[ https://issues.apache.org/jira/browse/FLINK-34451 ]


    Gyula Fora deleted comment on FLINK-34451:
    ------------------------------------

was (Author: gyfora):
[~alexdchoffer] so, just to confirm:

This issue doesn't occur with Flink 1.18? (even with the adaptive scheduler)

> [Kubernetes Operator] Job with restarting TaskManagers uses wrong/misleading 
> fallback approach
> ----------------------------------------------------------------------------------------------
>
>                 Key: FLINK-34451
>                 URL: https://issues.apache.org/jira/browse/FLINK-34451
>             Project: Flink
>          Issue Type: Bug
>          Components: Kubernetes Operator
>    Affects Versions: kubernetes-operator-1.6.1
>         Environment: Operator version: 1.6.1
> Flink version 1.18.0
> HA JobManagers
> Adaptive scheduler mode using the operator's autoscaler
> Checkpointing at an interval of 60s
> Upgrade mode savepoint
>            Reporter: Alex Hoffer
>            Priority: Major
>
>  
> We had a situation where TaskManagers were constantly restarting from OOM. 
> We're using the Adaptive scheduler with the Kubernetes Operator, and a 
> restart strategy of exponential backoff, and so the JobManagers remained 
> alive. We're also using savepoint upgrade mode. 
> When we tried to remedy the situation by raising the direct memory allocation 
> to the pods, we were surprised that Flink used the last savepoint taken, 
> rather than the checkpoint. This was unfortunate for us because we are on 
> adaptive scheduler and the job hasn't changed in some time, so this last 
> savepoint was 6 days old! Meanwhile, checkpoints were taken every minute up 
> until failure. I can confirm the HA metadata existed in the configmaps, and 
> the corresponding checkpoints existed in remote storage for it to access. 
> Plus, no Flink version changes were in the deployment.
> The Operator logs reported that it was using last-state recovery in this 
> situation:
> {code:java}
> 2024-02-15 19:38:38,252 o.a.f.k.o.l.AuditUtils         [INFO ][job-name] >>> 
> Event  | Info    | SPECCHANGED     | UPGRADE change(s) detected (Diff: 
> FlinkDeploymentSpec[image : image:0a7c41b -> image:ebebc53, restartNonce : 
> null -> 100]), starting reconciliation.
> 2024-02-15 19:38:38,252 o.a.f.k.o.r.d.AbstractJobReconciler [INFO ][job-name] 
> Upgrading/Restarting running job, suspending first...
> 2024-02-15 19:38:38,260 o.a.f.k.o.r.d.ApplicationReconciler [INFO ][job-name] 
> Job is not running but HA metadata is available for last state restore, ready 
> for upgrade
> 2024-02-15 19:38:38,270 o.a.f.k.o.l.AuditUtils         [INFO ][job-name] >>> 
> Event  | Info    | SUSPENDED       | Suspending existing deployment.
> 2024-02-15 19:38:38,270 o.a.f.k.o.s.NativeFlinkService [INFO ][job-name] 
> Deleting JobManager deployment while preserving HA metadata. 
> 2024-02-15 19:38:40,431 o.a.f.k.o.l.AuditUtils         [INFO ][job-name] >>> 
> Status | Info    | UPGRADING       | The resource is being upgraded 
> 2024-02-15 19:38:40,532 o.a.f.k.o.l.AuditUtils         [INFO ][job-name] >>> 
> Event  | Info    | SUBMIT          | Starting deployment
> 2024-02-15 19:38:40,532 o.a.f.k.o.s.AbstractFlinkService [INFO ][job-name] 
> Deploying application cluster requiring last-state from HA metadata
> 2024-02-15 19:38:40,538 o.a.f.k.o.u.FlinkUtils         [INFO ][job-name] Job 
> graph in ConfigMap job-name-cluster-config-map is deleted {code}
> But when the job booted up, it reported restoring from savepoint:
> {code:java}
> 2024-02-15 19:39:03,887 INFO  
> org.apache.flink.runtime.checkpoint.CheckpointCoordinator    [] - Restoring 
> job 522b3c363499d81ed7922aa30b13e237 from Savepoint 20207 @ 0 for 
> 522b3c363499d81ed7922aa30b13e237 located at 
> abfss://savepoi...@storageaccount.dfs.core.windows.net/job-name/savepoint-522b3c-8836a1edc709.
>  {code}
> Our expectation was that the Operator logs were true, and that it would be 
> restoring from checkpoint. We had to scramble and manually restore from the 
> checkpoint to restore function.
>  
>  
> It's also worth noting I can recreate this issue in a testing environment. 
> The process for doing so is:
> - Boot up HA JobManagers with checkpoints on and savepoint upgrade mode, 
> using adaptive scheduler
> - Make a dummy change to trigger a savepoint.
> - Allow the TaskManagers to process some data and hit the checkpoint interval.
> - Cause the TaskManagers to crash. In our case, we could use up a bunch of 
> memory in the pods and cause it to crash.
> - Observe the Operator logs saying it is restoring from last-state, but watch 
> as the pods instead use the last savepoint.



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