A good Docker entry point
To create a good docker entry point for your image or your container, you must take care of a simple thing. The entry point script must not fail if you run it twice or more.
Indeed, in a container the data is persisted. If you stop and restart a container without removing it, the state/data does not change and can leads to errros.
A bad entry point example.
mv /tmp/nginx/conf.d/default /etc/nginx/conf.d/default nginx &
What is the problem ?
- The first time the container is started, everything works fine.
- The second time the file
/tmp/nginx/conf.d/defaultno more exists and the
mvcommand generates an error.
To bypass the problem, you can remove the container with
docker rm -f container_id|name and restart it.
Test your entry points by executing them twice, at least…