Docker Linux Installation

Internal

• Docker

Overview

Verified with Centos 7.

Prerequisites

A 3.8 kernel or later is required.

RedHat/Centos

https://docs.docker.com/install/linux/docker-ce/centos/

The following sequence is based on the document linked above.

Uninstall Old Docker Versions

yum list installed | grep docker

yum erase ...

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

Intall Required yum Utilities

yum install -y yum-utils device-mapper-persistent-data lvm2

Setting a yum Repository

Set up a Docker repository:

yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

This will create /etc/yum.repos.d/docker-ce.repo.

Alternatively, the repository file can be added by hand, in /etc/yum.repos.d, with the following content:

[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/7
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg

Alternative URL for Centos 6: https://yum.dockerproject.org/repo/main/centos/6 Oracle Linux: https://yum.dockerproject.org/repo/main/oraclelinux/6/

This is an example of how to use an "entitled" RH repository:

Using yum with registry.access.redhat.com Images

Restrict Some Releases

yum-config-manager --disable docker-ce-edge
yum-config-manager --disable docker-ce-test

RedHat

Enable the 'extras' Repository

In installed on RedHat, enable the "extras" repository:

yum-config-manager --enable rhel-7-server-extras-rpms

Enable the "ol7" Repository

Add /etc/yum.repos.d/public-yum-ol7.repo with the following content:

[ol7_developer_EPEL]
name=Oracle Linux $releasever Developement Packages ($basearch)
baseurl=http://yum.oracle.com/repo/OracleLinux/OL7/developer_EPEL/$basearch/
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-oracle-ol7
gpgcheck=1
enabled=1

Import the key:

cd /etc/pki/rpm-gpg/
wget http://public-yum.oracle.com/RPM-GPG-KEY-oracle-ol7

Install

yum install docker-ce

Obsolete:

yum install docker-engine

The yum installation procedure enables the docker server to start at boot:

systemctl is-enabled docker
enabled

If not, enable it:

systemctl enable docker

Start

At this point, /var/lib/docker and /etc/docker are not created. To create and initialize:

systemctl start docker

Set Up Storage Backend

devicemapper Storage Setup

For production use on Red Hat, set up devicemapper storage:

devicemapper Installation

Reboot

docker version

Client:
 Version:      17.03.1-ce
 API version:  1.27
 Go version:   go1.7.5
 Git commit:   c6d412e
 Built:        Fri Mar 24 00:36:45 2017
 OS/Arch:      linux/amd64

Server:
 Version:      17.03.1-ce
 API version:  1.27 (minimum version 1.12)
 Go version:   go1.7.5
 Git commit:   c6d412e
 Built:        Fri Mar 24 00:36:45 2017
 OS/Arch:      linux/amd64
 Experimental: false

RedHat/Centos Post-Install

Post-Install

Docker Installation for OpenShift

• Docker Installation for OpenShift 3.6
• Docker Installation for OpenShift 3.5

Ubuntu

Docker installation on Ubuntu is described here, in order:

• https://docs.docker.com/install/linux/docker-ce/ubuntu/
• https://docs.docker.com/install/linux/linux-postinstall/

A summary is available below. The sequence was used to install 18.03.0-ce on Ubuntu 16.04 xenial.

Setup the repository. As root:

 apt-get update
 apt-get install apt-transport-https ca-certificates curl software-properties-common
 curl -fsSL https://download.docker.com/linux/ubuntu/gpg | apt-key add -
 apt-key fingerprint 0EBFCD88
 add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"

Note that $(lsb_release -cs) should return 'xenial' or equivalent. The last command adds the Docker repository in /etc/apt/sources.list.

Install Docker CE. As root:

Update the package index again after setting up the Docker repository:

apt-get update

Then install the latest docker-ce:

apt-get install docker-ce

Test:

docker run hello-world

At this point, docker info may return a warning:

WARNING: No swap limit support

This is addressed by configuring the kernel appropriately. cgroups and swap should be configured in /etc/default/grub, by adding

GRUB_CMDLINE_LINUX="cgroup_enable=memory swapaccount=1"

and then

update-grub
reboot

Start at boot:

systemctl enable docker

Post-Install

Non-root Management Access

Configure a user other than "root" to be able to use the docker client to connect to the server. For details on why we needed to do this see Docker Concepts - Client/Server Communication. The installation procedure should have created the 'docker' group already:

usermod -aG docker <unprivileged-user-to-operate-docker-server>

Test access for unprivileged user. As that user:

docker run hello-world

Inspect storage backend details.

Installation Verification

Docker Installation Verification