SERVER-41499 Track number of elections called for each reason in serverStatus

13 files changed, 478 insertions, 16 deletions

diff --git a/src/mongo/db/repl/SConscript b/src/mongo/db/repl/SConscript
index 41aa13dddd3..926f35031e2 100644
--- a/src/mongo/db/repl/SConscript
+++ b/src/mongo/db/repl/SConscript
@@ -635,6 +635,7 @@ env.Library(
         '$BUILD_DIR/mongo/rpc/metadata',
         '$BUILD_DIR/mongo/transport/transport_layer_common',
         '$BUILD_DIR/mongo/util/fail_point',
+        '$BUILD_DIR/mongo/db/repl/replication_metrics',
         'collection_cloner',
         'initial_syncer',
         'data_replicator_external_state_initial_sync',
@@ -1361,9 +1362,33 @@ env.Library(
     ],
     LIBDEPS=[
         '$BUILD_DIR/mongo/base',
-    ],
-    LIBDEPS_PRIVATE=[
-        '$BUILD_DIR/mongo/db/commands/server_status',
         '$BUILD_DIR/mongo/db/service_context',
+        '$BUILD_DIR/mongo/db/commands/server_status',
+        'topology_coordinator',
+        'election_reason_counter',
+        'election_reason_counter_parser',
+    ],
+)
+
+env.Library(
+    target='election_reason_counter',
+    source=[
+        'election_reason_counter.cpp',
+        env.Idlc('election_reason_counter.idl')[0],
+    ],
+    LIBDEPS=[
+        '$BUILD_DIR/mongo/base',
+        '$BUILD_DIR/mongo/idl/idl_parser',
+    ],
+)
+
+env.Library(
+    target='election_reason_counter_parser',
+    source=[
+        'election_reason_counter_parser.cpp',
+    ],
+    LIBDEPS=[
+        '$BUILD_DIR/mongo/base',
+        'election_reason_counter',
     ],
 )
\ No newline at end of file
diff --git a/src/mongo/db/repl/election_reason_counter.cpp b/src/mongo/db/repl/election_reason_counter.cpp
new file mode 100644
index 00000000000..1ca6db64d64
--- /dev/null
+++ b/src/mongo/db/repl/election_reason_counter.cpp
@@ -0,0 +1,42 @@
+/**
+ *    Copyright (C) 2019-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    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 Server Side 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/election_reason_counter.h"
+
+namespace mongo {
+namespace repl {
+
+ElectionReasonCounter ElectionReasonCounter::parse(const IDLParserErrorContext& ctxt,
+                                                   const BSONObj& bsonObject) {
+    this->parseProtected(ctxt, bsonObject);
+    return *this;
+}
+
+}  // namespace repl
+}  // namespace mongo
diff --git a/src/mongo/db/repl/election_reason_counter.h b/src/mongo/db/repl/election_reason_counter.h
new file mode 100644
index 00000000000..8dd068181b5
--- /dev/null
+++ b/src/mongo/db/repl/election_reason_counter.h
@@ -0,0 +1,53 @@
+/**
+ *    Copyright (C) 2019-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    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 Server Side 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 "mongo/db/repl/election_reason_counter_gen.h"
+
+namespace mongo {
+namespace repl {
+
+/**
+ * Wrapper around the IDL struct ElectionReasonCounterBase that has increment methods.
+ */
+class ElectionReasonCounter : public ElectionReasonCounterBase {
+public:
+    using ElectionReasonCounterBase::getCalled;
+    using ElectionReasonCounterBase::setCalled;
+
+    void incrementCalled() {
+        setCalled(getCalled() + 1);
+    }
+
+    ElectionReasonCounter parse(const IDLParserErrorContext& ctxt, const BSONObj& bsonObject);
+};
+
+}  // namespace repl
+}  // namespace mongo
diff --git a/src/mongo/db/repl/election_reason_counter.idl b/src/mongo/db/repl/election_reason_counter.idl
new file mode 100644
index 00000000000..3cc0059eb13
--- /dev/null
+++ b/src/mongo/db/repl/election_reason_counter.idl
@@ -0,0 +1,51 @@
+# Copyright (C) 2019-present MongoDB, Inc.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the Server Side Public License, version 1,
+# as published by MongoDB, Inc.
+#
+# 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
+# Server Side Public License for more details.
+#
+# You should have received a copy of the Server Side Public License
+# along with this program. If not, see
+# <http://www.mongodb.com/licensing/server-side-public-license>.
+#
+# 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 Server Side 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.
+
+# This IDL file describes the BSON format for ElectionReasonCounterBase and
+# handles the serialization to and deserialization from its BSON
+# representations for that class.
+
+global:
+    cpp_namespace: "mongo::repl"
+
+imports:
+    - "mongo/idl/basic_types.idl"
+
+structs:
+    ElectionReasonCounterBase:
+        description: "Stores the total number of elections a node has called for a given reason and
+                      the number of those elections that were successful"
+        strict: true
+        fields:
+            called:
+                description: "Number of elections this node has called for the given reason"
+                type: long
+                default: 0
+            successful:
+                description: "Number of successful elections for the given reason"
+                type: long
+                default: 0
diff --git a/src/mongo/db/repl/election_reason_counter_parser.cpp b/src/mongo/db/repl/election_reason_counter_parser.cpp
new file mode 100644
index 00000000000..4543b828fd1
--- /dev/null
+++ b/src/mongo/db/repl/election_reason_counter_parser.cpp
@@ -0,0 +1,50 @@
+/**
+ *    Copyright (C) 2019-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    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 Server Side 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/election_reason_counter_parser.h"
+
+namespace mongo {
+namespace repl {
+
+
+ElectionReasonCounter parseElectionReasonCounter(const BSONElement& element) {
+    ElectionReasonCounter counter;
+    IDLParserErrorContext ctxt = IDLParserErrorContext("ElectionReasonCounter");
+
+    return counter.parse(ctxt, element.Obj());
+}
+
+void serializeElectionReasonCounterToBSON(ElectionReasonCounter counter,
+                                          StringData fieldName,
+                                          BSONObjBuilder* builder) {
+    builder->append(fieldName, counter.toBSON());
+}
+
+}  // namespace repl
+}  // namespace mongo
diff --git a/src/mongo/db/repl/election_reason_counter_parser.h b/src/mongo/db/repl/election_reason_counter_parser.h
new file mode 100644
index 00000000000..960021ced2b
--- /dev/null
+++ b/src/mongo/db/repl/election_reason_counter_parser.h
@@ -0,0 +1,44 @@
+/**
+ *    Copyright (C) 2019-present MongoDB, Inc.
+ *
+ *    This program is free software: you can redistribute it and/or modify
+ *    it under the terms of the Server Side Public License, version 1,
+ *    as published by MongoDB, Inc.
+ *
+ *    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
+ *    Server Side Public License for more details.
+ *
+ *    You should have received a copy of the Server Side Public License
+ *    along with this program. If not, see
+ *    <http://www.mongodb.com/licensing/server-side-public-license>.
+ *
+ *    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 Server Side 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 "mongo/db/repl/election_reason_counter.h"
+
+namespace mongo {
+namespace repl {
+
+ElectionReasonCounter parseElectionReasonCounter(const BSONElement& element);
+
+void serializeElectionReasonCounterToBSON(ElectionReasonCounter counter,
+                                          StringData fieldName,
+                                          BSONObjBuilder* builder);
+
+}  // namespace repl
+}  // namespace mongo
diff --git a/src/mongo/db/repl/replication_coordinator_impl.h b/src/mongo/db/repl/replication_coordinator_impl.h
index 2c7c1b7727a..18636ca66f5 100644
--- a/src/mongo/db/repl/replication_coordinator_impl.h
+++ b/src/mongo/db/repl/replication_coordinator_impl.h
@@ -1017,13 +1017,15 @@ private:
      * "originalTerm" was the term during which the dry run began, if the term has since
      * changed, do not run for election.
      */
-    void _processDryRunResult(long long originalTerm);
+    void _processDryRunResult(long long originalTerm,
+                              TopologyCoordinator::StartElectionReason reason);
 
     /**
      * Begins executing a real election. This is called either a successful dry run, or when the
      * dry run was skipped (which may be specified for a ReplSetStepUp).
      */
-    void _startRealElection_inlock(long long originalTerm);
+    void _startRealElection_inlock(long long originalTerm,
+                                   TopologyCoordinator::StartElectionReason reason);
 
     /**
      * Writes the last vote in persistent storage after completing dry run successfully.
diff --git a/src/mongo/db/repl/replication_coordinator_impl_elect_v1.cpp b/src/mongo/db/repl/replication_coordinator_impl_elect_v1.cpp
index ec622e52ba3..b93ba668eb1 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_elect_v1.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_elect_v1.cpp
@@ -34,6 +34,7 @@
 #include <memory>
 
 #include "mongo/db/repl/replication_coordinator_impl.h"
+#include "mongo/db/repl/replication_metrics.h"
 #include "mongo/db/repl/topology_coordinator.h"
 #include "mongo/db/repl/vote_requester.h"
 #include "mongo/stdx/mutex.h"
@@ -143,7 +144,7 @@ void ReplicationCoordinatorImpl::_startElectSelfV1_inlock(
     if (reason == TopologyCoordinator::StartElectionReason::kStepUpRequestSkipDryRun) {
         long long newTerm = term + 1;
         log() << "skipping dry run and running for election in term " << newTerm;
-        _startRealElection_inlock(newTerm);
+        _startRealElection_inlock(newTerm, reason);
         lossGuard.dismiss();
         return;
     }
@@ -169,12 +170,15 @@ void ReplicationCoordinatorImpl::_startElectSelfV1_inlock(
     fassert(28685, nextPhaseEvh.getStatus());
     _replExecutor
         ->onEvent(nextPhaseEvh.getValue(),
-                  [=](const executor::TaskExecutor::CallbackArgs&) { _processDryRunResult(term); })
+                  [=](const executor::TaskExecutor::CallbackArgs&) {
+                      _processDryRunResult(term, reason);
+                  })
         .status_with_transitional_ignore();
     lossGuard.dismiss();
 }
 
-void ReplicationCoordinatorImpl::_processDryRunResult(long long originalTerm) {
+void ReplicationCoordinatorImpl::_processDryRunResult(
+    long long originalTerm, TopologyCoordinator::StartElectionReason reason) {
     stdx::lock_guard<stdx::mutex> lk(_mutex);
     LoseElectionDryRunGuardV1 lossGuard(this);
 
@@ -205,11 +209,14 @@ void ReplicationCoordinatorImpl::_processDryRunResult(long long originalTerm) {
     long long newTerm = originalTerm + 1;
     log() << "dry election run succeeded, running for election in term " << newTerm;
 
-    _startRealElection_inlock(newTerm);
+    _startRealElection_inlock(newTerm, reason);
     lossGuard.dismiss();
 }
 
-void ReplicationCoordinatorImpl::_startRealElection_inlock(long long newTerm) {
+void ReplicationCoordinatorImpl::_startRealElection_inlock(
+    long long newTerm, TopologyCoordinator::StartElectionReason reason) {
+    ReplicationMetrics::get(getServiceContext()).incrementNumElectionsCalledForReason(reason);
+
     LoseElectionDryRunGuardV1 lossGuard(this);
 
     TopologyCoordinator::UpdateTermResult updateTermResult;
diff --git a/src/mongo/db/repl/replication_coordinator_impl_elect_v1_test.cpp b/src/mongo/db/repl/replication_coordinator_impl_elect_v1_test.cpp
index dae9acd510a..27bd7a4653d 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_elect_v1_test.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_elect_v1_test.cpp
@@ -41,6 +41,7 @@
 #include "mongo/db/repl/replication_coordinator_external_state_mock.h"
 #include "mongo/db/repl/replication_coordinator_impl.h"
 #include "mongo/db/repl/replication_coordinator_test_fixture.h"
+#include "mongo/db/repl/replication_metrics.h"
 #include "mongo/db/repl/topology_coordinator.h"
 #include "mongo/executor/network_interface_mock.h"
 #include "mongo/unittest/unittest.h"
@@ -274,6 +275,16 @@ TEST_F(ReplCoordTest, ElectionSucceedsWhenAllNodesVoteYea) {
 
     stopCapturingLogMessages();
     ASSERT_EQUALS(1, countLogLinesContaining("election succeeded"));
+
+    // Check that the numElectionTimeoutsCalled election metric has been incremented, and that none
+    // of the metrics that track the number of elections called for other reasons has been
+    // incremented.
+    ServiceContext* svcCtx = getServiceContext();
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumStepUpCmdsCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumPriorityTakeoversCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumCatchUpTakeoversCalled_forTesting());
+    ASSERT_EQUALS(1, ReplicationMetrics::get(svcCtx).getNumElectionTimeoutsCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumFreezeTimeoutsCalled_forTesting());
 }
 
 TEST_F(ReplCoordTest, ElectionSucceedsWhenMaxSevenNodesVoteYea) {
@@ -1483,6 +1494,16 @@ TEST_F(TakeoverTest, SuccessfulCatchupTakeover) {
     performSuccessfulTakeover(catchupTakeoverTime,
                               TopologyCoordinator::StartElectionReason::kCatchupTakeover,
                               lastVoteExpected);
+
+    // Check that the numCatchUpTakeoversCalled election metric has been incremented, and that none
+    // of the metrics that track the number of elections called for other reasons has been
+    // incremented.
+    ServiceContext* svcCtx = getServiceContext();
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumStepUpCmdsCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumPriorityTakeoversCalled_forTesting());
+    ASSERT_EQUALS(1, ReplicationMetrics::get(svcCtx).getNumCatchUpTakeoversCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumElectionTimeoutsCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumFreezeTimeoutsCalled_forTesting());
 }
 
 TEST_F(TakeoverTest, CatchupTakeoverDryRunFailsPrimarySaysNo) {
@@ -1840,6 +1861,16 @@ TEST_F(TakeoverTest, SuccessfulPriorityTakeover) {
     performSuccessfulTakeover(priorityTakeoverTime,
                               TopologyCoordinator::StartElectionReason::kPriorityTakeover,
                               lastVoteExpected);
+
+    // Check that the numPriorityTakeoversCalled election metric has been incremented, and that none
+    // of the metrics that track the number of elections called for other reasons has been
+    // incremented.
+    ServiceContext* svcCtx = getServiceContext();
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumStepUpCmdsCalled_forTesting());
+    ASSERT_EQUALS(1, ReplicationMetrics::get(svcCtx).getNumPriorityTakeoversCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumCatchUpTakeoversCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumElectionTimeoutsCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumFreezeTimeoutsCalled_forTesting());
 }
 
 TEST_F(TakeoverTest, DontCallForPriorityTakeoverWhenLaggedSameSecond) {
diff --git a/src/mongo/db/repl/replication_coordinator_impl_test.cpp b/src/mongo/db/repl/replication_coordinator_impl_test.cpp
index 6d5a67909b2..1d2fbf52199 100644
--- a/src/mongo/db/repl/replication_coordinator_impl_test.cpp
+++ b/src/mongo/db/repl/replication_coordinator_impl_test.cpp
@@ -55,6 +55,7 @@
 #include "mongo/db/repl/replication_coordinator_external_state_mock.h"
 #include "mongo/db/repl/replication_coordinator_impl.h"
 #include "mongo/db/repl/replication_coordinator_test_fixture.h"
+#include "mongo/db/repl/replication_metrics.h"
 #include "mongo/db/repl/storage_interface_mock.h"
 #include "mongo/db/repl/topology_coordinator.h"
 #include "mongo/db/repl/update_position_args.h"
@@ -2298,6 +2299,16 @@ TEST_F(ReplCoordTest, SingleNodeReplSetUnfreeze) {
     ASSERT_TRUE(getTopoCoord().getMemberState().primary());
     getNet()->exitNetwork();
     ASSERT_TRUE(getReplCoord()->getMemberState().primary());
+
+    // Check that the numFreezeTimeoutsCalled election metric has been incremented, and that none
+    // of the metrics that track the number of elections called for other reasons has been
+    // incremented.
+    ServiceContext* svcCtx = getServiceContext();
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumStepUpCmdsCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumPriorityTakeoversCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumCatchUpTakeoversCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumElectionTimeoutsCalled_forTesting());
+    ASSERT_EQUALS(1, ReplicationMetrics::get(svcCtx).getNumFreezeTimeoutsCalled_forTesting());
 }
 
 TEST_F(ReplCoordTest, NodeBecomesPrimaryAgainWhenStepDownTimeoutExpiresInASingleNodeSet) {
@@ -2314,6 +2325,16 @@ TEST_F(ReplCoordTest, NodeBecomesPrimaryAgainWhenStepDownTimeoutExpiresInASingle
     auto opCtx = makeOperationContext();
     runSingleNodeElection(opCtx.get());
 
+    // Check that the numElectionTimeoutsCalled election metric has been incremented, and that none
+    // of the metrics that track the number of elections called for other reasons has been
+    // incremented.
+    ServiceContext* svcCtx = getServiceContext();
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumStepUpCmdsCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumPriorityTakeoversCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumCatchUpTakeoversCalled_forTesting());
+    ASSERT_EQUALS(1, ReplicationMetrics::get(svcCtx).getNumElectionTimeoutsCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumFreezeTimeoutsCalled_forTesting());
+
     getReplCoord()->stepDown(opCtx.get(), true, Milliseconds(0), Milliseconds(1000));
     getNet()->enterNetwork();  // Must do this before inspecting the topocoord
     Date_t stepdownUntil = getNet()->now() + Seconds(1);
@@ -2328,6 +2349,16 @@ TEST_F(ReplCoordTest, NodeBecomesPrimaryAgainWhenStepDownTimeoutExpiresInASingle
     ASSERT_TRUE(getTopoCoord().getMemberState().primary());
     getNet()->exitNetwork();
     ASSERT_TRUE(getReplCoord()->getMemberState().primary());
+
+    // Check that the numFreezeTimeoutsCalled election metric has been incremented, and that none
+    // of the metrics that track the number of elections called for other reasons has been
+    // incremented. When a stepdown timeout expires in a single node replica set, an election is
+    // called for the same reason as is used when a freeze timeout expires.
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumStepUpCmdsCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumPriorityTakeoversCalled_forTesting());
+    ASSERT_EQUALS(0, ReplicationMetrics::get(svcCtx).getNumCatchUpTakeoversCalled_forTesting());
+    ASSERT_EQUALS(1, ReplicationMetrics::get(svcCtx).getNumElectionTimeoutsCalled_forTesting());
+    ASSERT_EQUALS(1, ReplicationMetrics::get(svcCtx).getNumFreezeTimeoutsCalled_forTesting());
 }
 
 TEST_F(
diff --git a/src/mongo/db/repl/replication_metrics.cpp b/src/mongo/db/repl/replication_metrics.cpp
index 1c1c4075d68..a60d7762a87 100644
--- a/src/mongo/db/repl/replication_metrics.cpp
+++ b/src/mongo/db/repl/replication_metrics.cpp
@@ -27,9 +27,10 @@
  *    it in the license file.
  */
 
-#include "src/mongo/db/repl/replication_metrics.h"
+#include "mongo/db/repl/replication_metrics.h"
 
 #include "mongo/db/commands/server_status.h"
+#include "mongo/db/repl/election_reason_counter.h"
 
 namespace mongo {
 namespace repl {
@@ -46,9 +47,97 @@ ReplicationMetrics& ReplicationMetrics::get(OperationContext* opCtx) {
     return get(opCtx->getServiceContext());
 }
 
+ReplicationMetrics::ReplicationMetrics()
+    : _electionMetrics(ElectionReasonCounter(),
+                       ElectionReasonCounter(),
+                       ElectionReasonCounter(),
+                       ElectionReasonCounter(),
+                       ElectionReasonCounter()) {}
+
+ReplicationMetrics::~ReplicationMetrics() {}
+
+void ReplicationMetrics::incrementNumElectionsCalledForReason(
+    TopologyCoordinator::StartElectionReason reason) {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    switch (reason) {
+        case TopologyCoordinator::StartElectionReason::kStepUpRequest:
+        case TopologyCoordinator::StartElectionReason::kStepUpRequestSkipDryRun: {
+            ElectionReasonCounter& stepUpCmd = _electionMetrics.getStepUpCmd();
+            stepUpCmd.incrementCalled();
+            _electionMetrics.setStepUpCmd(stepUpCmd);
+            break;
+        }
+        case TopologyCoordinator::StartElectionReason::kPriorityTakeover: {
+            ElectionReasonCounter& priorityTakeover = _electionMetrics.getPriorityTakeover();
+            priorityTakeover.incrementCalled();
+            _electionMetrics.setPriorityTakeover(priorityTakeover);
+            break;
+        }
+        case TopologyCoordinator::StartElectionReason::kCatchupTakeover: {
+            ElectionReasonCounter& catchUpTakeover = _electionMetrics.getCatchUpTakeover();
+            catchUpTakeover.incrementCalled();
+            _electionMetrics.setCatchUpTakeover(catchUpTakeover);
+            break;
+        }
+        case TopologyCoordinator::StartElectionReason::kElectionTimeout: {
+            ElectionReasonCounter& electionTimeout = _electionMetrics.getElectionTimeout();
+            electionTimeout.incrementCalled();
+            _electionMetrics.setElectionTimeout(electionTimeout);
+            break;
+        }
+        case TopologyCoordinator::StartElectionReason::kSingleNodePromptElection: {
+            ElectionReasonCounter& freezeTimeout = _electionMetrics.getFreezeTimeout();
+            freezeTimeout.incrementCalled();
+            _electionMetrics.setFreezeTimeout(freezeTimeout);
+            break;
+        }
+    }
+}
+
+int ReplicationMetrics::getNumStepUpCmdsCalled_forTesting() {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    return _electionMetrics.getStepUpCmd().getCalled();
+}
+
+int ReplicationMetrics::getNumPriorityTakeoversCalled_forTesting() {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    return _electionMetrics.getPriorityTakeover().getCalled();
+}
+
+int ReplicationMetrics::getNumCatchUpTakeoversCalled_forTesting() {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    return _electionMetrics.getCatchUpTakeover().getCalled();
+}
+
+int ReplicationMetrics::getNumElectionTimeoutsCalled_forTesting() {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    return _electionMetrics.getElectionTimeout().getCalled();
+}
+
+int ReplicationMetrics::getNumFreezeTimeoutsCalled_forTesting() {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    return _electionMetrics.getFreezeTimeout().getCalled();
+}
+
+BSONObj ReplicationMetrics::getElectionMetricsBSON() {
+    stdx::lock_guard<stdx::mutex> lk(_mutex);
+    return _electionMetrics.toBSON();
+}
+
 class ReplicationMetrics::ElectionMetricsSSS : public ServerStatusSection {
 public:
     ElectionMetricsSSS() : ServerStatusSection("electionMetrics") {}
+
+    bool includeByDefault() const override {
+        return true;
+    }
+
+    BSONObj generateSection(OperationContext* opCtx,
+                            const BSONElement& configElement) const override {
+        ReplicationMetrics& replicationMetrics = ReplicationMetrics::get(opCtx);
+
+        return replicationMetrics.getElectionMetricsBSON();
+    }
 } electionMetricsSSS;
 
 }  // namespace repl
diff --git a/src/mongo/db/repl/replication_metrics.h b/src/mongo/db/repl/replication_metrics.h
index 7012f4802cf..f6c269e7ba0 100644
--- a/src/mongo/db/repl/replication_metrics.h
+++ b/src/mongo/db/repl/replication_metrics.h
@@ -30,6 +30,7 @@
 #pragma once
 
 #include "mongo/db/repl/replication_metrics_gen.h"
+#include "mongo/db/repl/topology_coordinator.h"
 #include "mongo/db/service_context.h"
 #include "mongo/stdx/mutex.h"
 
@@ -47,6 +48,15 @@ public:
     ReplicationMetrics();
     ~ReplicationMetrics();
 
+    void incrementNumElectionsCalledForReason(TopologyCoordinator::StartElectionReason reason);
+    int getNumStepUpCmdsCalled_forTesting();
+    int getNumPriorityTakeoversCalled_forTesting();
+    int getNumCatchUpTakeoversCalled_forTesting();
+    int getNumElectionTimeoutsCalled_forTesting();
+    int getNumFreezeTimeoutsCalled_forTesting();
+
+    BSONObj getElectionMetricsBSON();
+
 private:
     class ElectionMetricsSSS;
 
diff --git a/src/mongo/db/repl/replication_metrics.idl b/src/mongo/db/repl/replication_metrics.idl
index 566d2ee665b..6612eb0216f 100644
--- a/src/mongo/db/repl/replication_metrics.idl
+++ b/src/mongo/db/repl/replication_metrics.idl
@@ -32,22 +32,49 @@
 
 global:
     cpp_namespace: "mongo::repl"
+    cpp_includes:
+        - "mongo/db/repl/election_reason_counter_parser.h"
 
 imports:
     - "mongo/idl/basic_types.idl"
 
+types:
+    ElectionReasonCounter:
+        bson_serialization_type: any
+        description: "Wrapper around ElectionReasonCounterBase that has increment methods"
+        cpp_type: ElectionReasonCounter
+        serializer: "::mongo::repl::serializeElectionReasonCounterToBSON"
+        deserializer: "::mongo::repl::parseElectionReasonCounter"
+
 structs:
     ElectionMetrics:
         description: "Stores metrics related to all the elections a node has called"
         strict: true
         fields:
-            numStepUpsRequested:
-                description: "Number of elections this node has called due to step up requests"
-                type: int
-        
+            stepUpCmd:
+                description: "Election reason counter for step up requests"
+                type: ElectionReasonCounter
+                non_const_getter: true
+            priorityTakeover:
+                description: "Election reason counter for priority takeovers"
+                type: ElectionReasonCounter
+                non_const_getter: true
+            catchUpTakeover:
+                description: "Election reason counter for catchup takeovers"
+                type: ElectionReasonCounter
+                non_const_getter: true
+            electionTimeout:
+                description: "Election reason counter for when the node didn't see a primary in the
+                              past electionTimeoutPeriod milliseconds"
+                type: ElectionReasonCounter
+                non_const_getter: true
+            freezeTimeout:
+                description: "Election reason counter for single node replica set prompt elections"
+                type: ElectionReasonCounter
+                non_const_getter: true
         
     ElectionCandidateMetrics:
-        description: "Stores metrics that are specific to the last election in which the node was a 
+        description: "Stores metrics that are specific to the last election in which the node was a
                       candidate"
         strict: true
         fields: