`nerdctl stop` should release rootless ports (OCI `poststop` event should be called on `nerdctl stop`)

[AkihiroSuda]

$ nerdctl --version
nerdctl version 0.12.1-58-g757f823

$ nerdctl run -d --name nginx -p 8080:80 nginx:alpine
5debf438f4632aaf6346d022b8a98c89c36b03e729f21f5e3f89b718a370f2da

$ nerdctl stop nginx
nginx

$ lsof -i -P
COMMAND      PID USER   FD   TYPE  DEVICE SIZE/OFF NODE NAME
rootlessk 131938 suda   12u  IPv6 3543002      0t0  TCP *:8080 (LISTEN)

$ rootlessctl --socket /run/user/1001/containerd-rootless/api.sock list-ports
ID    PROTO    PARENTIP    PARENTPORT    CHILDIP    CHILDPORT    
7     tcp      0.0.0.0     8080                     8080  

The port should be released after nerdctl stop.

It looks like the OCI poststop event hook is not executed for nerdctl stop.

[junnplus]

poststop event hook seems to be a post-delete hook.

[maruno]

A workaround for this issue when using nerdctl for development, if removing the container is okay in your usecase than using nerdctl run --rm will remove all traces of the container after running including the port.

[zhan9san]

It's against the definition of poststop.

IMHO, the runtime-spec is for k8s pod, and there is no stop action in k8s pod.