Starting Docker as Daemon on Ubuntu

Question

Have been using Docker successfully for a few weeks but today when I was following a set of instructions which suggested adding the following two lines to the docker configuration file at /etc/init/docker.conf:

limit memlock unlimited unlimited limit nofile 262144 

It then suggested restarting Docker with sudo /etc/init.d/docker restart. When I did this under Ubuntu 14.04 it reported back that:

• Docker is managed via upstart, try using service docker restart

I tried sudo service docker restart to which it reported:

stop: Unknown job: docker

start: Unknown job: docker

Now I'm stuck with the docker daemon not running! I tried rebooting but it's still not running and when run something as simple as sudo docker version I get:

Client version: 1.2.0 Client API version: 1.14 Go version (client): go1.3.1 Git commit (client): fa7b24f OS/Arch (client): linux/amd64 2014/10/01 09:57:45 Get http:///var/run/docker.sock/v1.14/version: dial unix /var/run/docker.sock: no such file or directory 

To troubleshoot I tried starting the docker daemon on the commandline with:

sudo docker -d 

And in another terminal window I am now able to run Docker normally. That's great but HOW do I get it to startup normally again? Also I notice that I have TWO docker config files:

/etc/init/docker.conf /etc/init/docker.io.conf 

They look like DUPs. Are they redundant? Which one should I be looking at? Do I need both?

I also noticed that this duplicity shows up when I run sudo service --status-all |grep docker I get both docker and docker.io as listed services. Grown.

Answer 1

There are multiple popular repositories offering docker packages for Ubuntu. The package docker.io is (most likely) from the Ubuntu repository. Another popular one is http://get.docker.io/ubuntu which offers a package lxc-docker (I am running the latter because it ships updates faster). Make sure only one package is installed. Not quite sure if removal of the packages cleans up properly. If sudo service docker restart still does not work, you may have to clean up manually in /etc/.

Answer 2

I had the same issue on 14.04 with docker 1.9.1.

The upstart service command did work when I used sudo, even though I was root:

$ whoami root $ service docker status status: Unbekannter Auftrag: docker  $ sudo service docker status docker start/running, process 7394 

---

It seems to depend on the environment variables.

service docker status works when becoming root with su -, but not when only using su:

$ su Password: $ service docker status status: unknown job: docker $ exit $ su - Password: $ service docker status docker start/running, process 2342