Installing Docker On Centos

Another popular Linux distribution is CentOS, which is a free, enterprise-class distribution that is compatible with Red Hat Enterprise Linux (RHEL). Go through the following easy recipe to install Docker on CentOS 7.x.

Getting ready

The centos-extra repository must be enabled. This is usually enabled by default, but if you disabled it, please enable it again.

Previously, the Docker package had a different name: It was called docker or docker-engine ; it is now called docker-ce . We will need to remove any previous Docker versions in order to prevent any conflicts:

$ sudo yum remove docker \
    docker-client \
    docker-client-latest \
    docker-common \
    docker-latest \
    docker-latest-logrotate \
    docker-logrotate \
    docker-selinux \
    docker-engine-selinux \
    docker-engine

NOTE

It is OK if yum reports that none of these packages are installed.

How to do it…

Go through the following steps:

  1. Install the required packages:
$ sudo yum install -y yum-utils \
          device-mapper-persistent-data \
          lvm2
  1. Set up the Docker yum repository using the stable channel:
$ sudo yum-config-manager \
          --add-repo \
            https://download.docker.com/linux/centos/docker-ce.repo
  1. Optional : Enable the test channel for access to the nightly builds:
$ sudo yum-config-manager --enable docker-ce-test
  1. Install the latest version of docker-ce :
$ sudo yum install docker-ce
  1. If prompted to accept the GPG key, verify that it matches 060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35 . If it does, then accept it:
Retrieving key from https://download.docker.com/linux/centos/gpg
Importing GPG key 0x621E9F35:
Userid : "Docker Release (CE rpm) <docker@docker.com>"
Fingerprint: 060a 61c5 1b55 8a7f 742b 77aa c52f eb6b 621e 9f35
From : https://download.docker.com/linux/centos/gpg
Is this ok [y/N]: y
  1. Start the Docker daemon:
$ sudo systemctl start docker
  1. Verify that the installation worked:
$ docker container run hello-world

How it works…

The preceding recipe installs Docker on CentOS and all the packages required by it.

There’s more…

The default Docker daemon configuration file is located at /etc/docker , which is used while starting the daemon. Here are some basic operations:

  • To start the service, enter the following:
$ sudo systemctl start docker
  • To verify the installation, enter the following:
$ docker info
  • To update the package, enter the following:
$ sudo yum -y upgrade
  • To enable the service start at boot time, enter the following:
$ sudo systemctl enable docker
  • To uninstall Docker, enter the following:
$ sudo yum remove docker-ce
  • To stop the service, enter the following:
$ sudo systemctl stop docker

See also

For more information, check out the CentOS installation document on the Docker website at https://docs.docker.com/install/linux/docker-ce/centos/.