本问是根据docker官方文档翻译，原文：https://docs.docker.com/engine/installation/linux/ubuntulinux/

Docker 支持以下 Ubuntu 系统:

• Ubuntu Xenial 16.04 (LTS)
• Ubuntu Wily 15.10
• Ubuntu Trusty 14.04 (LTS)
• Ubuntu Precise 12.04 (LTS)

本页内容指引你安装使用由Docker管理的正式包和管理包. 使用这些安装包能确保你安装 Docker最新发行包. 如果你想安装并使用Ubuntu管理提供的软件包,参照Ubuntu文档.

备注: Ubuntu Utopic 14.10 和 15.04 依旧在 Docker’sAPT仓库中，但不再提供官方技术支持.

前提条件

Docker要求是64位Ubuntu（无论哪个版本）。另外，内核必须在最小为3.10。3.10最新版本或更新的版本也行。

3.10之前版本缺少docker运行所需要的特征一些容器。这些老版本的bug，经常导致数据损失。

使用命令：uname -r来显示内核版本:

$ uname -r
3.11.0-15-generic

备注: 如果你之前安装过Docker 使用的APT,确保升级你的APT源 到 Docker新版.

更新APT源

Docker’sAPT仓库 包括 Docker 1.7.1 及更高版本. 为了设定APT使用最新仓库的软件包，:

1. 使用sudoorroot权限登陆计算机.

2. 打开 terminal window（命令窗口）.

3. 更新安装包信息,确保 APT 使用https协议,同时CA 证书已经被安装.

   $ sudo apt-get update $ sudo apt-get install apt-transport-https ca-certificates

4. 添加新的GPGkey.

   $ sudo apt-key adv --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys 58118E89F3A912897C070ADBF76221572C52609D

5. 用编辑器打开 /etc/apt/sources.list.d/docker.list.

   如果不存在，则新建一个

6. 删除任何现有输入.

7. 添加与您Ubuntu操作系统相关条目。

   该条目可以是：

   • On Ubuntu Precise 12.04 (LTS)

     deb https://apt.dockerproject.org/repo ubuntu-precise main

   • On Ubuntu Trusty 14.04 (LTS)

     deb https://apt.dockerproject.org/repo ubuntu-trusty main

   • Ubuntu Wily 15.10

     deb https://apt.dockerproject.org/repo ubuntu-wily main 

   • Ubuntu Xenial 16.04 (LTS)

     deb https://apt.dockerproject.org/repo ubuntu-xenial main

   注意：通过命令lsb_release-c查看上面对应的版本，不要都添加上
   Codename: trusty
   
   查看Ubuntu的版本号

   在终端中执行下列指令：
   
   cat /etc/issue
   
   可以查看当前正在运行的 Ubuntu 的版本号。其输出结果类似下面的内容：
   
   Ubuntu 12.04.1 LTS \n \l
   
   方法二
   
   使用 lsb_release 命令也可以查看 Ubuntu 的版本号，与方法一相比，内容更为详细。执行指令如下：
   
   lsb_release -a
   
   将输出结果：

   No LSB modules are available.

   Distributor ID: Ubuntu
   Description: Ubuntu 12.04.1 LTS
   Release: 12.04
   Codename: precise

   备注: Docker没有为所有架构提供代码包 .你可以找到 nightly built binaries inhttps://master.dockerproject.org. To install docker on a multi-architecture system,add an[arch=...]clause to the entry. 详细内容参考Debian Multiarch wiki.

8. 保存并关闭 /etc/apt/sources.list.d/docker.listfile.

9. 或这样添加docker源

   $ echo "deb https://apt.dockerproject.org/repo ubuntu-trusty main" | sudo tee /etc/apt/sources.list.d/docker.list

10. 更新APT软件包索引.

    $ sudo apt-get update

11. 清除旧的repo if it exists.

    $ sudo apt-get purge lxc-docker

12. 确保APT是从正确的代码库拉取下来的.

    $ apt-cache policy docker-engine

    至此，你可以 使用命令apt-get upgrade,APT从新代码库拉取代码.

Ubuntu 版本相关的先决条件

• Ubuntu Xenial 16.04 (LTS)
• Ubuntu Wily 15.10
• Ubuntu Trusty 14.04 (LTS)

针对Ubuntu Trusty,Wily,and Xenial,推荐安装 thelinux-image-extra-*内核包. linux-image-extra-*包允许你使用aufs存储驱动.

为了安装linux-image-extra-*:

1. 打开主机命令窗口.

2. 更新包管理器.

   $ sudo apt-get update

3. 安装推荐包.

   $ sudo apt-get install linux-image-extra-$(uname -r) linux-image-extra-virtual

4. 继续安装 Docker.

Ubuntu Precise 12.04 (LTS)

针对Ubuntu Precise,Docker 要求是 3.13内核. 如果内核版本早于 3.13,必须更新. 参考如下表格来对比不同包对运行环境的要求:

为了更新linux内核并且安装附加包,通过以下步骤:

1. 打开主机命令窗口.

2. 更新包管理器.

   $ sudo apt-get update

3. 安装必需包和可选包

   $ sudo apt-get install linux-image-generic-lts-trusty

   根据你的运行环境,你可能需要根据之前提供表格所描述内容安装其他内容.

4. 重启主机.

   $ sudo reboot

5. 重启之后,继续安装Docker.

安装

确保你已经安装过你的Ubuntu版本所需前提要求.

然后,通过以下步骤安装Docker:

1. 用具有sudo权限的用户登陆Ubuntu.

2. Update yourAPTpackage index.

   $ sudo apt-get update

3. 安装 Docker.

   $ sudo apt-get install docker-engine

4. 开始使用docker.

   $ sudo service docker start

5. 确认docker已被正确安装.

   $ sudo docker run hello-world

   这个命令下载一个测试图片并且在容器（container）中运行. 然后容器container运行,打印出相关信息.说明安装成功.

可选配置

下面驱动包含一些可选步骤用来配置Ubuntu环境下Docker.

• Create a docker group
• Adjust memory and swap accounting
• Enable UFW forwarding
• Configure a DNS server for use by Docker
• Configure Docker to start on boot

创建 Docker group

docker进程（daemon）绑定在 Unix套接字（socket）， 而不是TCP端口（port）. 由于Unix默认是 socket权限归root用户所有，其他用户可以通过sudo访问. 由此,docker进程通常使用root用户运行.

为了避免每次使用docker命令都不得不使用sudo,创建名为docker的Unix group并add users to it. 当dockerdaemon 开始,dockergroup就会拥有Unix socket 的读写权限（read/writable）.

警告: Thedockergroup is equivalent to theroot用户; For details on how this impacts security in your system,查看Docker Daemon Attack Surface查看细节.

为了dockergroup and添加用户user:

1. 使用具有sudo权限得用户登录Ubuntu.

2. 创建dockergroup.

   $ sudo groupadd docker

3. 添加user到dockergroup.

   $ sudo usermod -aG docker $USER

4. Log out and log back in.

   This ensures your user is running with the correct permissions.

5. 确认不使用sudo可以运行docker.

   $ docker run hello-world

   如果提示失败信息与下面相似:

   Cannot connect to the Docker daemon. Is 'docker daemon' running on this host?

   检查DOCKER_HOST环境变量 没有设置shell. 如果这样,重置他.

Adjust memory and swap accounting

When users run Docker,they may see these messages when working with an image:

WARNING: Your kernel does not support cgroup swap limit. WARNING: Your
kernel does not support swap limit capabilities. Limitation discarded.

To prevent these messages,enable memory and swap accounting on your system. Enabling memory and swap accounting does induce both a memory overhead and a performance degradation even when Docker is not in use. The memory overhead is about 1% of the total available memory. The performance degradation is roughly 10%.

To enable memory and swap on system using GNU GRUB (GNU GRand Unified Bootloader),do the following:

1. Log into Ubuntu as a user withsudoprivileges.

2. Edit the/etc/default/grubfile.

3. Set theGRUB_CMDLINE_LINUXvalue as follows:

   GRUB_CMDLINE_LINUX="cgroup_enable=memory swapaccount=1"

4. Save and close the file.

5. Update GRUB.

   $ sudo update-grub

6. Reboot your system.

Enable UFW forwarding

If you useUFW (Uncomplicated Firewall)on the same host as you run Docker,you’ll need to do additional configuration. Docker uses a bridge to manage container networking. By default,UFW drops all forwarding traffic. As a result,for Docker to run when UFW is enabled,you must set UFW’s forwarding policy appropriately.

Also,UFW’s default set of rules denies all incoming traffic. If you want to reach your containers from another host allow incoming connections on the Docker port. The Docker port defaults to2376if TLS is enabled or2375when it is not. If TLS is not enabled,communication is unencrypted. By default,Docker runs without TLS enabled.

To configure UFW and allow incoming connections on the Docker port:

1. Log into Ubuntu as a user withsudoprivileges.

2. Verify that UFW is installed and enabled.

   $ sudo ufw status

3. Open the/etc/default/ufwfile for editing.

   $ sudo nano /etc/default/ufw

4. Set theDEFAULT_FORWARD_POLICYpolicy to:

   DEFAULT_FORWARD_POLICY="ACCEPT"

5. Save and close the file.

6. Reload UFW to use the new setting.

   $ sudo ufw reload

7. Allow incoming connections on the Docker port.

   $ sudo ufw allow 2375/tcp

Configure a DNS server for use by Docker

Systems that run Ubuntu or an Ubuntu derivative on the desktop typically use127.0.0.1as the defaultnameserverin/etc/resolv.conffile. The NetworkManager also sets updnsmasqto use the real DNS servers of the connection and sets upnameserver 127.0.0.1in /etc/resolv.conf.

When starting containers on desktop machines with these configurations,Docker users see this warning:

WARNING: Local (127.0.0.1) DNS resolver found in resolv.conf and containers
can't use it. Using default external servers : [8.8.8.8 8.8.4.4]

The warning occurs because Docker containers can’t use the local DNS nameserver. Instead,Docker defaults to using an external nameserver.

To avoid this warning,you can specify a DNS server for use by Docker containers. Or,you can disablednsmasqin NetworkManager. Though,disablingdnsmasqmight make DNS resolution slower on some networks.

The instructions below describe how to configure the Docker daemon running on Ubuntu 14.10 or below. Ubuntu 15.04 and above usesystemdas the boot and service manager. Refer tocontrol and configure Docker with systemdto configure a daemon controlled bysystemd.

To specify a DNS server for use by Docker:

1. Log into Ubuntu as a user withsudoprivileges.

2. Open the/etc/default/dockerfile for editing.

   $ sudo nano /etc/default/docker

3. Add a setting for Docker.

   DOCKER_OPTS="--dns 8.8.8.8"

   Replace8.8.8.8with a local DNS server such as192.168.1.1. You can also specify multiple DNS servers. Separated them with spaces,for example:

   --dns 8.8.8.8 --dns 192.168.1.1

   Warning: If you’re doing this on a laptop which connects to varIoUs networks,make sure to choose a public DNS server.

4. Save and close the file.

5. Restart the Docker daemon.

   $ sudo service docker restart

Or,as an alternative to the prevIoUs procedure,disablednsmasqin NetworkManager (this might slow your network).

1. Open the/etc/NetworkManager/NetworkManager.conffile for editing.

   $ sudo nano /etc/NetworkManager/NetworkManager.conf

2. Comment out thedns=dnsmasqline:

   dns=dnsmasq

3. 保存并关闭.

4. 重启NetworkManager 和 Docker.

   $ sudo restart network-manager $ sudo restart docker

Configure Docker to start on boot

Ubuntu usessystemdas its boot and service manager15.04onwards andupstartfor versions14.10and below.

For15.04and up,to configure thedockerdaemon to start on boot,run

$ sudo systemctl enable docker

For14.10and below the above installation method automatically configuresupstartto start the docker daemon on boot

更新Docker

使用apt-get来安装Docker最新版:

$ sudo apt-get upgrade docker-engine

卸载

卸载Docker包:

$ sudo apt-get purge docker-engine

卸载Docker包及依赖:

$ sudo apt-get autoremove --purge docker-engine

上面命令会删除images,containers,volumes,user created configuration files on your host. If you wish to delete all images,and volumes run the following command:

$ rm -rf /var/lib/docker

You must delete the user created configuration files manually.

参考：

http://www.cnblogs.com/zzcit/p/5845717.html

http://lizhenliang.blog.51cto.com/7876557/1728931

sudo service docker start 出现以下错误解决办法

start: Unable to connect to Upstart: Failed to connect to socket /com/ubuntu/upstart: Connection refused

Note: There were multiple problems reported when applying the change on some installations. I particularly discourage to do this on a non-virtual machine! If you still want to give this fix a try,make sure you have asnapshot/backup!

This is another remind me blog entry: If you suffer from above message,then you are probably using Ubuntu in a virtual machine. If so,you will need to modify initctl to simply return true using the following steps. First,you need to tell dpkg,that you are going to change the upstart package installationusing:

sudo dpkg-divert --local --rename --add /sbin/initctl

Then,you need to create a dummy initctl as a link totrue:

ln -s /bin/true /sbin/initctl

参考：

https://www.nesono.com/node/368

重点参考：

Ubuntu16.04安装Docker1.12+开发实例+hello world+web应用容器 http://blog.csdn.net/dream_an/article/details/51985170 https://docs.docker.com/engine/installation/linux/ubuntu/