I checked that I set the parameter to not check the certificate as i'm using 127.0.0.1 instead of the FQDN and #letsencrypt don't provide #certificate for IP addresses

I exec inside the #docker container to run manually the `wget --no-check-certificate`

It's working correctly

When I remove the healthcheck section in #DockerCompose there is no more #zombie process

Root cause found: It's the wget used by the healthcheck that create the zombies !

7/n

ALT

ALT

I summarize: I have #zombie processes created by #wget command when doing an https request in the #healthcheck section of #DockerCompose

Zombie processes occur when child processes have completed execution, and their exit status needs to be read by the parent process.

A process in a #container is still a process on the host, so it takes up a PID on the host. Whatever you run in a container is PID 1 which means it has to install a signal handler to get that signal.

8/n

Next, a #container is a #cgroup of processes running in their own PID namespace. This cgroup is cleaned up when the container is stopped. Any zombies that are in a container are removed on stop. They don't reach the hosts init.

10/n

Third is the different ways containers are used. Most run one main process and nothing else. If there is another process spawned it is usually a child of that main process. So until the parent exits, the zombie will exist. Then see point 2 (the zombies will be cleared on #container exit).

11/n

#Signals

The other role an #init process can provide is to install signal handlers so signals sent from the host can be passed onto the container process. PID 1 is a bit special as it requires the process to listen for a signal for it to be received.

If you can install a SIGINT and SIGTERM signal handler in your PID 1 process then an init process doesn't add much here.

!!! Those explanations come from this superb article in #stackoverflow
https://stackoverflow.com/questions/49162358/docker-init-zombies-why-does-it-matter !!!

12/n

The solution to avoid #zombie in the #container is to use an #init process. This is included by default in #docker thanks to #tini
https://github.com/krallin/tini

13/n

The syntaxe in #DockerCompose is:
init: true

What is advantage of #tini ? https://github.com/krallin/tini/issues/8

14/n

ALT

@slamp hello yes I would like to subscribe to this