Graceful shutdown not supported

[ajatprabha]

Description

The current SIGTERM handler function doesn't honour apps/v1.StatefulSet.spec.template.spec.terminationGracePeriodSeconds field to allow graceful shutdown

Expected behaviour

• There should be a DOCKER_VERNEMQ_ env var that can allow adding --timeout=${apps/v1.StatefulSet.spec.template.spec.terminationGracePeriodSeconds}

Actual behaviour

• The leave command doesn't allow for specifying a way to wait for grace period and exits after 60 seconds.
  

  docker-vernemq/bin/vernemq.sh

  Line 179 in 3265897

  /vernemq/bin/vmq-admin cluster leave node=$terminating_node_name -k && rm -rf /vernemq/data/*