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https://issues.apache.org/jira/browse/KUDU-3802?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Gabriella Lotz updated KUDU-3802:
---------------------------------
Description:
The counters on the auto-rebalancer and the ones added under KUDU-3791 for the
auto-leader-rebalancer report activity: how many moves were scheduled, how many
rounds completed. They don't report whether the cluster is currently skewed.
The replica side already has this: cluster_replica_skew at ts_manager.cc:55 is
a function gauge that returns the difference between the tserver with the most
replicas and the tserver with the fewest.
Add a matching cluster_leader_skew gauge: max minus min leader count across
live tservers. The leader rebalancer already computes this per-round in
RunLeaderRebalancer, so the gauge can share that state or recompute on scrape.
This gives operators a "does the cluster need rebalancing right now" signal to
sit alongside the "is the rebalancer doing anything" signals from the counters.
was:
The counters on the auto-rebalancer and the ones added under KUDU-3791 for the
auto-leader-rebalancer report activity: how many moves were scheduled, how many
rounds completed. They don't report whether the cluster is currently skewed.
The replica side already has this: `cluster_replica_skew` at `ts_manager.cc:55`
is a function gauge that returns the difference between the tserver with the
most replicas and the tserver with the fewest.
Add a matching `cluster_leader_skew` gauge: max minus min leader count across
live tservers. The leader rebalancer already computes this per-round in
`RunLeaderRebalancer`, so the gauge can share that state or recompute on scrape.
This gives operators a "does the cluster need rebalancing right now" signal to
sit alongside the "is the rebalancer doing anything" signals from the counters.
> Add cluster leader-skew gauge
> -----------------------------
>
> Key: KUDU-3802
> URL: https://issues.apache.org/jira/browse/KUDU-3802
> Project: Kudu
> Issue Type: Sub-task
> Reporter: Gabriella Lotz
> Priority: Major
>
> The counters on the auto-rebalancer and the ones added under KUDU-3791 for
> the auto-leader-rebalancer report activity: how many moves were scheduled,
> how many rounds completed. They don't report whether the cluster is currently
> skewed.
> The replica side already has this: cluster_replica_skew at ts_manager.cc:55
> is a function gauge that returns the difference between the tserver with the
> most replicas and the tserver with the fewest.
> Add a matching cluster_leader_skew gauge: max minus min leader count across
> live tservers. The leader rebalancer already computes this per-round in
> RunLeaderRebalancer, so the gauge can share that state or recompute on scrape.
> This gives operators a "does the cluster need rebalancing right now" signal
> to sit alongside the "is the rebalancer doing anything" signals from the
> counters.
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