Installing Docker¶
Centos 7¶
sudo yum install -y docker
sudo systemctl enable docker
sudo systemctl start docker
sudo groupadd --system dockerroot
sudo chgrp dockerroot /var/run/docker.sock
sudo usermod --append --groups dockerroot $USER
In order for the permissions on docker.sock to persist across service/system
restarts, this line needs to be inserted into the systemd docker service file at
/lib/systemd/system/docker.service/ in the [Service] section.
[Service]
...
ExecStartPost=/usr/bin/chown root:dockerroot /var/run/docker.sock
The service file may be edited by hand or in an automated fashion with augeas
(recommended).
sudo yum install -y augeas
sudo augtool <<'END'
set /files/lib/systemd/system/docker.service/Service/ExecStartPost/command "/usr/bin/chown"
set /files/lib/systemd/system/docker.service/Service/ExecStartPost/arguments/1 "root:dockerroot"
set /files/lib/systemd/system/docker.service/Service/ExecStartPost/arguments/2 "/var/run/docker.sock"
save
END
The group membership change for $USER does not effect shells spawned under the current login session. In order to use docker, the user needs to either logout/login (recommended) or cause a new session to be created. Eg.
exec sudo su -l $USER