CentOS6.6内核升级,安装docker17.06.2-ce

前言

---

由于笔者所在公司无论是开发、测试环境，还是准生产环境、生产环境，使用的都是CentOS6.6。要想按照新版本的Docker就必须升级Linux内核。因此，此文讲解如何升级Linux内核，以及在升级完内核后，如何安装Docker17.06.2-ce。其他版本的docker笔者没有尝试，应该也是可行的。毕竟内核升级到4.4.132-1了

安装方式一

第一种安装方式，需要联网，因此请确保机器可以连接到互联网

升级Linux内核

• 查看当前linux内核版本,查看CentOS版本

uname -a

cat /etc/centos-release

[root@localhost ~]# uname -a
Linux localhost.localdomain 2.6.32-504.el6.x86_64 #1 SMP Wed Oct 15 04:27:16 UTC 2014 x86_64 x86_64 x86_64 GNU/Linux
[root@localhost ~]# cat /etc/centos-release 
CentOS release 6.6 (Final)

• 导入存储库的GPG密钥

rpm –import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

[root@localhost ~]# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
curl: (35) SSL connect error
error: https://www.elrepo.org/RPM-GPG-KEY-elrepo.org: import read failed(2).

• 若你也遇到以上错误，可执行下yum -y update nss

yum -y update nss

[root@localhost ~]# yum -y update nss
Loaded plugins: fastestmirror
Setting up Update Process
base                                                                                                                                                                    | 3.7 kB     00:00     
base/primary_db                                                                                                                                                         | 4.7 MB     00:01     
extras                                                                                                                                                                  | 3.4 kB     00:00     
extras/primary_db                                                                                                                                                       |  30 kB     00:00     
updates                                                                                                                                                                 | 3.4 kB     00:00     
updates/primary_db                                                                                                                                                      | 8.1 MB     00:03     
Resolving Dependencies
--> Running transaction check
---> Package nss.x86_64 0:3.16.1-14.el6 will be updated
--> Processing Dependency: nss = 3.16.1-14.el6 for package: nss-sysinit-3.16.1-14.el6.x86_64
--> Processing Dependency: nss(x86-64) = 3.16.1-14.el6 for package: nss-tools-3.16.1-14.el6.x86_64
---> Package nss.x86_64 0:3.28.4-4.el6_9 will be an update
--> Processing Dependency: nss-util >= 3.28.3 for package: nss-3.28.4-4.el6_9.x86_64
--> Processing Dependency: nss-softokn(x86-64) >= 3.14.3-22 for package: nss-3.28.4-4.el6_9.x86_64
--> Processing Dependency: nspr >= 4.13.0 for package: nss-3.28.4-4.el6_9.x86_64
--> Processing Dependency: libnssutil3.so(NSSUTIL_3.24)(64bit) for package: nss-3.28.4-4.el6_9.x86_64
--> Processing Dependency: libnssutil3.so(NSSUTIL_3.21)(64bit) for package: nss-3.28.4-4.el6_9.x86_64
--> Running transaction check
---> Package nspr.x86_64 0:4.10.6-1.el6_5 will be updated
---> Package nspr.x86_64 0:4.13.1-1.el6 will be an update
---> Package nss-softokn.x86_64 0:3.14.3-17.el6 will be updated
---> Package nss-softokn.x86_64 0:3.14.3-23.3.el6_8 will be an update
--> Processing Dependency: nss-softokn-freebl(x86-64) >= 3.14.3-23.3.el6_8 for package: nss-softokn-3.14.3-23.3.el6_8.x86_64
---> Package nss-sysinit.x86_64 0:3.16.1-14.el6 will be updated
---> Package nss-sysinit.x86_64 0:3.28.4-4.el6_9 will be an update
---> Package nss-tools.x86_64 0:3.16.1-14.el6 will be updated
---> Package nss-tools.x86_64 0:3.28.4-4.el6_9 will be an update
---> Package nss-util.x86_64 0:3.16.1-3.el6 will be updated
---> Package nss-util.x86_64 0:3.28.4-1.el6_9 will be an update
--> Running transaction check
---> Package nss-softokn-freebl.x86_64 0:3.14.3-17.el6 will be updated
---> Package nss-softokn-freebl.x86_64 0:3.14.3-23.3.el6_8 will be an update
--> Finished Dependency Resolution

Dependencies Resolved

===============================================================================================================================================================================================
 Package                                             Arch                                    Version                                            Repository                                Size
===============================================================================================================================================================================================
Updating:
 nss                                                 x86_64                                  3.28.4-4.el6_9                                     updates                                  879 k
Updating for dependencies:
 nspr                                                x86_64                                  4.13.1-1.el6                                       base                                     114 k
 nss-softokn                                         x86_64                                  3.14.3-23.3.el6_8                                  base                                     262 k
 nss-softokn-freebl                                  x86_64                                  3.14.3-23.3.el6_8                                  base                                     168 k
 nss-sysinit                                         x86_64                                  3.28.4-4.el6_9                                     updates                                   51 k
 nss-tools                                           x86_64                                  3.28.4-4.el6_9                                     updates                                  447 k
 nss-util                                            x86_64                                  3.28.4-1.el6_9                                     updates                                   68 k

Transaction Summary
===============================================================================================================================================================================================
Upgrade       7 Package(s)

Total download size: 1.9 M
Downloading Packages:
(1/7): nspr-4.13.1-1.el6.x86_64.rpm                                                                                                                                     | 114 kB     00:00     
(2/7): nss-3.28.4-4.el6_9.x86_64.rpm                                                                                                                                    | 879 kB     00:00     
(3/7): nss-softokn-3.14.3-23.3.el6_8.x86_64.rpm                                                                                                                         | 262 kB     00:00     
(4/7): nss-softokn-freebl-3.14.3-23.3.el6_8.x86_64.rpm                                                                                                                  | 168 kB     00:00     
(5/7): nss-sysinit-3.28.4-4.el6_9.x86_64.rpm                                                                                                                            |  51 kB     00:00     
(6/7): nss-tools-3.28.4-4.el6_9.x86_64.rpm                                                                                                                              | 447 kB     00:00     
(7/7): nss-util-3.28.4-1.el6_9.x86_64.rpm                                                                                                                               |  68 kB     00:00     
-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Total                                                                                                                                                          986 kB/s | 1.9 MB     00:02     
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-6-6.el6.centos.12.2.x86_64 (@anaconda-CentOS-201410241409.x86_64/6.6)
 From   : /etc/pki/rpm-gpg/RPM-GPG-KEY-CentOS-6
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Updating   : nspr-4.13.1-1.el6.x86_64                                                                                                                                                   1/14 
  Updating   : nss-util-3.28.4-1.el6_9.x86_64                                                                                                                                             2/14 
  Updating   : nss-softokn-freebl-3.14.3-23.3.el6_8.x86_64                                                                                                                                3/14 
  Updating   : nss-softokn-3.14.3-23.3.el6_8.x86_64                                                                                                                                       4/14 
  Updating   : nss-sysinit-3.28.4-4.el6_9.x86_64                                                                                                                                          5/14 
  Updating   : nss-3.28.4-4.el6_9.x86_64                                                                                                                                                  6/14 
  Updating   : nss-tools-3.28.4-4.el6_9.x86_64                                                                                                                                            7/14 
  Cleanup    : nss-tools-3.16.1-14.el6.x86_64                                                                                                                                             8/14 
  Cleanup    : nss-sysinit-3.16.1-14.el6.x86_64                                                                                                                                           9/14 
  Cleanup    : nss-3.16.1-14.el6.x86_64                                                                                                                                                  10/14 
  Cleanup    : nss-softokn-3.14.3-17.el6.x86_64                                                                                                                                          11/14 
  Cleanup    : nss-util-3.16.1-3.el6.x86_64                                                                                                                                              12/14 
  Cleanup    : nspr-4.10.6-1.el6_5.x86_64                                                                                                                                                13/14 
  Cleanup    : nss-softokn-freebl-3.14.3-17.el6.x86_64                                                                                                                                   14/14 
  Verifying  : nss-tools-3.28.4-4.el6_9.x86_64                                                                                                                                            1/14 
  Verifying  : nss-3.28.4-4.el6_9.x86_64                                                                                                                                                  2/14 
  Verifying  : nss-softokn-3.14.3-23.3.el6_8.x86_64                                                                                                                                       3/14 
  Verifying  : nss-softokn-freebl-3.14.3-23.3.el6_8.x86_64                                                                                                                                4/14 
  Verifying  : nspr-4.13.1-1.el6.x86_64                                                                                                                                                   5/14 
  Verifying  : nss-util-3.28.4-1.el6_9.x86_64                                                                                                                                             6/14 
  Verifying  : nss-sysinit-3.28.4-4.el6_9.x86_64                                                                                                                                          7/14 
  Verifying  : nss-sysinit-3.16.1-14.el6.x86_64                                                                                                                                           8/14 
  Verifying  : nspr-4.10.6-1.el6_5.x86_64                                                                                                                                                 9/14 
  Verifying  : nss-softokn-3.14.3-17.el6.x86_64                                                                                                                                          10/14 
  Verifying  : nss-util-3.16.1-3.el6.x86_64                                                                                                                                              11/14 
  Verifying  : nss-3.16.1-14.el6.x86_64                                                                                                                                                  12/14 
  Verifying  : nss-softokn-freebl-3.14.3-17.el6.x86_64                                                                                                                                   13/14 
  Verifying  : nss-tools-3.16.1-14.el6.x86_64                                                                                                                                            14/14 

Updated:
  nss.x86_64 0:3.28.4-4.el6_9                                                                                                                                                                  

Dependency Updated:
  nspr.x86_64 0:4.13.1-1.el6       nss-softokn.x86_64 0:3.14.3-23.3.el6_8 nss-softokn-freebl.x86_64 0:3.14.3-23.3.el6_8 nss-sysinit.x86_64 0:3.28.4-4.el6_9 nss-tools.x86_64 0:3.28.4-4.el6_9
  nss-util.x86_64 0:3.28.4-1.el6_9

Complete!

• 再次尝试导入GPG密钥就OK了

rpm –import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org

[root@localhost ~]# rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
[root@localhost ~]#

• 安装ELRepo

rpm -Uvh http://www.elrepo.org/elrepo-release-6-8.el6.elrepo.noarch.rpm

[root@localhost ~]# rpm -Uvh http://www.elrepo.org/elrepo-release-6-8.el6.elrepo.noarch.rpm
Retrieving http://www.elrepo.org/elrepo-release-6-8.el6.elrepo.noarch.rpm
Preparing...                ########################################### [100%]
   1:elrepo-release         ########################################### [100%]

• 安装新内核

yum –enablerepo=elrepo-kernel install kernel-lt -y

不建议 yum –enablerepo=elrepo-kernel install -y kernel-ml（ ml=mainline）

[root@localhost ~]# yum --enablerepo=elrepo-kernel install kernel-lt -y
Loaded plugins: fastestmirror
Setting up Install Process
Determining fastest mirrors
 * base: mirrors.aliyun.com
 * elrepo: mirrors.tuna.tsinghua.edu.cn
 * elrepo-kernel: mirrors.tuna.tsinghua.edu.cn
 * extras: mirrors.aliyun.com
 * updates: centos.ustc.edu.cn
elrepo                                                                                                                                                                  | 2.9 kB     00:00     
elrepo/primary_db                                                                                                                                                       | 718 kB     00:00     
elrepo-kernel                                                                                                                                                           | 2.9 kB     00:00     
elrepo-kernel/primary_db                                                                                                                                                |  22 kB     00:00     
Resolving Dependencies
--> Running transaction check
---> Package kernel-lt.x86_64 0:4.4.132-1.el6.elrepo will be installed
--> Finished Dependency Resolution

Dependencies Resolved

===============================================================================================================================================================================================
 Package                                    Arch                                    Version                                               Repository                                      Size
===============================================================================================================================================================================================
Installing:
 kernel-lt                                  x86_64                                  4.4.132-1.el6.elrepo                                  elrepo-kernel                                   39 M

Transaction Summary
===============================================================================================================================================================================================
Install       1 Package(s)

Total download size: 39 M
Installed size: 178 M
Downloading Packages:
kernel-lt-4.4.132-1.el6.elrepo.x86_64.rpm                                                                                                                               |  39 MB     00:11     
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
Warning: RPMDB altered outside of yum.
  Installing : kernel-lt-4.4.132-1.el6.elrepo.x86_64                                                                                                                                       1/1 
  Verifying  : kernel-lt-4.4.132-1.el6.elrepo.x86_64                                                                                                                                       1/1 

Installed:
  kernel-lt.x86_64 0:4.4.132-1.el6.elrepo                                                                                                                                                      

Complete!

• 编辑grub.conf文件，修改Grub引导顺序

vi /etc/grub.conf (这里踩了个坑，我改了/etc/grub.conf文件，但是貌似一直没有生效，后来发现原来用的是/boot/grub/grub.conf，这个得事先观察下是否存在这个/boot/grub/grub.conf)，一般情况应该都是使用/etc/grub.conf。但无论如何安装内核都是去操作/etc/grub.conf文件的，如果grub启动用的是/boot/grub/grub.conf，那么请将/etc/grub.conf文件内新安装的内核的启动引导配置复制到/boot/grub/grub.conf文件内。

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE:  You have a /boot partition.  This means that
#          all kernel and initrd paths are relative to /boot/, eg.
#          root (hd0,0)
#          kernel /vmlinuz-version ro root=/dev/mapper/VolGroup-LogVol00
#          initrd /initrd-[generic-]version.img
#boot=/dev/sda
default=0
timeout=5
splashimage=(hd0,0)/grub/splash.xpm.gz
hiddenmenu
title CentOS (4.4.132-1.el6.elrepo.x86_64)
        root (hd0,0)
        kernel /vmlinuz-4.4.132-1.el6.elrepo.x86_64 ro root=/dev/mapper/VolGroup-LogVol00 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=us rd_LVM_LV=VolGroup/LogVol00 rd_NO_DM rhgb quiet
        initrd /initramfs-4.4.132-1.el6.elrepo.x86_64.img
title CentOS 6 (2.6.32-504.el6.x86_64)
        root (hd0,0)
        kernel /vmlinuz-2.6.32-504.el6.x86_64 ro root=/dev/mapper/VolGroup-LogVol00 rd_NO_LUKS LANG=en_US.UTF-8 rd_NO_MD SYSFONT=latarcyrheb-sun16 crashkernel=auto  KEYBOARDTYPE=pc KEYTABLE=us rd_LVM_LV=VolGroup/LogVol00 rd_NO_DM rhgb quiet
        initrd /initramfs-2.6.32-504.el6.x86_64.img

将default=1改为default=0,确保默认启动新的内核。一般新安装的内核会在第一个位置(从0开始)，所以设置default=0

安装Docker

笔者这里用的是二进制安装包来安装

• 下载安装，配置国内中科大docker镜像源

下面给出中科大与阿里云的docker二进制安装包

curl -O http://mirrors.ustc.edu.cn/docker-ce/linux/static/stable/x86_64/docker-17.06.2-ce.tgz

tar -xzvf docker-17.06.2-ce.tgz && cp docker/* /usr/bin && rm -rf docker

mkdir -p /etc/docker && echo “{\”registry-mirrors\”: [\”https://docker.mirrors.ustc.edu.cn\”]}” > /etc/docker/daemon.json

[root@localhost ~]# curl -O http://mirrors.ustc.edu.cn/docker-ce/linux/static/stable/x86_64/docker-17.06.2-ce.tgz
  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100 28.3M  100 28.3M    0     0  3618k      0  0:00:08  0:00:08 --:--:-- 3726k
[root@localhost ~]# ll
total 29032
-rw-------. 1 root root     1038 May 22 20:46 anaconda-ks.cfg
-rw-r--r--. 1 root root 29704322 May 24 23:46 docker-17.06.2-ce.tgz
-rw-r--r--. 1 root root     8823 May 22 20:46 install.log
-rw-r--r--. 1 root root     3384 May 22 20:45 install.log.syslog
[root@localhost ~]# tar -xzvf docker-17.06.2-ce.tgz && cp docker/* /usr/bin && rm -rf docker
docker/
docker/docker-runc
docker/docker
docker/docker-containerd-ctr
docker/docker-containerd
docker/docker-proxy
docker/docker-containerd-shim
docker/dockerd
docker/docker-init

[root@localhost ~]# mkdir -p /etc/docker && echo "{\"registry-mirrors\": [\"https://docker.mirrors.ustc.edu.cn\"]}" > /etc/docker/daemon.json
[root@localhost ~]# ls /etc/docker/
daemon.json  key.json

• 如果我们此时启动dockerd，提示我们升级到3.10.0内核版本或升级到更新的内核版本，这个重启下就好了，不用担心

[root@localhost ~]# dockerd 
WARN[0000] could not change group /var/run/docker.sock to docker: group docker not found 
WARN[0000] libcontainerd: makeUpgradeProof could not open /var/run/docker/libcontainerd/containerd 
INFO[0000] libcontainerd: new containerd process, pid: 13659 
WARN[0000] containerd: low RLIMIT_NOFILE changing to max  current=1024 max=4096
FATA[0001] Your Linux kernel version 2.6.32-504.el6.x86_64 is not supported for running docker. Please upgrade your kernel to 3.10.0 or newer.

• 给dockerd设置自动启动

echo “nohup dockerd > /var/log/dockerd.log & 2>&1” >> /etc/rc.local

[root@localhost ~]# echo "nohup dockerd > /var/log/dockerd.log 2>&1 &" >> /etc/rc.local
[root@localhost ~]#

• 重启查看内核版本

如果看到内核版本已经是4.4.132啦，那说明grub确实已经引导了新的内核了

[root@localhost ~]# uname -a
Linux localhost.localdomain 4.4.132-1.el6.elrepo.x86_64 #1 SMP Wed May 16 14:20:29 EDT 2018 x86_64 x86_64 x86_64 GNU/Linux

• 查看docker info但提示docker没启动成功

此时我们也可以查看docker的日志，我们把日志放在了/var/log/dockerd.log。或者你可以直接运行dockerd。

提示我们cgroup的东东，看来得安装cgroup

[root@localhost ~]# docker info
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?

[root@localhost ~]# dockerd 
WARN[0000] could not change group /var/run/docker.sock to docker: group docker not found 
INFO[0000] libcontainerd: new containerd process, pid: 1293 
WARN[0000] containerd: low RLIMIT_NOFILE changing to max  current=1024 max=4096
INFO[0001] [graphdriver] using prior storage driver: overlay2 
INFO[0001] Graph migration to content-addressability took 0.00 seconds 
WARN[0001] Your kernel does not support cgroup memory limit 
WARN[0001] Unable to find cpu cgroup in mounts          
WARN[0001] Unable to find blkio cgroup in mounts        
WARN[0001] Unable to find cpuset cgroup in mounts       
WARN[0001] mountpoint for pids not found                
Error starting daemon: Devices cgroup isn't mounted

• 安装cgroup,并配置挂载cgroup，需要重启系统(当然这一步可以在之前重启前就做好，这样系统只要重启一次就好了，我这里只是想分享我的踩坑经历哈，就按我踩坑的顺序写下去了)

yum install -y libcgroup

echo “none /sys/fs/cgroup cgroup defaults 0 0” >> /etc/fstab

[root@localhost ~]# yum install -y libcgroup
Loaded plugins: fastestmirror
Setting up Install Process
Loading mirror speeds from cached hostfile
 * base: mirrors.aliyun.com
 * elrepo: mirrors.tuna.tsinghua.edu.cn
 * extras: mirrors.aliyun.com
 * updates: centos.ustc.edu.cn
Resolving Dependencies
--> Running transaction check
---> Package libcgroup.x86_64 0:0.40.rc1-24.el6_9 will be installed
--> Finished Dependency Resolution

Dependencies Resolved

===============================================================================================================================================================================================
 Package                                      Arch                                      Version                                               Repository                                  Size
===============================================================================================================================================================================================
Installing:
 libcgroup                                    x86_64                                    0.40.rc1-24.el6_9                                     updates                                    131 k

Transaction Summary
===============================================================================================================================================================================================
Install       1 Package(s)

Total download size: 131 k
Installed size: 331 k
Downloading Packages:
libcgroup-0.40.rc1-24.el6_9.x86_64.rpm                                                                                                                                  | 131 kB     00:00     
Running rpm_check_debug
Running Transaction Test
Transaction Test Succeeded
Running Transaction
  Installing : libcgroup-0.40.rc1-24.el6_9.x86_64                                                                                                                                          1/1 
  Verifying  : libcgroup-0.40.rc1-24.el6_9.x86_64                                                                                                                                          1/1 

Installed:
  libcgroup.x86_64 0:0.40.rc1-24.el6_9                                                                                                                                                         

Complete!

[root@localhost ~]# echo "none                    /sys/fs/cgroup         cgroup   defaults        0 0" >> /etc/fstab
[root@localhost ~]#

一键安装shell脚本

上述一步步比较多，可以整合在一起搞一个shell进行统一处理，因此有了下面的一键安装脚本

笔者希望在别的机器上能一键处理，自己写了个一键安装内核及docker的脚本。这里仅供给大家参考，但由于笔者水平有限，不可能写出非常完美的安装脚本，并不保证在每台机器上都能完美运行。也希望大家多多提建议，我可以改进这个脚本。

curl也可以用来下载如curl -O http://mirrors.ustc.edu.cn/docker-ce/linux/static/stable/x86_64/docker-17.06.2-ce.tgz

#!/bin/sh

# 必须要以root帐号或sudo来运行
wget_bin=`which wget`
if [ -z "$wget_bin" ];then
  echo "please install wget" >&2
  exit 1
fi
# 禁用 fastestmirror 插件
sed -i.backup 's/^enabled=1/enabled=0/' /etc/yum/pluginconf.d/fastestmirror.conf
# 备份
mv /etc/yum.repos.d/CentOS-Base.repo /etc/yum.repos.d/CentOS-Base.repo.backup
# 使用阿里云镜像
wget -O /etc/yum.repos.d/CentOS-Base-aliyun.repo http://mirrors.aliyun.com/repo/Centos-6.repo
# 安装 EPEL 源(用于更新内核)
elrepo="/etc/yum.repos.d/elrepo.repo"
if [ ! -f $elrepo ]; then
  yum -y update nss
  rpm --import https://www.elrepo.org/RPM-GPG-KEY-elrepo.org
  rpm -Uvh http://www.elrepo.org/elrepo-release-6-8.el6.elrepo.noarch.rpm
fi

# 使用阿里云镜像
if [[ ! -f /etc/yum.repos.d/epel.repo.backup ]]; then
  mv /etc/yum.repos.d/epel.repo /etc/yum.repos.d/epel.repo.backup 2>/dev/null || :
fi
if [[ ! -f /etc/yum.repos.d/epel-testing.repo.backup ]]; then
  mv /etc/yum.repos.d/epel-testing.repo /etc/yum.repos.d/epel-testing.repo.backup 2>/dev/null || :
fi
wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel.repo
wget -O /etc/yum.repos.d/epel-testing.repo http://mirrors.aliyun.com/repo/epel-testing.repo
yum clean all
yum makecache

# 安装cgroup，docker依赖它
if [ ! -d "/sys/fs/cgroup" ]; then
  yum install -y libcgroup
fi
count=`cat /etc/fstab |grep "/sys/fs/cgroup"|grep -v grep |wc -l`
if [ $count -eq 0 ]; then
   echo "none                    /sys/fs/cgroup         cgroup   defaults        0 0" >> /etc/fstab
fi

# 找出4.4内核的启动顺序，并自动修改/etc/grub.conf(这里有坑如果是grub配置文件用的是/boot/grub/grub.conf请自行修改)
count=`cat /etc/grub.conf |grep "/vmlinuz-4.4.*" |grep -v grep |wc -l`
if [ $count -eq 0 ]; then
  yum --enablerepo=elrepo-kernel install kernel-lt -y
 content=`cat /etc/grub.conf |grep title`
 target_kernel=4.4
 num=0
 target=0
 while read line
   do
        echo $line
        if [[ "$line" == *"$target_kernel"* ]]; then
          target=$num
        fi
        let num=num+1
  done <<< "$content"
  sed -i 's/^default\s*=\s*[0-9]/default=$target/g' /etc/grub.conf
fi

sed -i 's/^net\.ipv4\.ip_forward\s*=\s*[0-1]/net\.ipv4\.ip_forward = 1/g' /etc/sysctl.conf
# 仅仅是为了消除dockerd启动时的警告日志
echo "CentOS release 6.x (Final)" > /usr/lib/os-release

# 压轴了，安装docker
dockerd_bin=`which dockerd`
if [ -z "$dockerd_bin" ]; then
  if [ ! -f "docker-17.06.2-ce.tgz" ]; then
    wget http://mirrors.ustc.edu.cn/docker-ce/linux/static/stable/x86_64/docker-17.06.2-ce.tgz
    tar -xzvf docker-17.06.2-ce.tgz && cp docker/* /usr/bin && rm -rf docker
    count=`cat /etc/rc.local |grep dockerd | grep -v grep | wc -l`
    if [ $count -eq 0 ]; then
       echo "nohup dockerd > /var/log/dockerd.log 2>&1 &" >> /etc/rc.local
    fi
  fi
fi

if [ ! -d "/etc/docker" ]; then
  mkdir -p /etc/docker
fi

docker_daemon_file="/etc/docker/daemon.json"
if [ ! -f $docker_daemon_file ]; then
  echo "{\"registry-mirrors\": [\"https://docker.mirrors.ustc.edu.cn\"]}" > /etc/docker/daemon.json
fi

执行完记得要重启机器

安装方式二

---

为什么有安装方式二？这个说来话长，公司内部有几台服务器无法连接外网，只能先下载好安装包。这个我就写简单点了哈。
| 安装包名 | 下载地址 |
| ———————— | ———————————————————— |
| linux4.4.132-1内核安装包 | http://elrepo.org/linux/kernel/el6/x86_64/RPMS/kernel-lt-4.4.132-1.el6.elrepo.x86_64.rpm |
| cgroup安装包 | http://mirror.centos.org/centos/6/updates/x86_64/Packages/libcgroup-0.40.rc1-24.el6_9.x86_64.rpm |
| docker安装包 | http://mirrors.ustc.edu.cn/docker-ce/linux/static/stable/x86_64/docker-17.06.2-ce.tgz |

• 离线安装内核及cgroup

rpm -ivh kernel-lt-4.4.132-1.el6.elrepo.x86_64.rpm

rpm -ivh libcgroup-0.40.rc1-24.el6_9.x86_64.rpm

• 挂载cgroup文件系统

echo "none                    /sys/fs/cgroup         cgroup   defaults        0 0" >> /etc/fstab

• 修改grub内核启动顺序

vi /etc/grub.conf(这里有坑，可能会用/boot/grub/grub.conf)

得确定下是否存在 /boot/grub/grub.conf如果存在那么 grub启动用的是这个文件如果不存在用的是/etc/grub.conf安装完内核后，默认会在/etc/grub.conf下添加一条记录把/etc/grub.conf下的添加的新内核的启动记录复制到/boot/grub/grub.conf文件末尾，然后把/boot/grub/grub.conf的 default=0改为default=1

• 安装docker

tar -xzvf  docker-17.06.2-ce.tgz && cp docker/* /usr/bin && rm -rf docker

• 配置使用国内中科大的镜像

mkdir -p /etc/docker 
echo -e "{\n\t\"registry-mirrors\": [\"https://docker.mirrors.ustc.edu.cn\"]\n}" > /etc/docker/daemon.json

• 设置dockerd自动启动

echo "nohup dockerd > /var/log/dockerd.log 2>&1 &" >> /etc/rc.local

• 重启

reboot 

或

shutdown -r now

附加注意点

---

几个常见警告的解决

• IPv4 forwarding is disabled的警告

vi /etc/sysctl.conf

# Controls IP packet forwarding
net.ipv4.ip_forward = 1
其他配置省略...

• Could not get operating system name: Error opening /usr/lib/os-release: open /usr/lib/os-release: no such file or directory

echo “CentOS release 6.x (Final)” | tee /usr/lib/os-release

[root@localhost ~]# echo "CentOS release 6.x (Final)" | tee  /usr/lib/os-release
CentOS release 6.x (Final)

docker exec -it 报错的问题

报的错误是rpc error: code = 2 desc = oci runtime error: exec failed: container_linux.go:262: starting container process caused “open /dev/ptmx: no such file or directory “，我看了下宿主机上是有这个文件，那么应该是容器里没有的原因，目前还没查到原因。不过可以通过启动容器时指定 -v /dev:/dev 映射宿主机/dev来解决

此问题可以在启动容器的时候时候，通过-v /dev:/dev来解决，如：

docker run -it -d --name mynginx -p 80:80  -v /dev:/dev nginx:alpine
docker run -it -d --name myjdk -v /dev:/dev openjdk:8-jdk-alpine

如果报以下错误则可以执行下yum update

[root@centos ~]# docker run -it alpine:3.7 /bin/sh
Unable to find image ‘alpine:3.7’ locally
3.7: Pulling from library/alpine
ff3a5c916c92: Pull complete
Digest: sha256:e1871801d30885a610511c867de0d6baca7ed4e6a2573d506bbec7fd3b03873f
Status: Downloaded newer image for alpine:3.7
docker: Error response from daemon: mkdir /var/lib/docker/overlay2/3520bc6c5dcc7ba4dc5e2ba1419cd6250c4b6d61797da7487f20d991179ddd05-init/merged/dev/shm: permission denied.
See ‘docker run –help’.

那么请yum update下，注意/etc/grub.conf的内核启动顺序，要改下

提供一个service脚本

可以方便的实现 service dockerd start,service dockerd stop，service dockerd restart

创建一个dockerd文件，赋予可执行权限,并将该文件放到/etc/init.d即可

#!/bin/sh
#set -x
BASE_HOME=/var/run
PID_FILE=$BASE_HOME/docker.pid

# dockerd父进程的id,如果docker.pid文件不存在则PID值就为-1
PID=-1
if [ -f $PID_FILE ];then
  PID=`cat $PID_FILE`
fi


status(){
    if [ $PID -gt -1 ]; then
       echo "dockerd is running"        
    else
       echo "dockerd is not running"        
    fi
}

start() {
    if [ $PID -gt -1 ]; then
       echo "dockerd has started,the pid is $PID"
       return
    fi
    nohup dockerd > /var/log/dockerd.log 2>&1 &
    COUNT=0
    NUMBER=0
    echo -e "starting...\c"
    while [ $COUNT -lt 2 ]; do
      echo -e ".\c"
      sleep 0.25
      if [ -f $PID_FILE ];then
         PID=`cat $PID_FILE`
      fi
      COUNT=`ps -ef |grep $PID|grep -v grep|wc -l`
      # dockerd父进程与docker-containerd子进程都启动
      if [ $COUNT -ge 2 ]; then
         echo -e "\ndockerd has started,the pid is $PID"
         return
      fi
      if [ $NUMBER -gt 20 ]; then
         break
      fi
      NUMBER=$NUMBER+1
    done
    
    echo -e "\ndockerd start failed"        
}

stop() {
   if [ $PID -eq -1 ]; then
    echo "dockerd is not running"
    return
   fi
   
   # PIDS得到的是dockerd父进程及docker-containerd子进程号
   # sort -r是为了先杀子进程，再杀父进程
   PIDS=`ps -ef|grep $PID|grep -v grep|awk '{print $2}'|sort -r`

   for VAR_PID in $PIDS ; do
      kill $VAR_PID > /dev/null 2>&1
   done
   
   # 因为有dockerd父进程和docker-containerd子进程，因此预先设置COUNT=2
   COUNT=2
   echo -e "stoping...\c"
   while [ $COUNT -gt 0 ]; do
      echo -e ".\c"
      sleep 0.05
      COUNT=`ps -ef |grep $PID |grep -v grep |wc -l`
      if [ $COUNT -eq 0 ]; then
        echo -e "\ndockerd has been stoped"
        break
      fi
   done
   # restart的时候会存在无法启动dockerd进程的问题。(因为PID值还是原先停掉的dockerd进程id)
   PID=-1
}

restart() {
   stop
   start
}

case "$1" in
    'start')
        start
        ;;
    'stop')
        stop
        ;;
    'status')
        status
        ;;
    'restart')
        restart
        ;;
    *)
    echo "usage: $0 {start|stop|restart|status}"
    exit 1
    ;;
esac

总结

踩了好多坑，还是一点点解决了，有点抓狂，有点惊喜；还是得多多总结，多多把遇到的坑，怎么解决的经历整理成文，分享出来，以免更多人踩同样的坑。希望此文对有需要在CentOS6.6或CentOS6.x上安装docker的读者有一些帮助。

参考资料

• Get Docker CE for CentOS https://docs.docker.com/install/linux/docker-ce/centos/
• Install Docker CE from binaries https://docs.docker.com/install/linux/docker-ce/binaries/