Oracle Linux
Docker is supported Oracle Linux 6 and 7. You do not require an Oracle Linux Support subscription to install Docker on Oracle Linux.
Prerequisites
Due to current Docker limitations, Docker is only able to run only on the x86_64 architecture. Docker requires the use of the Unbreakable Enterprise Kernel Release 4 (4.1.12) or higher on Oracle Linux. This kernel supports the Docker btrfs storage engine on both Oracle Linux 6 and 7.
Install
Note: The procedure below installs binaries built by Docker. These binaries are not covered by Oracle Linux support. To ensure Oracle Linux support, please follow the installation instructions provided in the Oracle Linux documentation.
The installation instructions for Oracle Linux 6 and 7 can be found in Chapter 2 of the Docker User's Guide
Log into your machine as a user with
sudo
orroot
privileges.-
Make sure your existing yum packages are up-to-date.
$ sudo yum update
-
Add the yum repo yourself.
For version 6:
$ sudo tee /etc/yum.repos.d/docker.repo <<-EOF [dockerrepo] name=Docker Repository baseurl=https://yum.dockerproject.org/repo/main/oraclelinux/6 enabled=1 gpgcheck=1 gpgkey=https://yum.dockerproject.org/gpg EOF
For version 7:
$ cat >/etc/yum.repos.d/docker.repo <<-EOF [dockerrepo] name=Docker Repository baseurl=https://yum.dockerproject.org/repo/main/oraclelinux/7 enabled=1 gpgcheck=1 gpgkey=https://yum.dockerproject.org/gpg EOF
-
Install the Docker package.
$ sudo yum install docker-engine
-
Start the Docker daemon.
On Oracle Linux 6:
$ sudo service docker start
On Oracle Linux 7:
$ sudo systemctl start docker.service
-
Verify
docker
is installed correctly by running a test image in a container.$ sudo docker run hello-world
Optional configurations
This section contains optional procedures for configuring your Oracle Linux to work better with Docker.
Create a Docker group
The docker
daemon binds to a Unix socket instead of a TCP port. By default that Unix socket is owned by the user root
and other users can access it with sudo
. For this reason, docker
daemon always runs as the root
user.
To avoid having to use sudo
when you use the docker
command, create a Unix group called docker
and add users to it. When the docker
daemon starts, it makes the ownership of the Unix socket read/writable by the docker
group.
Warning: The
docker
group is equivalent to theroot
user; For details on how this impacts security in your system, see Docker Daemon Attack Surface for details.
To create the docker
group and add your user:
Log into Oracle Linux as a user with
sudo
privileges.-
Create the
docker
group.sudo groupadd docker
-
Add your user to
docker
group.sudo usermod -aG docker username
-
Log out and log back in.
This ensures your user is running with the correct permissions.
-
Verify your work by running
docker
withoutsudo
.$ docker run hello-world
If this fails with a message similar to this:
Cannot connect to the Docker daemon. Is 'docker daemon' running on this host?
Check that the
DOCKER_HOST
environment variable is not set for your shell. If it is, unset it.
Configure Docker to start on boot
You can configure the Docker daemon to start automatically at boot.
On Oracle Linux 6:
$ sudo chkconfig docker on
On Oracle Linux 7:
$ sudo systemctl enable docker.service
If you need to add an HTTP Proxy, set a different directory or partition for the Docker runtime files, or make other customizations, read our systemd article to learn how to customize your systemd Docker daemon options.
Use the btrfs storage engine
Docker on Oracle Linux 6 and 7 supports the use of the btrfs storage engine. Before enabling btrfs support, ensure that /var/lib/docker
is stored on a btrfs-based filesystem. Review Chapter 5 of the Oracle Linux Administrator’s Solution Guide for details on how to create and mount btrfs filesystems.
To enable btrfs support on Oracle Linux:
Ensure that
/var/lib/docker
is on a btrfs filesystem.Edit
/etc/sysconfig/docker
and add-s btrfs
to theOTHER_ARGS
field.Restart the Docker daemon:
Uninstallation
To uninstall the Docker package:
$ sudo yum -y remove docker-engine
The above command will not remove images, containers, volumes, or user created configuration files on your host. If you wish to delete all images, containers, and volumes run the following command:
$ rm -rf /var/lib/docker
You must delete the user created configuration files manually.
Known issues
Docker unmounts btrfs filesystem on shutdown
If you’re running Docker using the btrfs storage engine and you stop the Docker service, it will unmount the btrfs filesystem during the shutdown process. You should ensure the filesystem is mounted properly prior to restarting the Docker service.
On Oracle Linux 7, you can use a systemd.mount
definition and modify the Docker systemd.service
to depend on the btrfs mount defined in systemd.
SElinux support on Oracle Linux 7
SElinux must be set to Permissive
or Disabled
in /etc/sysconfig/selinux
to use the btrfs storage engine on Oracle Linux 7.
Further issues?
If you have a current Basic or Premier Support Subscription for Oracle Linux, you can report any issues you have with the installation of Docker via a Service Request at My Oracle Support.
If you do not have an Oracle Linux Support Subscription, you can use the Oracle Linux Forum for community-based support.
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