subscription-manager repos --enable=rhel-7-server-extras-rpms
subscription-manager repos --enable=rhel-7-server-optional-rpms
yum install docker
Docker options are normally stored in /etc/sysconfig/docker
If you want to add additional startup arguments to docker, edit this file:
# /etc/sysconfig/docker
other_args="..."
Placing your arguments in the other_args section, create it if it doensn't exist.
However, other_args won't work, since the service doesn't honour other_args by default, edit /usr/lib/systemd/system/docker.service to add $other_args to the ExecStart setting:
[Unit]
Description=Docker Application Container Engine
Documentation=http://docs.docker.io
After=network.target
[Service]
Type=notify
EnvironmentFile=-/etc/sysconfig/docker
ExecStart=/usr/bin/docker -d --selinux-enabled $other_args
Restart=on-failure
LimitNOFILE=1048576
LimitNPROC=1048576
[Install]
WantedBy=multi-user.target
With --selinux-enabled I found mapping volumes didn't work, with docker not mapping the file permissions correctly.
Doing a docker run -ti -v /var/run/docker.sock:/docker.sock <image> ls -al /, would result in a listing like this:
ls: cannot access /docker.sock: Permission denied
total 8848
dr-xr-xr-x. 22 root root 4096 Jul 4 10:24 .
dr-xr-xr-x. 22 root root 4096 Jul 4 10:24 ..
-rwxr-xr-x. 1 root root 0 Jul 4 10:24 .dockerenv
-rwx------. 1 root root 8979137 Jul 4 08:44 .dockerinit
dr-xr-xr-x. 2 root root 4096 Jun 9 16:14 bin
drwxr-xr-x. 4 root root 360 Jul 4 10:24 dev
-?????????? ? ? ? ? ? docker.sock
drwxr-xr-x. 40 root root 4096 Jul 4 10:24 etc
drwxr-xr-x. 2 root root 4096 Sep 23 2011 home
dr-xr-xr-x. 7 root root 4096 Jun 9 16:14 lib
dr-xr-xr-x. 5 root root 4096 Jun 9 16:14 lib64
drwx------. 2 root root 4096 Jun 9 16:10 lost+found
drwxr-xr-x. 2 root root 4096 Sep 23 2011 media
drwxr-xr-x. 2 root root 4096 Sep 23 2011 mnt
drwxr-xr-x. 2 root root 4096 Sep 23 2011 opt
dr-xr-xr-x. 118 root root 0 Jul 4 10:24 proc
dr-xr-x---. 2 root root 4096 Jun 9 16:14 root
drwxr-xr-x. 3 root root 4096 Jul 4 10:24 run
dr-xr-xr-x. 2 root root 4096 Jun 9 16:14 sbin
drwxr-xr-x. 3 root root 4096 Jun 9 16:14 selinux
drwxr-xr-x. 2 root root 4096 Sep 23 2011 srv
dr-xr-xr-x. 13 root root 0 Jul 4 09:42 sys
drwxrwxrwt. 2 root root 4096 Jun 9 16:14 tmp
drwxr-xr-x. 13 root root 4096 Jun 9 16:12 usr
drwxr-xr-x. 17 root root 4096 Jun 9 16:12 var
With the mapped volume looking like this:
-?????????? ? ? ? ? ? docker.sock
Removing --selinux-enabled from /usr/lib/systemd/system/docker.service fixes this.
See Docker and SELinux.
You could have just run with a --privileged container.