I installed docker using snap (during the install process of 22.04) and it was working fine, and all my containers were spun up using docker run ...
This was until I installed docker-compose using apt later on. When I attempted to bring up containers with docker-compose I would get errors stating that the port was already in use.
So I then checked what program/command was using these ports:
sudo lsof -i :9091:
COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME
docker-pr 1883 root 4u IPv4 28696 0t0 TCP *:9091 (LISTEN)
docker-pr 1890 root 4u IPv6 27395 0t0 TCP *:9091 (LISTEN)
sudo netstat -pna | grep 9091
tcp 0 0 0.0.0.0:9091 0.0.0.0:* LISTEN 1883/docker-proxy
tcp6 0 0 :::9091 :::* LISTEN 1890/docker-proxy
This showed that my container was still somehow running, as the port was in use. However, when running docker ps -a no containers were running...
The commands above all pointed towards docker-proxy, what is this service? Also, why is it so under the radar that docker itself can't even stop the container with commands like: docker rm $(docker ps -aq)? Also, not sure why my container became invisible and was unable to stop it without stopping the docker service entirely.