Xiangyan created FLINK-33998:
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Summary: Flink Job Manager restarted after kube-apiserver
connection intermittent
Key: FLINK-33998
URL: https://issues.apache.org/jira/browse/FLINK-33998
Project: Flink
Issue Type: Bug
Components: Deployment / Kubernetes
Affects Versions: 1.13.6
Environment: Kubernetes 1.24
Flink Operator 1.4
Flink 1.13.6
Reporter: Xiangyan
Attachments: audit-log-no-restart.txt, audit-log-restart.txt,
connection timeout.png, jm-no-restart4.log, jm-restart4.log
We are running Flink on AWS EKS and experienced Job Manager restart issue when
EKS control plane scaled up/in.
I can reproduce this issue in my local environment too.
Since I have no control of EKS kube-apiserver, I built a Kubernetes cluster by
my own with below setup:
* Two kube-apiserver, only one is running at a time;
* Deploy multiple Flink clusters (with Flink Operator 1.4 and Flink 1.13);
* Enable Flink Job Manager HA;
* Configure Job Manager leader election timeout;
high-availability.kubernetes.leader-election.lease-duration: "60s"
high-availability.kubernetes.leader-election.renew-deadline: "60s"
For testing, I switch the running kube-apiserver from one instance to another
each time. When the kube-apiserver is switching, I can see that some Job
Managers restart, but some are still running normally.
Here is an example. When kube-apiserver swatched over at 05:{{{}*53*{}}}:08,
both JM lost connection to kube-apiserver. But there is no more connection
error within a few seconds. I guess the connection recovered by retry.
However, one of the JM (the 2nd one in the attached screen shot) reported
"leadership revoked" error after the leader election timeout (at
05:{{{}*54*{}}}:08) and then restarted itself. While the other JM was still
running normally.
>From kube-apiserver audit logs, the normal JM was able to renew leader lease
>after the interruption. But there is no any lease renew request from the
>failed JM until it restarted.
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