Docker 1.10 service does not start with 5.0 module on Centos 7.1

[dcfsc]

We have a Puppet manifest running on Centos 7.1 that uses the 5.0 Docker Puppet module and Docker 1.10. When Puppet installs the Docker service, it creates a file /etc/systemd/system/docker.service.d/service-overrides.conf

[Service]
EnvironmentFile=-/etc/sysconfig/docker
EnvironmentFile=-/etc/sysconfig/docker-storage
EnvironmentFile=-/etc/sysconfig/docker-network
ExecStart=
ExecStart=/usr/bin/docker -d -H fd:// $OPTIONS \
      $DOCKER_STORAGE_OPTIONS \
      $DOCKER_NETWORK_OPTIONS \
      $BLOCK_REGISTRY \
      $INSECURE_REGISTRY

Reviewing the Docker CLI doc it looks like newer Dockers require the argument daemon instead of -d. This was deprecated in 1.8 and removed in 1.10 (see deprecation notice)

So when I change the file to

[Service]
EnvironmentFile=-/etc/sysconfig/docker
EnvironmentFile=-/etc/sysconfig/docker-storage
EnvironmentFile=-/etc/sysconfig/docker-network
ExecStart=
ExecStart=/usr/bin/docker daemon -H fd:// $OPTIONS \
      $DOCKER_STORAGE_OPTIONS \
      $DOCKER_NETWORK_OPTIONS \
      $BLOCK_REGISTRY \
      $INSECURE_REGISTRY

and run systemctl daemon-reload and systemctl restart docker the service comes up fine.

I considered creating a PR to simply change the value, but I think that breaks it for folks using older Docker versions that require the -d instead of daemon, so the value of the argument should probably be in the template. This is above my Ruby-fu level, but I could give it a shot. I did not see another variable in the code deciding what parameter to use anywhere else.

I also thought it might be related to #432, but it does not seem so. Our problem is starting Docker.

[dcfsc]

I think this was fixed in 6107f9b. I am cherry picking it for internal use until the next release.