2.6.x CoordinatedShutdown reason

igmar · January 4, 2022, 7:17pm

Hi,

I’m looking at a way to automatically restart Akka Cluster nodes. Currently, we just register a JVM shutdown hook, and exit with a fixed status.
This doesn’t allow differentiating between a ‘normal’ shutdown, and a node getting kicked out of the cluster.

I found a few (old) issues, but most where closed with a reference to Coordinated Shutdown. Looking at the API, it doesn’t pass along the reason, and is more about the shutdown order then the reason for the shutdown.

Do I miss something ? Can anyone shed a light on this ?

Regards,

Igmar

johanandren · January 5, 2022, 11:05am

If you instead use the build in shutdown hook, it uses the exit code configured for the reason it shut down:

github.com

akka/akka/blob/main/akka-actor/src/main/resources/reference.conf#L1190

    
      
          
          
# Run the coordinated shutdown when ActorSystem.terminate is called.
          # Enabling this and disabling terminate-actor-system is not a supported
          # combination (will throw ConfigurationException at startup).
          run-by-actor-system-terminate = on
          
          
# When Coordinated Shutdown is triggered an instance of `Reason` is
          # required. That value can be used to override the default settings.
          # Only 'exit-jvm', 'exit-code' and 'terminate-actor-system' may be
          # overridden depending on the reason.
          reason-overrides {
            # Overrides are applied using the `reason.getClass.getName`.
            # Overrides the `exit-code` when the `Reason` is a cluster
            # Downing or a Cluster Join Unsuccessful event
            "akka.actor.CoordinatedShutdown$ClusterDowningReason$" {
              exit-code = -1
            }
            "akka.actor.CoordinatedShutdown$ClusterJoinUnsuccessfulReason$" {
              exit-code = -1
            }
          }

igmar · January 5, 2022, 11:16am

Ah, nice. I didn’t look in the reference.conf. Can this also be done in code ?

johanandren · January 5, 2022, 12:28pm

It’s only possible to set through configuration (which can be constructed by code though).

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2.6.x CoordinatedShutdown reason

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