->getNumMembers(); ++i) {
+        if (!_responses.at(i).fullySuccessful) {
+            continue;
+        }
+        const auto& member = _rsConfig->getMemberAt(i);
+        if (!member.isVoter()) {
+            continue;
+        }
+        if (count != 0) {
+            stream << ", ";
+        }
+        stream << member.getHostAndPort().toString();
+        if (++count == expectedResponses) {
+            break;
+        }
+    }
+}
+
 void QuorumChecker::_onQuorumCheckComplete() {
     if (!_vetoStatus.isOK()) {
         _finalStatus = _vetoStatus;
@@ -149,14 +203,7 @@ void QuorumChecker::_onQuorumCheckComplete() {
         str::stream message;
         message << "replSetInitiate quorum check failed because not all proposed set members "
                    "responded affirmatively: ";
-        for (std::vector<std::pair<HostAndPort, Status>>::const_iterator it = _badResponses.begin();
+        _appendFailedHeartbeatResponses(message);
-             it != _badResponses.end();
-             ++it) {
-            if (it != _badResponses.begin()) {
-                message << ", ";
-            }
-            message << it->first.toString() << " failed with " << it->second.reason();
-        }
         _finalStatus = Status(ErrorCodes::NodeNotFound, message);
         return;
     }
@@ -166,31 +213,21 @@ void QuorumChecker::_onQuorumCheckComplete() {
                               "electable nodes responded; at least one required for config");
         return;
     }
-    if (int(_voters.size()) < _rsConfig->getMajorityVoteCount()) {
+    if (_successfulVoterCount < _rsConfig->getMajorityVoteCount()) {
         str::stream message;
         message << "Quorum check failed because not enough voting nodes responded; required "
                 << _rsConfig->getMajorityVoteCount() << " but ";
 
-        if (_voters.size() == 0) {
+        if (_successfulVoterCount == 0) {
             message << "none responded";
         } else {
-            message << "only the following " << _voters.size()
+            message << "only the following " << _successfulVoterCount
-                    << " voting nodes responded: " << _voters.front().toString();
+                    << " voting nodes responded: ";
-            for (size_t i = 1; i < _voters.size(); ++i) {
+            _appendFullySuccessfulVotingHostAndPorts(message, _successfulVoterCount);
-                message << ", " << _voters[i].toString();
-            }
         }
         if (!_badResponses.empty()) {
             message << "; the following nodes did not respond affirmatively: ";
-            for (std::vector<std::pair<HostAndPort, Status>>::const_iterator it =
+            _appendFailedHeartbeatResponses(message);
-                     _badResponses.begin();
-                 it != _badResponses.end();
-                 ++it) {
-                if (it != _badResponses.begin()) {
-                    message << ", ";
-                }
-                message << it->first.toString() << " failed with " << it->second.reason();
-            }
         }
         _finalStatus = Status(ErrorCodes::NodeNotFound, message);
         return;
@@ -257,14 +294,27 @@ void QuorumChecker::_tabulateHeartbeatResponse(const RemoteCommandRequest& reque
 
     for (int i = 0; i < _rsConfig->getNumMembers(); ++i) {
         const MemberConfig& memberConfig = _rsConfig->getMemberAt(i);
-        if (memberConfig.getHostAndPort() != request.target) {
+        if (memberConfig.getHostAndPort() != request.target &&
+            memberConfig.getHostAndPortMaintenance() != request.target) {
             continue;
         }
-        if (memberConfig.isElectable()) {
+        if (memberConfig.getMaintenancePort() &&
-            ++_numElectable;
+            memberConfig.getHostAndPortMaintenance() == request.target) {
+            _responses.at(i).maintenanceResponseReceived = true;
+        } else {
+            _responses.at(i).mainResponseReceived = true;
         }
-        if (memberConfig.isVoter()) {
+        // Check if we have now received both responses for this node.
-            _voters.push_back(request.target);
+        _responses.at(i).fullySuccessful = _responses.at(i).mainResponseReceived &&
+            (!memberConfig.getMaintenancePort() || _responses.at(i).maintenanceResponseReceived);
+        // If we have received both responses for this node then update our global counters.
+        if (_responses.at(i).fullySuccessful) {
+            if (memberConfig.isVoter()) {
+                ++_successfulVoterCount;
+            }
+            if (memberConfig.isElectable()) {
+                ++_numElectable;
+            }
         }
         return;
     }
@@ -272,7 +322,7 @@ void QuorumChecker::_tabulateHeartbeatResponse(const RemoteCommandRequest& reque
 }
 
 bool QuorumChecker::hasReceivedSufficientResponses() const {
-    if (!_vetoStatus.isOK() || _numResponses == _rsConfig->getNumMembers()) {
+    if (!_vetoStatus.isOK() || _numResponses == _numResponsesRequired) {
         // Vetoed or everybody has responded.  All done.
         return true;
     }

src/mongo/db/repl/check_quorum_for_config_change.h

@@ -94,6 +94,22 @@ private:
     void _tabulateHeartbeatResponse(const executor::RemoteCommandRequest& request,
                                     const executor::RemoteCommandResponse& response);
 
+    /**
+     * Adds information about each failed heartbeat response to the provided stream with the format:
+     * "<host:port> failed with <errmsg>, <host:port> failed with <errmsg>".
+     */
+    void _appendFailedHeartbeatResponses(str::stream& stream);
+
+    /**
+     * Adds information about each fully successful voting node to the provided stream with the
+     * format:
+     * "<host:port>, <host:port>"
+     * A fully successful voting node is one which replied success over its main port and either
+     * does not have a maintenance port configured or also replied success over the maintenance
+     * port.
+     */
+    void _appendFullySuccessfulVotingHostAndPorts(str::stream& stream, int expectedResponses);
+
     // Pointer to the replica set configuration for which we're checking quorum.
     const ReplSetConfig* const _rsConfig;
 
@@ -103,8 +119,18 @@ private:
     // The term of this node.
     const long long _term;
 
-    // List of voting nodes that have responded affirmatively.
+    struct ResponseStatus {
-    std::vector<HostAndPort> _voters;
+        bool mainResponseReceived;
+        bool maintenanceResponseReceived;
+        bool fullySuccessful;
+    };
+    // Tracks main and maintenance port responses for each member. The indexes into this vector will
+    // be the same as that of the _rsConfig and entries for non-voters will be all false.
+    std::vector<ResponseStatus> _responses;
+    // Tracks the number of voters for which their state is fully successful (meaning they have
+    // responded on the main port and do not have a maintenance port configured or have responded
+    // on both main and maintenance ports).
+    int _successfulVoterCount;
 
     // List of nodes with bad responses and the bad response status they returned.
     std::vector<std::pair<HostAndPort, Status>> _badResponses;
@@ -112,9 +138,15 @@ private:
     // Total number of responses and timeouts processed.
     int _numResponses;
 
-    // Number of electable nodes that have responded affirmatively.
+    // Number of electable nodes that have responded affirmatively (on both their main and
+    // maintenance ports).
     int _numElectable;
 
+    // Number of responses required. This will be equal to the number of members in the config plus
+    // the number of members that have maintenance ports specified since we need to contact both
+    // ports in that case.
+    int _numResponsesRequired;
+
     // Set to a non-OK status if a response from a remote node indicates
     // that the quorum check should definitely fail, such as because of
     // a replica set name mismatch.

src/mongo/db/repl/check_quorum_for_config_change_test.cpp

@@ -232,7 +232,7 @@ BSONObj makeHeartbeatRequest(const ReplSetConfig& rsConfig, int myConfigIndex) {
     if (rsConfig.getConfigVersion() == 1) {
         hbArgs.setCheckEmpty();
     }
-    hbArgs.setSenderHost(myConfig.getHostAndPort());
+    hbArgs.setSenderHost(myConfig.getHostAndPortMaintenance());
     hbArgs.setSenderId(myConfig.getId().getData());
     hbArgs.setTerm(0);
     return hbArgs.toBSON();
@@ -500,6 +500,65 @@ TEST_F(CheckQuorumForInitiate, QuorumCheckFailedDueToSetIdMismatch) {
     ASSERT_NOT_REASON_CONTAINS(status, "h5:1");
 }
 
+TEST_F(CheckQuorumForInitiate, QuorumCheckFailedDueToMaintenancePortUnreachable) {
+    // In this test, "we" are host "h1:1".  All nodes respond successfully to their heartbeat
+    // requests on the main port but "we" don't respond via our maintenance port.
+
+    const ReplSetConfig rsConfig = assertMakeRSConfig(
+        BSON("_id" << "rs0"
+                   << "version" << 1 << "protocolVersion" << 1 << "members"
+                   << BSON_ARRAY(BSON("_id" << 1 << "host"
+                                            << "h1:1")
+                                 << BSON("_id" << 2 << "host"
+                                               << "h2:1")
+                                 << BSON("_id" << 3 << "host"
+                                               << "h3:1" << "maintenancePort" << 2)
+                                 << BSON("_id" << 4 << "host"
+                                               << "h4:1")
+                                 << BSON("_id" << 5 << "host"
+                                               << "h5:1"))));
+    const int myConfigIndex = 0;
+    const BSONObj hbRequest = makeHeartbeatRequest(rsConfig, myConfigIndex);
+
+    startQuorumCheck(rsConfig, myConfigIndex);
+    const Date_t startDate = getNet()->now();
+    const int numCommandsExpected =
+        rsConfig.getNumMembers();  // One more than normal because one maintenance port.
+    stdx::unordered_set<HostAndPort> seenHosts;
+    getNet()->enterNetwork();
+    for (int i = 0; i < numCommandsExpected; ++i) {
+        const NetworkInterfaceMock::NetworkOperationIterator noi = getNet()->getNextReadyRequest();
+        const RemoteCommandRequest& request = noi->getRequest();
+        ASSERT_EQUALS(DatabaseName::kAdmin, request.dbname);
+        ASSERT_BSONOBJ_EQ(hbRequest, request.cmdObj);
+        ASSERT(seenHosts.insert(request.target).second)
+            << "Already saw " << request.target.toString();
+        if (request.target == HostAndPort("h3", 2)) {
+            getNet()->scheduleResponse(noi,
+                                       startDate + Milliseconds(10),
+                                       RemoteCommandResponse::make_forTest(
+                                           Status(ErrorCodes::HostUnreachable, "No response")));
+        } else {
+            getNet()->scheduleResponse(noi,
+                                       startDate + Milliseconds(10),
+                                       makeHeartbeatResponse(rsConfig, Milliseconds(8)));
+        }
+    }
+    getNet()->runUntil(startDate + Milliseconds(10));
+    getNet()->exitNetwork();
+    Status status = waitForQuorumCheck();
+    ASSERT_EQUALS(ErrorCodes::NodeNotFound, status);
+    ASSERT_REASON_CONTAINS(
+        status, "replSetInitiate quorum check failed because not all proposed set members");
+    ASSERT_NOT_REASON_CONTAINS(status, "h1:1");
+    ASSERT_NOT_REASON_CONTAINS(status, "h2:1");
+    ASSERT_REASON_CONTAINS(status, "h3:2");
+    ASSERT_NOT_REASON_CONTAINS(status, "h3:1");
+    ASSERT_NOT_REASON_CONTAINS(status, "h4:1");
+    ASSERT_NOT_REASON_CONTAINS(status, "h5:1");
+    ASSERT_NOT_REASON_CONTAINS(status, "h6:1");
+}
+
 TEST_F(CheckQuorumForReconfig, QuorumCheckSucceedsWhenOtherNodesHaveHigherVersion) {
     // In this test, "we" are host "h3:1".  The request to "h2" does not arrive before the end
     // of the test, and the request to "h1" comes back indicating a higher config version.
@@ -661,6 +720,187 @@ TEST_F(CheckQuorumForReconfig, QuorumCheckFailsDueToInsufficientVoters) {
     ASSERT_NOT_REASON_CONTAINS(status, "h5:1");
 }
 
+TEST_F(CheckQuorumForReconfig, QuorumCheckFailsDueToInsufficientMaintenancePortResponses) {
+    // In this test, "we" are host "h4".  All nodes respond via their main port but only "h1"
+    // responds via its maintenance port.
+
+    const ReplSetConfig rsConfig = assertMakeRSConfig(BSON(
+        "_id" << "rs0"
+              << "version" << 2 << "protocolVersion" << 1 << "members"
+              << BSON_ARRAY(
+                     BSON("_id" << 1 << "host"
+                                << "h1:1" << "maintenancePort" << 2)
+                     << BSON("_id" << 2 << "host"
+                                   << "h2:1" << "maintenancePort" << 2)
+                     << BSON("_id" << 3 << "host"
+                                   << "h3:1" << "maintenancePort" << 2)
+                     << BSON("_id" << 4 << "host"
+                                   << "h4:1"
+                                   << "votes" << 0 << "priority" << 0 << "maintenancePort" << 2)
+                     << BSON("_id" << 5 << "host"
+                                   << "h5:1"
+                                   << "votes" << 0 << "priority" << 0 << "maintenancePort" << 2))));
+    const int myConfigIndex = 3;
+    const BSONObj hbRequest = makeHeartbeatRequest(rsConfig, myConfigIndex);
+
+    std::set<HostAndPort> respondFailure = {HostAndPort("h2", 2), HostAndPort("h3", 2)};
+
+    startQuorumCheck(rsConfig, myConfigIndex);
+    const Date_t startDate = getNet()->now();
+    const int numCommandsExpected = (rsConfig.getNumMembers() * 2) - 2;
+    stdx::unordered_set<HostAndPort> seenHosts;
+    getNet()->enterNetwork();
+    for (int i = 0; i < numCommandsExpected; ++i) {
+        const NetworkInterfaceMock::NetworkOperationIterator noi = getNet()->getNextReadyRequest();
+        const RemoteCommandRequest& request = noi->getRequest();
+        ASSERT_EQUALS(DatabaseName::kAdmin, request.dbname);
+        ASSERT_BSONOBJ_EQ(hbRequest, request.cmdObj);
+        ASSERT(seenHosts.insert(request.target).second)
+            << "Already saw " << request.target.toString();
+        if (respondFailure.contains(request.target)) {
+            getNet()->scheduleResponse(noi,
+                                       startDate + Milliseconds(10),
+                                       RemoteCommandResponse::make_forTest(
+                                           Status(ErrorCodes::HostUnreachable, "No response")));
+        } else {
+            getNet()->scheduleResponse(noi,
+                                       startDate + Milliseconds(10),
+                                       makeHeartbeatResponse(rsConfig, Milliseconds(8)));
+        }
+    }
+    getNet()->runUntil(startDate + Milliseconds(10));
+    getNet()->exitNetwork();
+    Status status = waitForQuorumCheck();
+    ASSERT_EQUALS(ErrorCodes::NodeNotFound, status);
+    ASSERT_REASON_CONTAINS(status, "not enough voting nodes responded; required 2 but only");
+    ASSERT_REASON_CONTAINS(status, "h1:1");
+    ASSERT_REASON_CONTAINS(status, "h2:2 failed with");
+    ASSERT_REASON_CONTAINS(status, "h3:2 failed with");
+    ASSERT_NOT_REASON_CONTAINS(status, "h4:1");
+    ASSERT_NOT_REASON_CONTAINS(status, "h5:1");
+}
+
+TEST_F(CheckQuorumForReconfig, QuorumCheckFailsDueToInsufficientMainPortResponses) {
+    // In this test, "we" are host "h4".  All nodes respond via their maintenance port but only "h1"
+    // responds via its main port.
+
+    const ReplSetConfig rsConfig = assertMakeRSConfig(BSON(
+        "_id" << "rs0"
+              << "version" << 2 << "protocolVersion" << 1 << "members"
+              << BSON_ARRAY(
+                     BSON("_id" << 1 << "host"
+                                << "h1:1" << "maintenancePort" << 2)
+                     << BSON("_id" << 2 << "host"
+                                   << "h2:1" << "maintenancePort" << 2)
+                     << BSON("_id" << 3 << "host"
+                                   << "h3:1" << "maintenancePort" << 2)
+                     << BSON("_id" << 4 << "host"
+                                   << "h4:1"
+                                   << "votes" << 0 << "priority" << 0 << "maintenancePort" << 2)
+                     << BSON("_id" << 5 << "host"
+                                   << "h5:1"
+                                   << "votes" << 0 << "priority" << 0 << "maintenancePort" << 2))));
+    const int myConfigIndex = 3;
+    const BSONObj hbRequest = makeHeartbeatRequest(rsConfig, myConfigIndex);
+
+    std::set<HostAndPort> respondFailure = {HostAndPort("h2", 1), HostAndPort("h3", 1)};
+
+    startQuorumCheck(rsConfig, myConfigIndex);
+    const Date_t startDate = getNet()->now();
+    const int numCommandsExpected = (rsConfig.getNumMembers() * 2) - 2;
+    stdx::unordered_set<HostAndPort> seenHosts;
+    getNet()->enterNetwork();
+    for (int i = 0; i < numCommandsExpected; ++i) {
+        const NetworkInterfaceMock::NetworkOperationIterator noi = getNet()->getNextReadyRequest();
+        const RemoteCommandRequest& request = noi->getRequest();
+        ASSERT_EQUALS(DatabaseName::kAdmin, request.dbname);
+        ASSERT_BSONOBJ_EQ(hbRequest, request.cmdObj);
+        ASSERT(seenHosts.insert(request.target).second)
+            << "Already saw " << request.target.toString();
+        if (respondFailure.contains(request.target)) {
+            getNet()->scheduleResponse(noi,
+                                       startDate + Milliseconds(10),
+                                       RemoteCommandResponse::make_forTest(
+                                           Status(ErrorCodes::HostUnreachable, "No response")));
+        } else {
+            getNet()->scheduleResponse(noi,
+                                       startDate + Milliseconds(10),
+                                       makeHeartbeatResponse(rsConfig, Milliseconds(8)));
+        }
+    }
+    getNet()->runUntil(startDate + Milliseconds(10));
+    getNet()->exitNetwork();
+    Status status = waitForQuorumCheck();
+    ASSERT_EQUALS(ErrorCodes::NodeNotFound, status);
+    ASSERT_REASON_CONTAINS(status, "not enough voting nodes responded; required 2 but only");
+    ASSERT_REASON_CONTAINS(status, "h1:1");
+    ASSERT_REASON_CONTAINS(status, "h2:1 failed with");
+    ASSERT_REASON_CONTAINS(status, "h3:1 failed with");
+    ASSERT_NOT_REASON_CONTAINS(status, "h4:1");
+    ASSERT_NOT_REASON_CONTAINS(status, "h5:1");
+}
+
+TEST_F(CheckQuorumForReconfig, QuorumCheckFailsDueToNonOverlappingMainAndMaintenancePortResponses) {
+    // In this test, "we" are host "h3".  Nodes 1 and 2 respond via their main port but not
+    // maintenance port and hosts 4 and 5 respond via their maintenance port not main port. Thus we
+    // have no overlapping majority.
+
+    const ReplSetConfig rsConfig = assertMakeRSConfig(
+        BSON("_id" << "rs0"
+                   << "version" << 2 << "protocolVersion" << 1 << "members"
+                   << BSON_ARRAY(BSON("_id" << 1 << "host"
+                                            << "h1:1" << "maintenancePort" << 2)
+                                 << BSON("_id" << 2 << "host"
+                                               << "h2:1" << "maintenancePort" << 2)
+                                 << BSON("_id" << 3 << "host"
+                                               << "h3:1" << "maintenancePort" << 2)
+                                 << BSON("_id" << 4 << "host"
+                                               << "h4:1"
+                                               << "maintenancePort" << 2)
+                                 << BSON("_id" << 5 << "host"
+                                               << "h5:1"
+                                               << "maintenancePort" << 2))));
+    const int myConfigIndex = 2;
+    const BSONObj hbRequest = makeHeartbeatRequest(rsConfig, myConfigIndex);
+
+    std::set<HostAndPort> respondFailure = {
+        HostAndPort("h4", 1), HostAndPort("h5", 1), HostAndPort("h1", 2), HostAndPort("h2", 2)};
+
+    startQuorumCheck(rsConfig, myConfigIndex);
+    const Date_t startDate = getNet()->now();
+    const int numCommandsExpected = (rsConfig.getNumMembers() * 2) - 2;
+    stdx::unordered_set<HostAndPort> seenHosts;
+    getNet()->enterNetwork();
+    for (int i = 0; i < numCommandsExpected; ++i) {
+        const NetworkInterfaceMock::NetworkOperationIterator noi = getNet()->getNextReadyRequest();
+        const RemoteCommandRequest& request = noi->getRequest();
+        ASSERT_EQUALS(DatabaseName::kAdmin, request.dbname);
+        ASSERT_BSONOBJ_EQ(hbRequest, request.cmdObj);
+        ASSERT(seenHosts.insert(request.target).second)
+            << "Already saw " << request.target.toString();
+        if (respondFailure.contains(request.target)) {
+            getNet()->scheduleResponse(noi,
+                                       startDate + Milliseconds(10),
+                                       RemoteCommandResponse::make_forTest(
+                                           Status(ErrorCodes::HostUnreachable, "No response")));
+        } else {
+            getNet()->scheduleResponse(noi,
+                                       startDate + Milliseconds(10),
+                                       makeHeartbeatResponse(rsConfig, Milliseconds(8)));
+        }
+    }
+    getNet()->runUntil(startDate + Milliseconds(10));
+    getNet()->exitNetwork();
+    Status status = waitForQuorumCheck();
+    ASSERT_EQUALS(ErrorCodes::NodeNotFound, status);
+    ASSERT_REASON_CONTAINS(status, "not enough voting nodes responded; required 3 but only");
+    ASSERT_REASON_CONTAINS(status, "h3:1");
+    ASSERT_REASON_CONTAINS(status, "h1:2 failed with");
+    ASSERT_REASON_CONTAINS(status, "h2:2 failed with");
+    ASSERT_REASON_CONTAINS(status, "h4:1 failed with");
+    ASSERT_REASON_CONTAINS(status, "h5:1 failed with");
+}
+
 TEST_F(CheckQuorumForReconfig, QuorumCheckFailsDueToNoElectableNodeResponding) {
     // In this test, "we" are host "h4".  Only "h1", "h2" and "h3" are electable,
     // and none of them respond.
@@ -713,6 +953,61 @@ TEST_F(CheckQuorumForReconfig, QuorumCheckFailsDueToNoElectableNodeResponding) {
     ASSERT_REASON_CONTAINS(status, "no electable nodes responded");
 }
 
+TEST_F(CheckQuorumForReconfig, QuorumCheckFailsDueToNoElectableNodeRespondingViaMaintenancePort) {
+    // In this test, "we" are host "h4".  Only "h1", "h2" and "h3" are electable,
+    // and none of them respond via their maintenance ports
+
+    const ReplSetConfig rsConfig = assertMakeRSConfig(
+        BSON("_id" << "rs0"
+                   << "version" << 2 << "protocolVersion" << 1 << "members"
+                   << BSON_ARRAY(BSON("_id" << 1 << "host"
+                                            << "h1:1" << "maintenancePort" << 2)
+                                 << BSON("_id" << 2 << "host"
+                                               << "h2:1" << "maintenancePort" << 2)
+                                 << BSON("_id" << 3 << "host"
+                                               << "h3:1" << "maintenancePort" << 2)
+                                 << BSON("_id" << 4 << "host"
+                                               << "h4:1"
+                                               << "priority" << 0 << "maintenancePort" << 2)
+                                 << BSON("_id" << 5 << "host"
+                                               << "h5:1"
+                                               << "priority" << 0 << "maintenancePort" << 2))));
+    const int myConfigIndex = 3;
+    const BSONObj hbRequest = makeHeartbeatRequest(rsConfig, myConfigIndex);
+    std::set<HostAndPort> respondFailure = {
+        HostAndPort("h1", 2), HostAndPort("h2", 2), HostAndPort("h3", 2)};
+
+
+    startQuorumCheck(rsConfig, myConfigIndex);
+    const Date_t startDate = getNet()->now();
+    const int numCommandsExpected = (2 * rsConfig.getNumMembers()) - 2;
+    stdx::unordered_set<HostAndPort> seenHosts;
+    getNet()->enterNetwork();
+    for (int i = 0; i < numCommandsExpected; ++i) {
+        const NetworkInterfaceMock::NetworkOperationIterator noi = getNet()->getNextReadyRequest();
+        const RemoteCommandRequest& request = noi->getRequest();
+        ASSERT_EQUALS(DatabaseName::kAdmin, request.dbname);
+        ASSERT_BSONOBJ_EQ(hbRequest, request.cmdObj);
+        ASSERT(seenHosts.insert(request.target).second)
+            << "Already saw " << request.target.toString();
+        if (respondFailure.contains(request.target)) {
+            getNet()->scheduleResponse(noi,
+                                       startDate + Milliseconds(10),
+                                       RemoteCommandResponse::make_forTest(
+                                           Status(ErrorCodes::HostUnreachable, "No response")));
+        } else {
+            getNet()->scheduleResponse(noi,
+                                       startDate + Milliseconds(10),
+                                       makeHeartbeatResponse(rsConfig, Milliseconds(8)));
+        }
+    }
+    getNet()->runUntil(startDate + Milliseconds(10));
+    getNet()->exitNetwork();
+    Status status = waitForQuorumCheck();
+    ASSERT_EQUALS(ErrorCodes::NodeNotFound, status);
+    ASSERT_REASON_CONTAINS(status, "no electable nodes responded");
+}
+
 TEST_F(CheckQuorumForReconfig, QuorumCheckSucceedsIfMinoritySetTimesOut) {
     // In this test, "we" are host "h4".  Only "h1", "h2" and "h3" can vote.
     // The quorum check should succeed even if we do not respond to a minority number of heartbeats,

src/mongo/db/repl/member_config.h

@@ -106,6 +106,19 @@ public:
         return _splitHorizon.getHostAndPort(horizon);
     }
 
+    /**
+     * Gets the host and maintenance port if the maintenance port is specified and the host and main
+     * port if not. Always returns the value for the default horizon since this is only intended for
+     * use by internal replication systems.
+     */
+    HostAndPort getHostAndPortMaintenance() const {
+        if (getMaintenancePort()) {
+            return HostAndPort(getHostAndPort().host(), *getMaintenancePort());
+        } else {
+            return getHostAndPort();
+        }
+    }
+
     /**
      * Gets the mapping of horizon names to `HostAndPort` for this replica set member.
      */

src/mongo/db/repl/repl_set_config.cpp

@@ -203,11 +203,14 @@ Status ReplSetConfig::_initialize(bool forInitiate,
     _addInternalWriteConcernModes();
     _initializeConnectionString();
 
-    // Count how many members can vote
+    // Count how many members can vote and how many members have maintenance ports available.
     for (const MemberConfig& m : getMembers()) {
         if (m.getNumVotes() > 0) {
             ++_votingMemberCount;
         }
+        if (m.getMaintenancePort()) {
+            ++_maintenancePortCount;
+        }
     }
 
     return Status::OK();
@@ -550,7 +553,7 @@ int ReplSetConfig::findMemberIndexByHostAndPort(const HostAndPort& hap) const {
     for (std::vector<MemberConfig>::const_iterator it = getMembers().begin();
          it != getMembers().end();
          ++it) {
-        if (it->getHostAndPort() == hap) {
+        if (it->getHostAndPort() == hap || it->getHostAndPortMaintenance() == hap) {
             return x;
         }
         ++x;

src/mongo/db/repl/repl_set_config.h

@@ -342,6 +342,13 @@ public:
         return _votingMemberCount;
     };
 
+    /**
+     * Returns a count of members with a maintenance port specified in this ReplSetConfig.
+     */
+    int getCountOfMembersWithMaintenancePort() const {
+        return _maintenancePortCount;
+    };
+
     /**
      * Access a MemberConfig element by index.
      */
@@ -617,6 +624,7 @@ private:
     int _writeMajority = 0;
     int _totalVotingMembers = 0;
     int _votingMemberCount = 0;
+    int _maintenancePortCount = 0;
     ReplSetTagConfig _tagConfig;
     StringMap<ReplSetTagPattern> _customWriteConcernModes;
     ConnectionString _connectionString;

src/mongo/db/repl/repl_set_config_test.h

@@ -60,11 +60,11 @@ inline bool operator==(const MemberConfig& a, const MemberConfig& b) {
         }
     }
     return a.getId() == b.getId() && a.getHostAndPort() == b.getHostAndPort() &&
-        a.getPriority() == b.getPriority() && a.getSecondaryDelay() == b.getSecondaryDelay() &&
+        a.getMaintenancePort() == b.getMaintenancePort() && a.getPriority() == b.getPriority() &&
-        a.isVoter() == b.isVoter() && a.isArbiter() == b.isArbiter() &&
+        a.getSecondaryDelay() == b.getSecondaryDelay() && a.isVoter() == b.isVoter() &&
-        a.isNewlyAdded() == b.isNewlyAdded() && a.isHidden() == b.isHidden() &&
+        a.isArbiter() == b.isArbiter() && a.isNewlyAdded() == b.isNewlyAdded() &&
-        a.shouldBuildIndexes() == b.shouldBuildIndexes() && a.getNumTags() == b.getNumTags() &&
+        a.isHidden() == b.isHidden() && a.shouldBuildIndexes() == b.shouldBuildIndexes() &&
-        a.getHorizonMappings() == b.getHorizonMappings() &&
+        a.getNumTags() == b.getNumTags() && a.getHorizonMappings() == b.getHorizonMappings() &&
         a.getHorizonReverseHostMappings() == b.getHorizonReverseHostMappings();
 }
 

src/mongo/db/repl/topology_coordinator.cpp

@@ -1032,7 +1032,9 @@ std::pair<ReplSetHeartbeatArgsV1, Milliseconds> TopologyCoordinator::prepareHear
         if (_selfIndex >= 0) {
             const MemberConfig& me = _selfConfig();
             hbArgs.setSenderId(me.getId().getData());
-            hbArgs.setSenderHost(me.getHostAndPort());
+            // Use the maintenance port because the recipient may send a heartbeat back to get a
+            // newer configuration and we want them to use the maintenance port if it is available.
+            hbArgs.setSenderHost(me.getHostAndPortMaintenance());
         }
         hbArgs.setTerm(_term);
     } else {

src/mongo/transport/session_manager_common.cpp

@@ -56,6 +56,8 @@
 namespace mongo::transport {
 namespace {
 
+MONGO_FAIL_POINT_DEFINE(rejectNewNonPriorityConnections);
+
 thread_local decltype(ServerGlobalParams::maxIncomingConnsOverride)::Snapshot
     maxIncomingConnsOverride;
 
@@ -275,8 +277,9 @@ void SessionManagerCommon::startSession(std::shared_ptr<Session> session) {
     IngressHandshakeMetrics::get(*session).onSessionStarted(_svcCtx->getTickSource());
 
     serverGlobalParams.maxIncomingConnsOverride.refreshSnapshot(maxIncomingConnsOverride);
-    const bool isPrivilegedSession =
+    // TODO (SERVER-113219) Check and modify this if needed.
-        maxIncomingConnsOverride && session->isExemptedByCIDRList(*maxIncomingConnsOverride);
+    const bool isPrivilegedSession = session->isConnectedToMaintenancePort() ||
+        (maxIncomingConnsOverride && session->isExemptedByCIDRList(*maxIncomingConnsOverride));
     const bool verbose = !quiet();
 
     auto service = _svcCtx->getService();
@@ -287,7 +290,9 @@ void SessionManagerCommon::startSession(std::shared_ptr<Session> session) {
     std::shared_ptr<transport::SessionWorkflow> workflow;
     {
         auto sync = _sessions->sync();
-        if (sync.size() >= _maxOpenSessions && !isPrivilegedSession) {
+        if ((sync.size() >= _maxOpenSessions ||
+             MONGO_unlikely(rejectNewNonPriorityConnections.shouldFail())) &&
+            !isPrivilegedSession) {
             _sessions->incrementRejected();
             if (verbose) {
                 ClientSummary cs(client);