CentOS 6.8安装docker报错解决

最近学习docker，在本地虚拟机（Centos版本是7）上安装很顺利。后来想在之前买的阿里云服务器上试试，阿里云的Centos版本是6.8。在安装这一步就被坑了。

一开始按照网上教程，安装步骤如下：

yum -y install http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm
yum install -y docker-io

报错：

Loaded plugins: fastestmirror, refresh-packagekit, security
Setting up Install Process
Loading mirror speeds from cached hostfile
 * base: mirrors.aliyun.com
 * epel: mirrors.tuna.tsinghua.edu.cn
 * extras: mirrors.aliyun.com
 * updates: mirrors.aliyun.com
No package docker-io available.
Error: Nothing to do

换一种方式：
yum install https://get.docker.com/rpm/1.7.1/centos-6/RPMS/x86_64/docker-engine-1.7.1-1.el6.x86_64.rpm

报错信息：

Error: Package: docker-ce-17.03.2.ce-1.el7.centos.x86_64 (docker-ce-stable)
           Requires: libseccomp.so.2()(64bit)
Error: Package: docker-ce-17.03.2.ce-1.el7.centos.x86_64 (docker-ce-stable)
           Requires: libc.so.6(GLIBC_2.17)(64bit)
Error: Package: docker-ce-17.03.2.ce-1.el7.centos.x86_64 (docker-ce-stable)
           Requires: selinux-policy >= 3.13.1-23
           Installed: selinux-policy-3.7.19-307.el6_9.2.noarch (@updates)
               selinux-policy = 3.7.19-307.el6_9.2
           Available: selinux-policy-3.7.19-312.el6.noarch (base)
               selinux-policy = 3.7.19-312.el6
Error: Package: docker-ce-selinux-17.03.2.ce-1.el7.centos.noarch (docker-ce-stable)
           Requires: selinux-policy-targeted >= 3.13.1-102
           Installed: selinux-policy-targeted-3.7.19-307.el6_9.2.noarch (@updates)
               selinux-policy-targeted = 3.7.19-307.el6_9.2
           Available: selinux-policy-targeted-3.7.19-312.el6.noarch (base)
               selinux-policy-targeted = 3.7.19-312.el6
Error: Package: docker-ce-17.03.2.ce-1.el7.centos.x86_64 (docker-ce-stable)
           Requires: libsystemd.so.0()(64bit)
Error: Package: docker-ce-selinux-17.03.2.ce-1.el7.centos.noarch (docker-ce-stable)
           Requires: selinux-policy-base >= 3.13.1-102
           Installed: selinux-policy-targeted-3.7.19-307.el6_9.2.noarch (@updates)
               selinux-policy-base = 3.7.19-307.el6_9.2
           Available: selinux-policy-minimum-3.7.19-312.el6.noarch (base)
               selinux-policy-base = 3.7.19-312.el6
           Available: selinux-policy-mls-3.7.19-312.el6.noarch (base)
               selinux-policy-base = 3.7.19-312.el6
           Available: selinux-policy-targeted-3.7.19-312.el6.noarch (base)
               selinux-policy-base = 3.7.19-312.el6
Error: Package: docker-ce-17.03.2.ce-1.el7.centos.x86_64 (docker-ce-stable)
           Requires: libsystemd.so.0(LIBSYSTEMD_209)(64bit)
Error: Package: docker-ce-17.03.2.ce-1.el7.centos.x86_64 (docker-ce-stable)
           Requires: systemd-units

解决办法：

1. 升级内核
   我没用这个方式，有点麻烦，具体操作可以搜索一下。

2. 删除掉docker-ce.repo
   首先，安装EPEL；

   rpm -Uvh http://download.fedoraproject.org/pub/epel/6/i386/epel-release-6-8.noarch.rpm
   

   然后，打开/etc/yum.repos.d文件夹，删除掉一切docker相关文件，并刷新缓存：

   yum clean all
   yum makecache
   

   最后，安装docker。

   yum install https://get.docker.com/rpm/1.7.1/centos-6/RPMS/x86_64/docker-engine-1.7.1-1.el6.x86_64.rpm
   

   安装成功，启动：
   service docker start

   查看版本：

   [root@iZuf67pk3s****561rer4pZ /]# docker version
   Client version: 1.7.1
   Client API version: 1.19
   Go version (client): go1.4.2
   Git commit (client): 786b29d
   OS/Arch (client): linux/amd64
   Server version: 1.7.1
   Server API version: 1.19
   Go version (server): go1.4.2
   Git commit (server): 786b29d
   OS/Arch (server): linux/amd64
   

好了，大功告成。