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’s APT 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’s APT 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 sudo or root 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
     

   备注: Docker没有为所有架构提供代码包 .你可以找到 nightly built binaries in https://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.list file.
9. 更新APT 软件包索引.

   $ sudo apt-get update
   

10. 清除旧的repo if it exists.

    $ sudo apt-get purge lxc-docker
    

11. 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 the linux-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 your APT package 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）. By default that Unix socket is owned by the user root and other users can access it withsudo. For this reason, docker daemon always runs as the root user.

To avoid having to use sudo when you use the docker command, create a Unix group called docker and add users to it. When the docker daemon starts, it makes the ownership of the Unix socket read/writable by the docker group.

Warning: The docker group is equivalent to the root user; For details on how this impacts security in your system, see Docker Daemon Attack Surface for details.

To create the docker group and add your user:

1. Log into Ubuntu as a user with sudo privileges.
2. Create the docker group.

   $ sudo groupadd docker
   

3. Add your user to docker group.

   $ sudo usermod -aG docker $USER
   

4. Log out and log back in.

   This ensures your user is running with the correct permissions.

5. Verify your work by running docker without sudo.

   $ docker run hello-world
   

   If this fails with a message similar to this:

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

   Check that the DOCKER_HOST environment variable is not set for your shell. If it is, unset it.

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 with sudo privileges.
2. Edit the /etc/default/grub file.
3. Set the GRUB_CMDLINE_LINUX value 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 use UFW (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 to 2376 if TLS is enabled or 2375 when 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 with sudo privileges.
2. Verify that UFW is installed and enabled.

   $ sudo ufw status
   

3. Open the /etc/default/ufw file for editing.

   $ sudo nano /etc/default/ufw
   

4. Set the DEFAULT_FORWARD_POLICY policy 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 use127.0.0.1 as the default nameserver in /etc/resolv.conf file. The NetworkManager also sets up dnsmasq to use the real DNS servers of the connection and sets up nameserver 127.0.0.1 in /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 disable dnsmasq in NetworkManager. Though, disablingdnsmasq might 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 use systemd as the boot and service manager. Refer to control and configure Docker with systemd to configure a daemon controlled by systemd.

To specify a DNS server for use by Docker:

1. Log into Ubuntu as a user with sudo privileges.
2. Open the /etc/default/docker file for editing.

   $ sudo nano /etc/default/docker
   

3. Add a setting for Docker.

   DOCKER_OPTS="--dns 8.8.8.8"
   

   Replace 8.8.8.8 with a local DNS server such as 192.168.1.1. 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, disable dnsmasq in NetworkManager (this might slow your network).

1. Open the /etc/NetworkManager/NetworkManager.conf file for editing.

   $ sudo nano /etc/NetworkManager/NetworkManager.conf
   

2. Comment out the dns=dnsmasq line:

   dns=dnsmasq
   

3. Save and close the file.
4. Restart both the NetworkManager and Docker.

   $ sudo restart network-manager
   $ sudo restart docker
   

Configure Docker to start on boot

Ubuntu uses systemd as its boot and service manager 15.04 onwards andupstart for versions 14.10 and below.

For 15.04 and up, to configure the docker daemon to start on boot, run

$ sudo systemctl enable docker

For 14.10 and below the above installation method automatically configuresupstart to start the docker daemon on boot

Upgrade Docker

To install the latest version of Docker with apt-get:

$ sudo apt-get upgrade docker-engine

卸载

To uninstall the Docker package:

$ sudo apt-get purge docker-engine

To uninstall the Docker package and dependencies that are no longer needed:

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

The above commands will not remove images, containers, volumes, or user created configuration files on your host. If you wish to delete all images, containers, and volumes run the following command:

$ rm -rf /var/lib/docker

You must delete the user created configuration files manually.