lifecycle

Description

lifecycle allows scripts to be executed after starting and before stopping the DataPower container. For more details on container lifecycle hooks, please refer to the following Kubernetes documentation:

• Container Lifecycle Hooks
• Attach Handlers to Container Lifecycle Events

Delaying SIGTERM with preStop

When the DataPower container is terminated by Kubernetes under normal conditions (such as a scaling event or rolling update), any in-flight transactions may be terminated. The use of the preStop lifecycle hook can help to mitigate this by delaying the SIGTERM being sent to the container. For example, a 20 second delay in the below example would delay the shutdown by 20 seconds giving in-flight transactions on the gateway that much time to complete successfully before being terminated.

spec:
  lifecycle:
    preStop:
      exec:
        command: ["/bin/sh", "-c", "sleep 20"]

Note The preStop handler should complete within terminationGracePeriodSeconds, which by default is 30 seconds. Otherwise it will not prevent the TERM signal being sent to the DataPower container. If a delay longer than 30 seconds is needed, the terminationGracePeriodSeconds can be set to a higher value to accommodate. See the Kubernetes documentation on termination of Pods for a deeper understanding of this lifecycle.

Example

apiVersion: datapower.ibm.com/v1beta3
kind: DataPowerService
metadata:
  name: example-dpservice
spec:
  lifecycle:
    postStart:
      exec:
        command: ["/bin/sh", "-c", "echo Hello from the postStart handler >> ~/lifecycle.log"]
    preStop:
      exec:
        command: ["/bin/sh", "-c", "echo Hello from the preStop handler >> ~/lifecycle.log"]