Docker当前发布的最新版本已经到了1.11，其官网上针对Centos的的安装需求如下:
Docker requires a 64-bit installation regardless of your CentOS version. Also, your kernel must be 3.10 at minimum, which CentOS 7 runs.
看来如果我们想在低于3.x内核的操作系统（比如Centos6.7）上装Docker最新版，势必要升级内核了。且不说升级内核步骤繁琐、容易出错，单就这种比较怪异的搭配：Centos6.x + Kerneol3.X + Docker1.11，就没有人能够保证其稳定性。故我的建议是设法在Centos6.7上安装较低版本的Docker。事实上，对于内核版本要大于3.10这个要求，是从Docker1.8.2版本开始的，Docker之前的版本是可以运行在较低内核版本之上的，比如1.7.1。
首先，看下我的操作环境以及直接安装Docker的现象：
[root@localhost ~]# uname -a Linux localhost.localdomain 2.6.32-573.el6.x86_64 #1 SMP Thu Jul 23 15:44:03 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux [root@localhost ~]# cat /etc/redhat-release CentOS release 6.7 (Final) [root@localhost ~]# docker -bash: docker: command not found [root@localhost ~]# yum install docker Loaded plugins: fastestmirror, refresh-packagekit, security Setting up Install Process base | 3.7 kB 00:00 base/primary_db | 4.6 MB 00:08 extras | 3.4 kB 00:00 extras/primary_db | 37 kB 00:00 updates | 3.4 kB 00:00 updates/primary_db | 5.2 MB 00:55 No package docker available. Error: Nothing to do [root@localhost ~]# yum install docker-io Loaded plugins: fastestmirror, refresh-packagekit, security Setting up Install Process Determining fastest mirrors * base: mirrors.zju.edu.cn * extras: mirrors.skyshe.cn * updates: mirrors.zju.edu.cn No package docker-io available. Error: Nothing to do
可以看到，在Centos6.7的标准yum源中已经没有Docker的安装包了，这时，我们需要安装EPEL。
EPEL（Extra Packages for Enterprise Linux），企业版Linux额外包，RHEL分布非标准包的社区类库。安装如下：
[root@localhost ~]# rpm -iUvh http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm Retrieving http://dl.fedoraproject.org/pub/epel/6/x86_64/epel-release-6-8.noarch.rpm warning: /var/tmp/rpm-tmp.sA7VqQ: Header V3 RSA/SHA256 Signature, key ID 0608b895: NOKEY Preparing... ########################################### [100%] 1:epel-release ########################################### [100%]
接下来安装Docker1.7.1，在1.7.1中，安装包名称为docker-io，故我们的安装命令如下：
[root@localhost ~]# yum install docker-io Loaded plugins: fastestmirror, refresh-packagekit, security Setting up Install Process Loading mirror speeds from cached hostfile epel/metalink | 5.3 kB 00:00 * base: mirrors.zju.edu.cn * epel: ftp.cuhk.edu.hk * extras: mirrors.skyshe.cn * updates: mirrors.zju.edu.cn epel | 4.3 kB 00:00 epel/primary_db | 5.9 MB 00:49 Resolving Dependencies --> Running transaction check ---> Package docker-io.x86_64 0:1.7.1-2.el6 will be installed --> Processing Dependency: lxc for package: docker-io-1.7.1-2.el6.x86_64 --> Processing Dependency: libcgroup for package: docker-io-1.7.1-2.el6.x86_64 --> Running transaction check ---> Package libcgroup.x86_64 0:0.40.rc1-17.el6_7 will be installed ---> Package lxc.x86_64 0:1.0.8-1.el6 will be installed --> Processing Dependency: lua-lxc(x86-64) = 1.0.8-1.el6 for package: lxc-1.0.8-1.el6.x86_64 --> Processing Dependency: lua-alt-getopt for package: lxc-1.0.8-1.el6.x86_64 --> Processing Dependency: liblxc.so.1()(64bit) for package: lxc-1.0.8-1.el6.x86_64 --> Running transaction check ---> Package lua-alt-getopt.noarch 0:0.7.0-1.el6 will be installed ---> Package lua-lxc.x86_64 0:1.0.8-1.el6 will be installed --> Processing Dependency: lua-filesystem for package: lua-lxc-1.0.8-1.el6.x86_64 ---> Package lxc-libs.x86_64 0:1.0.8-1.el6 will be installed --> Running transaction check ---> Package lua-filesystem.x86_64 0:1.4.2-1.el6 will be installed --> Finished Dependency Resolution Dependencies Resolved =================================================================================== Package Arch Version Repository Size =================================================================================== Installing: docker-io x86_64 1.7.1-2.el6 epel 4.6 M Installing for dependencies: libcgroup x86_64 0.40.rc1-17.el6_7 updates 129 k lua-alt-getopt noarch 0.7.0-1.el6 epel 6.9 k lua-filesystem x86_64 1.4.2-1.el6 epel 24 k lua-lxc x86_64 1.0.8-1.el6 epel 16 k lxc x86_64 1.0.8-1.el6 epel 122 k lxc-libs x86_64 1.0.8-1.el6 epel 255 k Transaction Summary ==================================================================================== Install 7 Package(s) Total download size: 5.1 M Installed size: 20 M Is this ok [y/N]: y Downloading Packages: (1/7): docker-io-1.7.1-2.el6.x86_64.rpm | 4.6 MB 01:09 (2/7): libcgroup-0.40.rc1-17.el6_7.x86_64.rpm | 129 kB 00:00 (3/7): lua-alt-getopt-0.7.0-1.el6.noarch.rpm | 6.9 kB 00:00 (4/7): lua-filesystem-1.4.2-1.el6.x86_64.rpm | 24 kB 00:00 (5/7): lua-lxc-1.0.8-1.el6.x86_64.rpm | 16 kB 00:00 (6/7): lxc-1.0.8-1.el6.x86_64.rpm | 122 kB 00:01 (7/7): lxc-libs-1.0.8-1.el6.x86_64.rpm | 255 kB 00:08 ---------------------------------------------------------------------------------------------- Total 64 kB/s | 5.1 MB 01:21 warning: rpmts_HdrFromFdno: Header V3 RSA/SHA256 Signature, key ID 0608b895: NOKEY Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6 Importing GPG key 0x0608B895: Userid : EPEL (6) <epel@fedoraproject.org> Package: epel-release-6-8.noarch (installed) From : /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-6 Is this ok [y/N]: y warning: rpmts_HdrFromFdno: Header V3 RSA/SHA1 Signature, key ID c105b9de: NOKEY Retrieving key from file:///etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 Importing GPG key 0xC105B9DE: Userid : CentOS-6 Key (CentOS 6 Official Signing Key) <centos-6-key@centos.org> Package: centos-release-6-7.el6.centos.12.3.x86_64 (@anaconda-CentOS-201508042137.x86_64/6.7) From : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6 Is this ok [y/N]: y Running rpm_check_debug Running Transaction Test Transaction Test Succeeded Running Transaction Warning: RPMDB altered outside of yum. Installing : lxc-libs-1.0.8-1.el6.x86_64 1/7 Installing : lua-filesystem-1.4.2-1.el6.x86_64 2/7 Installing : lua-lxc-1.0.8-1.el6.x86_64 3/7 Installing : lua-alt-getopt-0.7.0-1.el6.noarch 4/7 Installing : lxc-1.0.8-1.el6.x86_64 5/7 Installing : libcgroup-0.40.rc1-17.el6_7.x86_64 6/7 Installing : docker-io-1.7.1-2.el6.x86_64 7/7 Verifying : lxc-libs-1.0.8-1.el6.x86_64 1/7 Verifying : libcgroup-0.40.rc1-17.el6_7.x86_64 2/7 Verifying : lua-lxc-1.0.8-1.el6.x86_64 3/7 Verifying : lxc-1.0.8-1.el6.x86_64 4/7 Verifying : docker-io-1.7.1-2.el6.x86_64 5/7 Verifying : lua-alt-getopt-0.7.0-1.el6.noarch 6/7 Verifying : lua-filesystem-1.4.2-1.el6.x86_64 7/7 Installed: docker-io.x86_64 0:1.7.1-2.el6 Dependency Installed: libcgroup.x86_64 0:0.40.rc1-17.el6_7 lua-alt-getopt.noarch 0:0.7.0-1.el6 lua-filesystem.x86_64 0:1.4.2-1.el6 lua-lxc.x86_64 0:1.0.8-1.el6 lxc.x86_64 0:1.0.8-1.el6 lxc-libs.x86_64 0:1.0.8-1.el6 Complete! [root@localhost ~]# docker -v Docker version 1.7.1, build 786b29d/1.7.1
安装完成！