docker可以说是去年最热的技术，也是业界大谈特谈的技术，到了今年有很多公司已经将docker应用于自己的生产环境。Docker已经从一个工具转化成平台，小生态圈。作为一名程序员应该与时俱进，学习新技术，不断地提高自己。
升级内核
docker要求linux内核版本3.12以上，作为常用linux2.26.32版本，虽然也可以安装docker，但是有一些特性不支持，所以第一步就是升级内核。个人选择最新的长期维护版本升级linux4.13,内核升级最关键的一件事情就是配置内核，关于内核支持docker的内核配置文件，如果不想自己动手配置内核，可以参考Linux-4.13-configfordocker;
在未正确配置linux内核会出现以下一些错误：
- docker启动过程中iptables命令执行失败，原因是 iptables模块没有配置
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[root@localhost ~]# docker -d
INFO[0000] Listening for HTTP on unix (/var/run/docker.sock)
INFO[0000] [graphdriver] using prior storage driver "devicemapper"
FATA[0000] Error starting daemon: Error initializing network controller: Error creating default "bridge" network: Failed to Setup IP tables: Unable to enable NAT rule: iptables failed: iptables -t nat -I POSTROUTING -s 172.17.42.1/16 ! -o docker0 -j MASQUERADE: iptables v1.4.7: can't initialize iptables table `nat': Table does not exist (do you need to insmod?)
Perhaps iptables or your kernel needs to be upgraded.
(exit status 3)
You have new mail in /var/spool/mail/root
[root@localhost ~]#
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- cgroup创建失败，具体参考stackoverflow
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[root@localhost ~]# service docker start
Starting cgconfig service: Error: cannot mount memory to /cgroup/memory: No such file or directory
/sbin/cgconfigparser; error loading /etc/cgconfig.conf: Cgroup mounting failed
Failed to parse /etc/cgconfig.conf or /etc/cgconfig.d[FAILED]
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具体内核升级过程参考如下：
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[root@localhost linux-4.1.13]# cp /share/github/docker-way/env/linux-4.1.3-configfordocker .config
[root@localhost linux-4.1.13]# sh -c 'yes "" | make oldconfig'
[root@localhost linux-4.1.13]# make -j2 bzImage
[root@localhost linux-4.1.13]# make -j2 modules
[root@localhost linux-4.1.13]# make -j2 modules_install
[root@localhost linux-4.1.13]# make install
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检查grub配置，修改并将linux-4.13作为默认启动项，重启系统，系统启动成功后，查看内核版本：
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[root@localhost ~]# uname -a
Linux localhost.localdomain 4.1.13 #1 SMP Sat Dec 5 11:17:50 CST 2015 x86_64 x86_64 x86_64 GNU/Linux
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安装device-mapper
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[root@localhost ~]#yum install -y device-mapper
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安装docker
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[root@localhost ~]# yum -y install docker-io
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安装完成后，检查docker是否能够正确启动
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[root@localhost ~]# docker -d
INFO[0000] [graphdriver] using prior storage driver "devicemapper"
INFO[0000] Listening for HTTP on unix (/var/run/docker.sock)
WARN[0000] Your kernel does not support swap memory limit.
INFO[0000] Loading containers: start.
INFO[0000] Loading containers: done.
INFO[0000] Daemon has completed initialization
INFO[0000] Docker daemon commit=786b29d execdriver=native-0.2 graphdriver=devicemapper version=1.7.1
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没有错误，接下来可以开启一段docker学习之旅了!
(更新)
Uninstall old versions
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sudo apt-get remove docker docker-engine docker.io containerd runc
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install
How To Install and Use Docker on Ubuntu 18.04