Rootless Docker-Compose with Podman

One of the benefits of Podman over Docker is that it can run daemon-less and without root. However, docker-compose is by far my favorite way to create and maintain containers. Luckily, the Podman folks emulated the Docker CLI so that docker-compose works well with Podman!

To install:

sudo dnf install -y podman podman-docker docker-compose

We can then emulate the docker socket rootless with the following commands:

systemctl --user enable podman.socket
systemctl --user start podman.socket

At this point, we’ll want to see if the daemon acts as expected

curl -H "Content-Type: application/json" \
    --unix-socket /var/run/user/$UID/podman/podman.sock \
    http://localhost/_ping

This should return OK. We then need to create an environmental variable to tell docker compose where the emulated docker socket lives.

export DOCKER_HOST=unix:///run/user/$UID/podman/podman.sock

To have this environmental variable persistent across reboots, add the above line to the user’s .bash_profile.

You’ll need a configuration file docker-compose.yml defined. Here is a sample one that spins up an image updating service.

version: "3.3"

services:
  watchtower:
    image: docker.io/containrrr/watchtower 
    container_name: watchtower
    hostname: watchtower
    environment:
      PUID: 1000
      PGID: 1000
      TZ: US/Eastern
    volumes:
      - /var/run/podman/podman.sock:/var/run/docker.sock:ro
    restart: always

If you want to add to add more volumes to the container, make sure it has the appropriate SELinux label if you’re using a distribution with it enabled.¹

chcon -t container_file_t -R X

where X is the volume you wish to mount.

Now we can run docker-compose!

docker-compose ps

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1. https://bugzilla.redhat.com/show_bug.cgi?id=2125878 ↩︎