docker.md

Docker

Build container from dockerfile

$ docker build -t [tag] .

Run container

• Run container detached and exit when the root process used to run the container exits

$ docker run -d [image] [daemon]

• Run container detached and attach a terminal

$ docker run -d -t [image] [command]

• Run container interactively

$ docker run -it [image] [command]

Execute process in running container

$ docker exec -it [container] [command]

Export filesystem

$ docker export [container] > rootfs.tar

Stop and remove all containers

$ docker stop "$(docker ps -a -q)"
$ docker rm "$(docker ps -a -q)"

Dockerfile

FROM debian

RUN apt update
RUN apt install curl -y
RUN cd && curl "https://raw.githubusercontent.com/dylanaraps/promptless/master/install.sh" | sh

CMD /bin/bash -l

Good reaping init file

#!/bin/sh  
  
set -eu  
  
USER=user  
LOG_FILE="/var/log/file.log"  
  
cleanup(){  
       #printf '=> Received SIGTERM, reaping procesess... '  
  
       kill -15 "$PROCESS1" || true  
       kill -15 "$PROCESS2" || true  
       wait  
       #echo OK  
  
       #echo '=> All done, exiting'  
       exit 0  
}  
  
#printf '=> Setting up trap...'  
trap 'cleanup' 15  
#echo OK  
  
#printf '=> Start process1 in the background... '  
/bin/su - "$USER" -c "exec process1" &  
PROCESS1="$!"  
#echo OK  
  
#printf '=> Starting process2 process... '  
/bin/su - "$USER" -c "exec process" &  
PROCESS2="$!"  
#echo OK  
  
#echo '=> Startup finished.'  
  
wait

Good Dockerfile

FROM docker.io/debian:stable-slim  

RUN apt-get -q update \  
       && apt-get -y dist-upgrade \  
       && apt-get -q install -y --no-install-recommends apt-utils curl iproute2 openresolv procps qbittorrent-nox util-linux  
wireguard-tools \  
       && rm -rf /var/lib/apt/lists/* \  
       && useradd -m qbit \  
       && chown -R qbit:qbit /home/qbit  

COPY ./init /init  

WORKDIR /home/qbit  

ENTRYPOINT ["/init"]  

EXPOSE 8080  

HEALTHCHECK CMD pgrep qbittorrent-nox && curl -v gnu.org

User docker with podman socket

systemctl --user enable --now podman.socket
export DOCKER_HOST=unix:///run/user/$UID/podman/podman.sock