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Disable logging in ClusterFormationFailureHelper on shutdown. #125244

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Merged
merged 2 commits into from
Mar 20, 2025
Merged

Disable logging in ClusterFormationFailureHelper on shutdown. #125244

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7bd5628
Disable logging in ClusterFormationFailureHelper on shutdown.
JeremyDahlgren Mar 19, 2025
ba1af37
Update docs/changelog/125244.yaml
JeremyDahlgren Mar 19, 2025
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10 changes: 8 additions & 2 deletions ...r/src/main/java/org/elasticsearch/cluster/coordination/ClusterFormationFailureHelper.java
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Original file line number Diff line number Diff line change
Expand Up @@ -68,6 +68,7 @@ public class ClusterFormationFailureHelper {
private final Runnable logLastFailedJoinAttempt;
@Nullable // if no warning is scheduled
private volatile WarningScheduler warningScheduler;
private volatile boolean loggingEnabled;

/**
* Works with the {@link JoinHelper} to log the latest node-join attempt failure and cluster state debug information. Must call
Expand All @@ -90,6 +91,11 @@ public ClusterFormationFailureHelper(
this.clusterCoordinationExecutor = threadPool.executor(Names.CLUSTER_COORDINATION);
this.clusterFormationWarningTimeout = DISCOVERY_CLUSTER_FORMATION_WARNING_TIMEOUT_SETTING.get(settings);
this.logLastFailedJoinAttempt = logLastFailedJoinAttempt;
this.loggingEnabled = true;
}

public void setLoggingEnabled(boolean enabled) {
this.loggingEnabled = enabled;
Comment on lines +97 to +98
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@JeremyDahlgren JeremyDahlgren Mar 19, 2025 •
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Initially it seemed that a

    synchronized(mutex) {
        clusterFormationFailureHelper.stop();
    }

block in Coordinator::doStop() would be sufficient, but besides needing to hold the lock when the Node is being shut down, it seems a race condition could exist where the failure helper is stopped on shutdown but another thread immediately calls becomeCandidate() and starts it back up?

Also if calls to ClusterFormationFailureHelper start() and stop() were not synchronized it looks like there is the potential for a NullPointerException in start() if the warningScheduler is set to null between the assignment of a new WarningScheduler instance and the next line that calls scheduleNextWarning (Intellij warns about this):

    public void start() {
        assert warningScheduler == null;
        warningScheduler = new WarningScheduler();
        warningScheduler.scheduleNextWarning();
    }

    public void stop() {
        warningScheduler = null;
    }

}

public boolean isRunning() {
Expand All @@ -98,7 +104,7 @@ public boolean isRunning() {

/**
* Schedules a warning debug message to be logged in 'clusterFormationWarningTimeout' time, and periodically thereafter, until
* {@link ClusterFormationState#stop()} has been called.
* {@link ClusterFormationFailureHelper#stop()} has been called.
*/
public void start() {
assert warningScheduler == null;
Expand All @@ -125,7 +131,7 @@ public void onFailure(Exception e) {

@Override
protected void doRun() {
if (isActive()) {
if (isActive() && loggingEnabled) {
logLastFailedJoinAttempt.run();
logger.warn(
"{}; for troubleshooting guidance, see {}",
Expand Down
2 changes: 2 additions & 0 deletions server/src/main/java/org/elasticsearch/cluster/coordination/Coordinator.java
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Expand Up @@ -1104,6 +1104,7 @@ protected void doStart() {
applierState = initialState;
clusterApplier.setInitialState(initialState);
}
clusterFormationFailureHelper.setLoggingEnabled(true);
}

public DiscoveryStats stats() {
Expand All @@ -1126,6 +1127,7 @@ public void startInitialJoin() {
protected void doStop() {
configuredHostsResolver.stop();
joinValidationService.stop();
clusterFormationFailureHelper.setLoggingEnabled(false);
}

@Override
Expand Down
39 changes: 39 additions & 0 deletions .../test/java/org/elasticsearch/cluster/coordination/ClusterFormationFailureHelperTests.java
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Expand Up @@ -171,6 +171,45 @@ public void testScheduling() {

assertThat(warningCount.get(), is(5L));
assertThat(logLastFailedJoinAttemptWarningCount.get(), is(5L));

// Temporarily disable logging and verify we don't get incremented logging counts.
clusterFormationFailureHelper.setLoggingEnabled(false);
warningCount.set(0);
logLastFailedJoinAttemptWarningCount.set(0);
clusterFormationFailureHelper.start();
clusterFormationFailureHelper.stop();
clusterFormationFailureHelper.start();
final long thirdStartTimeMillis = deterministicTaskQueue.getCurrentTimeMillis();

while (deterministicTaskQueue.getCurrentTimeMillis() - thirdStartTimeMillis < 5 * expectedDelayMillis) {
assertTrue(clusterFormationFailureHelper.isRunning());
if (deterministicTaskQueue.hasRunnableTasks()) {
deterministicTaskQueue.runRandomTask();
} else {
deterministicTaskQueue.advanceTime();
}
}

assertThat(warningCount.get(), is(0L));
assertThat(logLastFailedJoinAttemptWarningCount.get(), is(0L));

// Re-enable logging and verify the logging counts again.
clusterFormationFailureHelper.stop();
clusterFormationFailureHelper.start();
clusterFormationFailureHelper.setLoggingEnabled(true);
final long fourthStartTimeMillis = deterministicTaskQueue.getCurrentTimeMillis();

while (warningCount.get() < 5) {
assertTrue(clusterFormationFailureHelper.isRunning());
if (deterministicTaskQueue.hasRunnableTasks()) {
deterministicTaskQueue.runRandomTask();
} else {
deterministicTaskQueue.advanceTime();
}
}
assertThat(deterministicTaskQueue.getCurrentTimeMillis() - fourthStartTimeMillis, equalTo(5 * expectedDelayMillis));
assertThat(warningCount.get(), is(5L));
assertThat(logLastFailedJoinAttemptWarningCount.get(), is(5L));
}

public void testDescriptionOnMasterIneligibleNodes() {
Expand Down
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