docker 1.12是今年docker迄今发布的最为重要的一个版本，它大大增强了docker的内置编排机制。在一直被诟病的集群的构成方面也交出了自己的答卷。虽然增加的功能让你在使用的时候有一种在使用kubernetes的感觉，但这个世界不就是这样么，你有的我也有，我有的是原生态。闲话不说，安装。
| Linux | 版本 |
|---|---|
| CentOS | 7.2 |
设定Yum
docker缺省的Yum库使用的是main，基本上是稳定的版本。目前该版本为1.10。而在centos上安装只需要设定为experimental。将其baseurl设定为https://yum.dockerproject.org/repo/experimental/centos/7/即可。以后升到1.99估计也可以用同样的花招抢先试用吧。以下为设定方式：
cat > /etc/yum.repos.d/docker.repo <<-EOF
[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/experimental/centos/7/
enabled=1
gpgcheck=1
gpgkey=https://yum.dockerproject.org/gpg
EOF确认旧的docker相关的组件并删除
你的机器上一定有用centos简易安装方式yum install docker安装的各种docker组件。安装1.12之前先把它们删掉吧，不然后面有可能还是会提示你删除的。
[root@host32 ~]# rpm -qa |grep docker
docker-selinux-1.10.3-44.el7.centos.x86_64
docker-common-1.10.3-44.el7.centos.x86_64
docker-forward-journald-1.10.3-44.el7.centos.x86_64
docker-1.10.3-44.el7.centos.x86_64
[root@host32 ~]#
[root@host32 ~]# yum -y remove docker-selinux-1.10.3-44.el7.centos.x86_64
[root@host32 ~]# yum -y remove docker-common-1.10.3-44.el7.centos.x86_64
[root@host32 ~]# yum -y remove docker-forward-journald-1.10.3-44.el7.centos.x86_64
[root@host32 ~]# yum -y remove docker-1.10.3-44.el7.centos.x86_64安装docker-engine
安装命令：yum -y install docker-engine
[root@host32 ~]# yum install -y docker-engine
Loaded plugins: fastestmirror, langpacks
dockerrepo | 2.9 kB 00:00:00
dockerrepo/primary_db | 49 kB 00:00:03
Loading mirror speeds from cached hostfile
* base: mirrors.tuna.tsinghua.edu.cn
* epel: mirror.premi.st
* extras: mirrors.tuna.tsinghua.edu.cn
* updates: mirrors.aliyun.com
Resolving Dependencies
--> Running transaction check
---> Package docker-engine.x86_64 0:1.12.0-1.el7.centos will be installed
--> Processing Dependency: docker-engine-selinux >= 1.12.0-1.el7.centos for package: docker-engine-1.12.0-1.el7.centos.x86_64
--> Running transaction check
---> Package docker-engine-selinux.noarch 0:1.12.0-1.el7.centos will be installed
--> Finished Dependency Resolution
Dependencies Resolved
===================================================================================================================================================
Package Arch Version Repository Size
===================================================================================================================================================
Installing:
docker-engine x86_64 1.12.0-1.el7.centos dockerrepo 19 M
Installing for dependencies:
docker-engine-selinux noarch 1.12.0-1.el7.centos dockerrepo 28 k
Transaction Summary
===================================================================================================================================================
Install 1 Package (+1 Dependent package)
Total download size: 19 M
Installed size: 79 M
Downloading packages:
warning: /var/cache/yum/x86_64/7/dockerrepo/packages/docker-engine-selinux-1.12.0-1.el7.centos.noarch.rpm: Header V4 RSA/SHA512 Signature, key ID 2c52609d: NOKEY
Public key for docker-engine-selinux-1.12.0-1.el7.centos.noarch.rpm is not installed
(1/2): docker-engine-selinux-1.12.0-1.el7.centos.noarch.rpm | 28 kB 00:00:02
(2/2): docker-engine-1.12.0-1.el7.centos.x86_64.rpm | 19 MB 00:07:34
---------------------------------------------------------------------------------------------------------------------------------------------------
Total 43 kB/s | 19 MB 00:07:34
Retrieving key from https://yum.dockerproject.org/gpg
Importing GPG key 0x2C52609D:
Userid : "Docker Release Tool (releasedocker) <docker@docker.com>"
Fingerprint: 5811 8e89 f3a9 1289 7c07 0adb f762 2157 2c52 609d
From : https://yum.dockerproject.org/gpg
Running transaction check
Running transaction test
Transaction test succeeded
Running transaction
Installing : docker-engine-selinux-1.12.0-1.el7.centos.noarch 1/2
Installing : docker-engine-1.12.0-1.el7.centos.x86_64 2/2
Verifying : docker-engine-selinux-1.12.0-1.el7.centos.noarch 1/2
Verifying : docker-engine-1.12.0-1.el7.centos.x86_64 2/2
Installed:
docker-engine.x86_64 0:1.12.0-1.el7.centos
Dependency Installed:
docker-engine-selinux.noarch 0:1.12.0-1.el7.centos
Complete!
[root@host32 ~]#设定自启动
命令：systemctl enable docker
启动docker服务
命令：systemctl start docker
确认docker版本
命令：docker info
确认server version为1.12
[root@host32 ~]# docker info
Containers: 1
Running: 0
Paused: 0
Stopped: 1
Images: 3
Server Version: 1.12.0
Storage Driver: devicemapper
Pool Name: docker-253:0-19943542-pool
Pool Blocksize: 65.54 kB
Base Device Size: 10.74 GB
Backing Filesystem: xfs
Data file: /dev/loop0
Metadata file: /dev/loop1
Data Space Used: 2.443 GB
Data Space Total: 107.4 GB
Data Space Available: 1.789 GB
Metadata Space Used: 3.568 MB
Metadata Space Total: 2.147 GB
Metadata Space Available: 1.789 GB
Thin Pool Minimum Free Space: 10.74 GB
Udev Sync Supported: true
Deferred Removal Enabled: false
Deferred Deletion Enabled: false
Deferred Deleted Device Count: 0
Data loop file: /var/lib/docker/devicemapper/devicemapper/data
WARNING: Usage of loopback devices is strongly discouraged for production use. Use `--storage-opt dm.thinpooldev` to specify a custom block storage device.
Metadata loop file: /var/lib/docker/devicemapper/devicemapper/metadata
Library Version: 1.02.107-RHEL7 (2015-10-14)
Logging Driver: json-file
Cgroup Driver: cgroupfs
Plugins:
Volume: local
Network: bridge null host overlay
Swarm: inactive
Runtimes: runc
Default Runtime: runc
Security Options: seccomp
Kernel Version: 3.10.0-327.el7.x86_64
Operating System: CentOS Linux 7 (Core)
OSType: linux
Architecture: x86_64
CPUs: 1
Total Memory: 1.939 GiB
Name: host32
ID: F5ZC:SZXG:H3MC:3UHT:N3K3:XLYQ:IC6I:ZQN5:2TPK:T7RT:AIJB:Z3IM
Docker Root Dir: /var/lib/docker
Debug Mode (client): false
Debug Mode (server): false
Registry: https://index.docker.io/v1/
WARNING: bridge-nf-call-ip6tables is disabled
Experimental: true
Insecure Registries:
127.0.0.0/8
[root@host32 ~]#