KAFKA-14883: Expose `observer` state in KRaft metrics (#13525)

Currently, the current-state KRaft related metric reports follower state for a broker while technically it should be reported as an observer as the kafka-metadata-quorum tool does.

Reviewers: Luke Chen <showuon@gmail.com>, dengziming <dengziming1993@gmail.com>
This commit is contained in:
Paolo Patierno 2023-04-13 06:55:57 +02:00 committed by GitHub
parent 1d5d003ff4
commit 571841fed3
No known key found for this signature in database
GPG Key ID: 4AEE18F83AFDEB23
3 changed files with 9 additions and 4 deletions

View File

@ -1834,7 +1834,7 @@ These metrics are reported on both Controllers and Brokers in a KRaft Cluster
</tr>
<tr>
<td>Current State</td>
<td>The current state of this member; possible values are leader, candidate, voted, follower, unattached.</td>
<td>The current state of this member; possible values are leader, candidate, voted, follower, unattached, observer.</td>
<td>kafka.server:type=raft-metrics,name=current-state</td>
</tr>
<tr>

View File

@ -63,7 +63,7 @@ public class KafkaRaftMetrics implements AutoCloseable {
this.numUnknownVoterConnections = 0;
this.logEndOffset = new OffsetAndEpoch(0L, 0);
this.currentStateMetricName = metrics.metricName("current-state", metricGroupName, "The current state of this member; possible values are leader, candidate, voted, follower, unattached");
this.currentStateMetricName = metrics.metricName("current-state", metricGroupName, "The current state of this member; possible values are leader, candidate, voted, follower, unattached, observer");
Gauge<String> stateProvider = (mConfig, currentTimeMs) -> {
if (state.isLeader()) {
return "leader";
@ -72,7 +72,12 @@ public class KafkaRaftMetrics implements AutoCloseable {
} else if (state.isVoted()) {
return "voted";
} else if (state.isFollower()) {
// a broker is special kind of follower, as not being a voter, it's an observer
if (state.isObserver()) {
return "observer";
} else {
return "follower";
}
} else {
return "unattached";
}

View File

@ -144,7 +144,7 @@ public class KafkaRaftMetricsTest {
assertEquals((double) -1L, getMetric(metrics, "high-watermark").metricValue());
state.transitionToFollower(2, 1);
assertEquals("follower", getMetric(metrics, "current-state").metricValue());
assertEquals("observer", getMetric(metrics, "current-state").metricValue());
assertEquals((double) 1, getMetric(metrics, "current-leader").metricValue());
assertEquals((double) -1, getMetric(metrics, "current-vote").metricValue());
assertEquals((double) 2, getMetric(metrics, "current-epoch").metricValue());