Adds counter metrics for leader and follower check failures (opensear…

…ch-project#12439)

* Adds counter metrics for leader and follower check failures

Signed-off-by: Harsh Garg <gkharsh@amazon.com>

CHANGELOG.md

@@ -5,6 +5,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [Unreleased 2.x]
 ### Added
+- Add leader and follower check failure counter metrics ([#12439](https://github.com/opensearch-project/OpenSearch/pull/12439))
 - Add latency metrics for instrumenting critical clusterManager code paths ([#12333](https://github.com/opensearch-project/OpenSearch/pull/12333))
 - Add support for Azure Managed Identity in repository-azure ([#12423](https://github.com/opensearch-project/OpenSearch/issues/12423))
 - Add useCompoundFile index setting ([#13478](https://github.com/opensearch-project/OpenSearch/pull/13478))

server/src/main/java/org/opensearch/cluster/ClusterManagerMetrics.java

@@ -8,6 +8,7 @@
 
 package org.opensearch.cluster;
 
+import org.opensearch.telemetry.metrics.Counter;
 import org.opensearch.telemetry.metrics.Histogram;
 import org.opensearch.telemetry.metrics.MetricsRegistry;
 import org.opensearch.telemetry.metrics.tags.Tags;
@@ -23,13 +24,17 @@
 public final class ClusterManagerMetrics {
 
     private static final String LATENCY_METRIC_UNIT_MS = "ms";
+    private static final String COUNTER_METRICS_UNIT = "1";
 
     public final Histogram clusterStateAppliersHistogram;
     public final Histogram clusterStateListenersHistogram;
     public final Histogram rerouteHistogram;
     public final Histogram clusterStateComputeHistogram;
     public final Histogram clusterStatePublishHistogram;
 
+    public final Counter leaderCheckFailureCounter;
+    public final Counter followerChecksFailureCounter;
+
     public ClusterManagerMetrics(MetricsRegistry metricsRegistry) {
         clusterStateAppliersHistogram = metricsRegistry.createHistogram(
             "cluster.state.appliers.latency",
@@ -56,6 +61,16 @@ public ClusterManagerMetrics(MetricsRegistry metricsRegistry) {
             "Histogram for recording time taken to publish a new cluster state",
             LATENCY_METRIC_UNIT_MS
         );
+        followerChecksFailureCounter = metricsRegistry.createCounter(
+            "followers.checker.failure.count",
+            "Counter for number of failed follower checks",
+            COUNTER_METRICS_UNIT
+        );
+        leaderCheckFailureCounter = metricsRegistry.createCounter(
+            "leader.checker.failure.count",
+            "Counter for number of failed leader checks",
+            COUNTER_METRICS_UNIT
+        );
     }
 
     public void recordLatency(Histogram histogram, Double value) {
@@ -69,4 +84,16 @@ public void recordLatency(Histogram histogram, Double value, Optional<Tags> tags
         }
         histogram.record(value, tags.get());
     }
+
+    public void incrementCounter(Counter counter, Double value) {
+        incrementCounter(counter, value, Optional.empty());
+    }
+
+    public void incrementCounter(Counter counter, Double value, Optional<Tags> tags) {
+        if (Objects.isNull(tags) || tags.isEmpty()) {
+            counter.add(value);
+            return;
+        }
+        counter.add(value, tags.get());
+    }
 }

server/src/main/java/org/opensearch/cluster/coordination/Coordinator.java

@@ -36,6 +36,7 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.cluster.ClusterChangedEvent;
+import org.opensearch.cluster.ClusterManagerMetrics;
 import org.opensearch.cluster.ClusterName;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.ClusterStateTaskConfig;
@@ -207,7 +208,8 @@ public Coordinator(
         ElectionStrategy electionStrategy,
         NodeHealthService nodeHealthService,
         PersistedStateRegistry persistedStateRegistry,
-        RemoteStoreNodeService remoteStoreNodeService
+        RemoteStoreNodeService remoteStoreNodeService,
+        ClusterManagerMetrics clusterManagerMetrics
     ) {
         this.settings = settings;
         this.transportService = transportService;
@@ -261,14 +263,22 @@ public Coordinator(
             this::handlePublishRequest,
             this::handleApplyCommit
         );
-        this.leaderChecker = new LeaderChecker(settings, clusterSettings, transportService, this::onLeaderFailure, nodeHealthService);
+        this.leaderChecker = new LeaderChecker(
+            settings,
+            clusterSettings,
+            transportService,
+            this::onLeaderFailure,
+            nodeHealthService,
+            clusterManagerMetrics
+        );
         this.followersChecker = new FollowersChecker(
             settings,
             clusterSettings,
             transportService,
             this::onFollowerCheckRequest,
             this::removeNode,
-            nodeHealthService
+            nodeHealthService,
+            clusterManagerMetrics
         );
         this.nodeRemovalExecutor = new NodeRemovalClusterStateTaskExecutor(allocationService, logger);
         this.clusterApplier = clusterApplier;

server/src/main/java/org/opensearch/cluster/coordination/FollowersChecker.java

@@ -35,6 +35,7 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
+import org.opensearch.cluster.ClusterManagerMetrics;
 import org.opensearch.cluster.coordination.Coordinator.Mode;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
@@ -127,14 +128,16 @@ public class FollowersChecker {
     private final TransportService transportService;
     private final NodeHealthService nodeHealthService;
     private volatile FastResponseState fastResponseState;
+    private ClusterManagerMetrics clusterManagerMetrics;
 
     public FollowersChecker(
         Settings settings,
         ClusterSettings clusterSettings,
         TransportService transportService,
         Consumer<FollowerCheckRequest> handleRequestAndUpdateState,
         BiConsumer<DiscoveryNode, String> onNodeFailure,
-        NodeHealthService nodeHealthService
+        NodeHealthService nodeHealthService,
+        ClusterManagerMetrics clusterManagerMetrics
     ) {
         this.settings = settings;
         this.transportService = transportService;
@@ -161,6 +164,7 @@ public void onNodeDisconnected(DiscoveryNode node, Transport.Connection connecti
                 handleDisconnectedNode(node);
             }
         });
+        this.clusterManagerMetrics = clusterManagerMetrics;
     }
 
     private void setFollowerCheckTimeout(TimeValue followerCheckTimeout) {
@@ -413,6 +417,7 @@ public String executor() {
         }
 
         void failNode(String reason) {
+            clusterManagerMetrics.incrementCounter(clusterManagerMetrics.followerChecksFailureCounter, 1.0);
             transportService.getThreadPool().generic().execute(new Runnable() {
                 @Override
                 public void run() {

server/src/main/java/org/opensearch/cluster/coordination/LeaderChecker.java

@@ -36,6 +36,7 @@
 import org.apache.logging.log4j.Logger;
 import org.apache.logging.log4j.message.ParameterizedMessage;
 import org.opensearch.OpenSearchException;
+import org.opensearch.cluster.ClusterManagerMetrics;
 import org.opensearch.cluster.node.DiscoveryNode;
 import org.opensearch.cluster.node.DiscoveryNodes;
 import org.opensearch.common.Nullable;
@@ -119,17 +120,17 @@ public class LeaderChecker {
     private final TransportService transportService;
     private final Consumer<Exception> onLeaderFailure;
     private final NodeHealthService nodeHealthService;
-
     private AtomicReference<CheckScheduler> currentChecker = new AtomicReference<>();
-
     private volatile DiscoveryNodes discoveryNodes;
+    private final ClusterManagerMetrics clusterManagerMetrics;
 
     LeaderChecker(
         final Settings settings,
         final ClusterSettings clusterSettings,
         final TransportService transportService,
         final Consumer<Exception> onLeaderFailure,
-        NodeHealthService nodeHealthService
+        NodeHealthService nodeHealthService,
+        final ClusterManagerMetrics clusterManagerMetrics
     ) {
         this.settings = settings;
         leaderCheckInterval = LEADER_CHECK_INTERVAL_SETTING.get(settings);
@@ -138,6 +139,7 @@ public class LeaderChecker {
         this.transportService = transportService;
         this.onLeaderFailure = onLeaderFailure;
         this.nodeHealthService = nodeHealthService;
+        this.clusterManagerMetrics = clusterManagerMetrics;
         clusterSettings.addSettingsUpdateConsumer(LEADER_CHECK_TIMEOUT_SETTING, this::setLeaderCheckTimeout);
 
         transportService.registerRequestHandler(
@@ -293,7 +295,6 @@ public void handleResponse(Empty response) {
                             logger.debug("closed check scheduler received a response, doing nothing");
                             return;
                         }
-
                         failureCountSinceLastSuccess.set(0);
                         scheduleNextWakeUp(); // logs trace message indicating success
                     }
@@ -304,7 +305,6 @@ public void handleException(TransportException exp) {
                             logger.debug("closed check scheduler received a response, doing nothing");
                             return;
                         }
-
                         if (exp instanceof ConnectTransportException || exp.getCause() instanceof ConnectTransportException) {
                             logger.debug(new ParameterizedMessage("leader [{}] disconnected during check", leader), exp);
                             leaderFailed(new ConnectTransportException(leader, "disconnected during check", exp));
@@ -355,6 +355,7 @@ public String executor() {
 
         void leaderFailed(Exception e) {
             if (isClosed.compareAndSet(false, true)) {
+                clusterManagerMetrics.incrementCounter(clusterManagerMetrics.leaderCheckFailureCounter, 1.0);
                 transportService.getThreadPool().generic().execute(new Runnable() {
                     @Override
                     public void run() {

server/src/main/java/org/opensearch/discovery/DiscoveryModule.java

@@ -34,6 +34,7 @@
 
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
+import org.opensearch.cluster.ClusterManagerMetrics;
 import org.opensearch.cluster.ClusterState;
 import org.opensearch.cluster.coordination.Coordinator;
 import org.opensearch.cluster.coordination.ElectionStrategy;
@@ -133,7 +134,8 @@ public DiscoveryModule(
         RerouteService rerouteService,
         NodeHealthService nodeHealthService,
         PersistedStateRegistry persistedStateRegistry,
-        RemoteStoreNodeService remoteStoreNodeService
+        RemoteStoreNodeService remoteStoreNodeService,
+        ClusterManagerMetrics clusterManagerMetrics
     ) {
         final Collection<BiConsumer<DiscoveryNode, ClusterState>> joinValidators = new ArrayList<>();
         final Map<String, Supplier<SeedHostsProvider>> hostProviders = new HashMap<>();
@@ -211,7 +213,8 @@ public DiscoveryModule(
                 electionStrategy,
                 nodeHealthService,
                 persistedStateRegistry,
-                remoteStoreNodeService
+                remoteStoreNodeService,
+                clusterManagerMetrics
             );
         } else {
             throw new IllegalArgumentException("Unknown discovery type [" + discoveryType + "]");

server/src/main/java/org/opensearch/node/Node.java

@@ -1199,7 +1199,8 @@ protected Node(
                 rerouteService,
                 fsHealthService,
                 persistedStateRegistry,
-                remoteStoreNodeService
+                remoteStoreNodeService,
+                clusterManagerMetrics
             );
             final SearchPipelineService searchPipelineService = new SearchPipelineService(
                 clusterService,