dockerd not running on nixos

Question

I installed docker on nixos, using:

nix-env -i docker

after that, dockerd was not running, so I started the daemon manually with:

dockerd

and in the logs, I see:

WARN[2019-06-26T01:02:31.784701442Z] could not change group /var/run/docker.sock to docker: group docker not found

should I care about this warning?

Answer 1

When installing docker on NixOS, it's best to enable it in the NixOS configuration. Doing so will install docker as a system service.

Snippet for /etc/nixos/configuration.nix:

virtualisation.docker.enable = true;

# ...

users.users.YOU = { # merge this with your unix user definition, "YOU" is for illustration
  isNormalUser = true;
  # ...
  extraGroups = [
    # ...
    "docker"
  ];
};

Answer 2

created a group docker. Docker needs that user group to start as a service.