Writing Dockerfile

SIGTERM

Make sure to pass SIGTERM to the application! Alpine linux does not pass it with the default shell! Use:

CMD [ "myapp" ]

OR:

CMD [ "/bin/bash", "-c", "myapp --arg=$ENV_VAR" ]

Note for kubernetes

Nginx exits violently on SIGTERM, it does not exit gracefully! Use preStop hooks

apiVersion: extensions/v1beta1
kind: Deployment
metadata:
  name: nginx
spec:
  template:
    metadata:
      labels:
        app: nginx
    spec:
      containers:
      - name: nginx
        image: nginx
        ports:
        - containerPort: 80
        lifecycle:
          preStop:
            exec:
              # SIGTERM triggers a quick exit; gracefully terminate instead
              command: ["/usr/sbin/nginx","-s","quit"]

original blog from Marco Pracucci