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https://issues.apache.org/jira/browse/HDDS-14212?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Sammi Chen updated HDDS-14212:
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Fix Version/s: 2.2.0
Resolution: Fixed
Status: Resolved (was: Patch Available)
> S3G stuck on failover to a new leader OM
> ----------------------------------------
>
> Key: HDDS-14212
> URL: https://issues.apache.org/jira/browse/HDDS-14212
> Project: Apache Ozone
> Issue Type: Bug
> Components: S3, s3gateway
> Reporter: Aleksei Ieshin
> Assignee: Aleksei Ieshin
> Priority: Major
> Labels: pull-request-available
> Fix For: 2.2.0
>
>
> As per discussion here: [https://github.com/apache/ozone/discussions/9477]
> Our ozone cluster is running with kube; we have a bunch of kube nodes, each
> node has one S3g and one DN running. Some kube nodes additionally have one OM
> or one SCM instance running. We have three OMs: om0, om1, and om2.
> So, for some reason, one of the kube nodes with S3g, DN, and *om0* (leader)
> running went into a non-Ready state for a few minutes (so om1 was still
> running but didn't serve any traffic). That caused *om2* to take over the
> leadership. A few seconds later, *om1* returned to the cluster.
> All S3gs failed over to the new OM leader, except one, which stuck in that
> failover attempts mode. Restarting that failing S3g helped resolve the issues.
> h4. Investigation
> Later, the investigation showed the following:
> # Cluster had a very low (non-default) setting that made it quickly exhaust
> its failover limits
> {code:java}
> "ozone.client.wait.between.retries.millis": "250"
> "ozone.client.failover.max.attempts": "16"
> {code}
> -
> `hadoop-ozone/common/src/main/java/org/apache/hadoop/ozone/om/protocolPB/GrpcOmTransport.java`
> line 93: we have `private int failoverCount = 0;` - All threads share this
> counter; it never resets.
> - Also, in `GrpcOmTransport.shouldRetry`(258) we run `action =
> retryPolicy.shouldRetry((Exception)ex, 0, failoverCount++, true);` which is
> also shared between requests.
> - Next in `OMFailoverProxyProviderBase.getRetryPolicy.getRetryAction`, we
> still use that global `failoverCount` checking ` if (failovers <
> maxFailovers)`(258), which always returns `return RetryAction.FAIL;`(263)
> once we reached the `maxFailovers`
> I propose to change the value of *failoverCount* per request, rather than
> making it a global flag.
>
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