Bryan Beaudreault created HBASE-26251:
-----------------------------------------
Summary: StochasticLoadBalancer metrics should update even if
balancer doesn't run
Key: HBASE-26251
URL: https://issues.apache.org/jira/browse/HBASE-26251
Project: HBase
Issue Type: Improvement
Reporter: Bryan Beaudreault
Currently we only update StochasticLoadBalancerMetrics at the very end of a
balancer run, once a plan has been found. In fact, we update the metrics based
on that plan even if we don't end up executing the plan, which seems incorrect.
Regardless of whether the balancer decides to run or not, cluster costs are
changing all the time. Since we don't update these metrics any other time,
operators miss out on important information about the balance of their cluster
over time.
I briefly looked into it and it would be relatively trivial to add another call
to updateStochasticCosts at the beginning of the balanceTable method, before we
determine if the cluster is in need of balancing. This would be an improvement
but would still miss cases where the balancer is disabled or unable to run due
to regions in transition, etc.
We should investigate if it's possible to make updateStochasticCosts get called
periodically regardless of whether the balancer is enabled or can run.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
