system/nixos/shared/docker-swarm.nix

{ pkgs, ... }:

{
  # Enable docker
  virtualisation.docker = {
    enable = true;
    liveRestore = false;
    package = pkgs.unstable.docker;
  };
  # Source: https://forums.docker.com/t/error-response-from-daemon-rpc-error-code-unavailable-desc-grpc-the-connection-is-unavailable/39066/12
  networking.firewall = {
    allowedTCPPorts = [ 2376 2377 7946 ];
    allowedUDPPorts = [ 7946 4789 ];
    trustedInterfaces = [ "docker0" "docker_gwbridge" ];
  };
}