I'm using Flink 1.15.4.
One time, I found the job failed to restart on time, here are some of my
jobManager's log:
```
2024-12-30 18:50:32,089 INFO org.apache.flink.runtime.jobmaster.JobMaster
[] - Using restart back off time strategy
FixedDelayRestartBackoffTimeStrategy(maxNumberRestartAttempts=15,
backoffTimeMS=30000) for XXX (77ae983fe1ccdb4b6a8dffdd3754fcdb).
2025-01-06 03:08:25,556 INFO
org.apache.flink.runtime.executiongraph.ExecutionGraph [] - XXX
(77ae983fe1ccdb4b6a8dffdd3754fcdb) switched from state RUNNING to RESTARTING.
2025-01-06 03:08:26,746 INFO
org.apache.flink.runtime.resourcemanager.slotmanager.DeclarativeSlotManager []
- Received resource requirements from job 77ae983fe1ccdb4b6a8dffdd3754fcdb:
[ResourceRequirement{resourceProfile=ResourceProfile{UNKNOWN},
numberOfRequiredSlots=1}]
2025-01-06 03:10:02,193 INFO
org.apache.flink.runtime.jobmaster.slotpool.DefaultDeclarativeSlotPool [] -
Releasing slot [530442f543a64060c85150a407a1b3e7].
2025-01-06 03:10:02,198 INFO
org.apache.flink.runtime.jobmaster.slotpool.DefaultDeclarativeSlotPool [] -
Releasing slot [e43037827cef57edecf298e1378075dd].
```
The restart stragety is maxNumberRestartAttempts=15, backoffTimeMS=30000.
The job status switched to RESTARTING at 2024-12-30 18:50:32,089, However, it
didn't restart at 30S after it failed.
