Start Docker daemon as another user? - docker

Question

Installed Docker 17.x version in RHEL and we are getting below excetption.
-bash-4.2$ docker version
Client:
Version: 17.09.1-ce
API version: 1.32
Go version: go1.8.3
Git commit: 19e2cf6
Built: Thu Dec 7 22:23:40 2017
OS/Arch: linux/amd64
Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get http://%2Fvar%2Frun%2Fdocker.sock/v1.32/version: dial unix /var/run/docker.sock: connect: permission denied
-bash-4.2$
to solve this , we introduce another user group (docker-user) and we added all the users in this group. after that we ran this command and able to ran docker .
sudo systemctl stop docker
sudo systemctl start docker
cd /var/run
sudo chown :docker-user docker.sock
But we are facing another issue that whenever VM is getting restarted ,DOCKER is not running. So we decided to setup run docker as daemon process and we followed
below steps.
1. create docker.conf file under /etc/systemd/system/docker.service.d folder.
2. added this entry in docker.conf file
[Service]
ExecStart=
ExecStart=/usr/bin/docker daemon -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock
ExecStartPost=/bin/chown :docker-user /var/run/docker.sock
After adding this entry and we ran
1. sudo systemctl daemon-reload
2. sudo systemctl stop docker
3. sudo systemctl start docker
We are getting below exception
-bash-4.2$ sudo systemctl status docker.service
● docker.service - Docker Application Container Engine
Loaded: loaded (/usr/lib/systemd/system/docker.service; disabled; vendor preset: disabled)
Drop-In: /etc/systemd/system/docker.service.d
└─docker.conf
Active: failed (Result: start-limit) since Wed 2018-03-28 09:10:50 PDT; 12s ago
Docs: https://docs.docker.com
Process: 23395 ExecStart=/usr/bin/docker daemon -H tcp://0.0.0.0:2375 -H unix:///var/run/docker.sock (code=exited, status=1/FAILURE)
Main PID: 23395 (code=exited, status=1/FAILURE)
Mar 28 09:10:50 hostname systemd[1]: Failed to start Docker Application Container Engine.
Mar 28 09:10:50 hostname systemd[1]: Unit docker.service entered failed state.
Mar 28 09:10:50 hostname systemd[1]: docker.service failed.
Mar 28 09:10:50 hostname systemd[1]: docker.service holdoff time over, scheduling restart.
Mar 28 09:10:50 hostname systemd[1]: start request repeated too quickly for docker.service
Mar 28 09:10:50 hostname systemd[1]: Failed to start Docker Application Container Engine.
Mar 28 09:10:50 hostname systemd[1]: Unit docker.service entered failed state.
Mar 28 09:10:50 hostname systemd[1]: docker.service failed.
Guide me how to setup docker as daemon process

Answer 1

So, you have already dug in pretty good.
However, this behavior is built into Docker. For user groups, the docker daemon will allow users with the docker group to access the server (important to remember, this is exactly the same as giving root access to any users in that group!). If you wanted to specify a different group, you can start the daemon with the -g option.
Installing docker also installs a systemd service unit to run the daemon. The correct way to enable that (so that it restarts automatically) is
sudo systemctl enable docker
At this point, you didn't include enough of the journalctl logs to actually say why the daemon is not starting for you- if it is an option, I would try starting over since I don't know everything you have messed with, but if that is not an option the journalctl logs will likely explain the problem (probably that the user 'docker' no longer has access to the socket after you chowned it, but that is just a guess)