DockerをCentOS 7にインストールする方法

CentOS 7ではDockerをフル機能で利用することが可能です。

EPELレポジトリを有効にする

DockerはEPELレポジトリに含まれています。CentOS 7用のEPELレポジトリは現在ベータながら、すでに用意されています。

インストールするコマンドは次の通りです。

$ sudo yum install http://linux.mirrors.es.net/fedora-epel/beta/7/x86_64/epel-release-7-0.2.noarch.rpm

Dockerをインストールする

Dockerのパッケージ名は、docker-ioです。これをyumでインストールします。

$ sudo yum install docker-io

インストールした後に、サービスとして起動させるには systemctl start、ブート時に自動的にサービスを起動させるには systemctl enable を使います。

$ sudo systemctl start docker.service
$ sudo systemctl enable docker.service

これでDockerが利用できる状態になりました。 docker version で確認できます。

$ docker version
Client version: 1.0.0
Client API version: 1.12
Go version (client): go1.2.2
Git commit (client): 63fe64c/1.0.0
Server version: 1.0.0
Server API version: 1.12
Go version (server): go1.2.2
Git commit (server): 63fe64c/1.0.0

また、docker infoで、device mapperを利用していることが確認できます。

$ docker info
Containers: 3
Images: 1
Storage Driver: devicemapper
 Pool Name: docker-253:1-23349-pool
 Data file: /var/lib/docker/devicemapper/devicemapper/data
 Metadata file: /var/lib/docker/devicemapper/devicemapper/metadata
 Data Space Used: 465.8 Mb
 Data Space Total: 102400.0 Mb
 Metadata Space Used: 0.9 Mb
 Metadata Space Total: 2048.0 Mb
Execution Driver: native-0.2
Kernel Version: 3.10.0-123.el7.x86_64

以上で、CentOS 7上でDockerを利用できる状態になりました。

参考: インストールのログ

参考のために、Dockerをインストールした時の進み方を貼り付けておきます。

[yuryu@centos7 ~]$ sudo yum install http://linux.mirrors.es.net/fedora-epel/beta/7/x86_64/epel-release-7-0.2.noarch.rpm
Loaded plugins: fastestmirror
epel-release-7-0.2.noarch.rpm                                                                    |  13 kB  00:00:00     
Examining /var/tmp/yum-root-0OMCgR/epel-release-7-0.2.noarch.rpm: epel-release-7-0.2.noarch
Marking /var/tmp/yum-root-0OMCgR/epel-release-7-0.2.noarch.rpm to be installed
Resolving Dependencies
--> Running transaction check
---> Package epel-release.noarch 0:7-0.2 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

========================================================================================================================
 Package                     Arch                  Version              Repository                                 Size
========================================================================================================================
Installing:
 epel-release                noarch                7-0.2                /epel-release-7-0.2.noarch                 22 k

Transaction Summary
========================================================================================================================
Install  1 Package

Total size: 22 k
Installed size: 22 k
Is this ok [y/d/N]: y
Downloading packages:
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : epel-release-7-0.2.noarch                                                                            1/1 
  Verifying  : epel-release-7-0.2.noarch                                                                            1/1 

Installed:
  epel-release.noarch 0:7-0.2                                                                                           

Complete!
[yuryu@centos7 ~]$ sudo yum install docker-io
Loaded plugins: fastestmirror
base                                                                                             | 3.6 kB  00:00:00     
epel/x86_64/metalink                                                                             |  13 kB  00:00:00     
epel                                                                                             | 3.7 kB  00:00:00     
extras                                                                                           | 2.9 kB  00:00:00     
updates                                                                                          | 2.9 kB  00:00:00     
(1/2): epel/x86_64/group_gz                                                                      | 163 kB  00:00:01     
(2/2): epel/x86_64/primary_db                                                                    | 2.0 MB  00:00:47     
Loading mirror speeds from cached hostfile
 * base: centos-distro.cavecreek.net
 * epel: linux.mirrors.es.net
 * extras: centos-distro.cavecreek.net
 * updates: mirror.supremebytes.com
Resolving Dependencies
--> Running transaction check
---> Package docker-io.x86_64 0:1.0.0-1.el7 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

========================================================================================================================
 Package                      Arch                      Version                           Repository               Size
========================================================================================================================
Installing:
 docker-io                    x86_64                    1.0.0-1.el7                       epel                    4.5 M

Transaction Summary
========================================================================================================================
Install  1 Package

Total download size: 4.5 M
Installed size: 23 M
Is this ok [y/d/N]: y
Downloading packages:
docker-io-1.0.0-1.el7.x86_64.rpm                                                                 | 4.5 MB  00:02:39     
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
  Installing : docker-io-1.0.0-1.el7.x86_64                                                                         1/1 
  Verifying  : docker-io-1.0.0-1.el7.x86_64                                                                         1/1 

Installed:
  docker-io.x86_64 0:1.0.0-1.el7                                                                                        

Complete!
[yuryu@centos7 ~]$ sudo systemctl start docker.service
[yuryu@centos7 ~]$ sudo systemctl enable docker.service
ln -s '/usr/lib/systemd/system/docker.service' '/etc/systemd/system/multi-user.target.wants/docker.service'