chore(shard-manager): Emit metrics on total number of executors#7636
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gazi-yestemirova merged 2 commits intocadence-workflow:masterfrom Jan 23, 2026
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Signed-off-by: Gaziza Yestemirova <gaziza@uber.com>
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arzonus
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Jan 23, 2026
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| p.emitActiveShardMetric(namespaceState.ShardAssignments, metricsLoopScope) | ||
| p.emitExecutorMetric(namespaceState, len(staleExecutors), metricsLoopScope) |
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In case of failures of AssignShards the metric will not be emitted. I think we can emit this metric right before a call of AssignShards
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So, I wanted to emit the "committed" state of the executors after the transaction, because it will be retried, so we avoid potentially emitting inconsistent data.
But I think emitting "observed" state is also reasonable. Let me update it.
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nit: Perhaps, we also should add it for the shadow namespaces, don't we?
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yes, we do, we emit the metric before exiting for shadow executors
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So emitting metric happens right before the shadow executors
Signed-off-by: Gaziza Yestemirova <gaziza@uber.com>
gazi-yestemirova
merged commit 474d530
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cadence-workflow:master
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What changed?
This PR adds shard_distributor_total_executors gauge metric to track the number of executors registered with the shard distributor.
The metric is emitted during each rebalance loop, with executor statuses (e.g., ExecutorStatusACTIVE, ExecutorStatusDRAINING, ExecutorStatusDRAINED.
And it is tagged with namespace and namespace_type for per-namespace monitoring.
Why?
Overall to monitor the health of the shard distributor cluster - know how many executors are actively participating in shard distribution.
To detect executor churn or scaling events
Alert when executor count falls below expected thresholds, which could indicate deployment issues or infrastructure problems.
How did you test it?
Verified metric is emitted in local and dev environments with correct executor counts.
Potential risks
N/A
Release notes
Documentation Changes