ubuntu下安装docker

官方原文：https://docs.docker.com/engine/installation/linux/ubuntulinux/

Ubuntu

Docker is supported on these Ubuntu operating systems:
Ubuntu Xenial 16.04 (LTS)
Ubuntu Wily 15.10
Ubuntu Trusty 14.04 (LTS)
Ubuntu Precise 12.04 (LTS)

This page instructs you to install using Docker-managed release packages and installation mechanisms. Using these packages ensures you get the latest release of Docker. If you wish to install using Ubuntu-managed packages, consult your Ubuntu documentation.

Note: Ubuntu Utopic 14.10 and 15.04 exist in Docker’s 

APT

repository
but are no longer officially supported.

Prerequisites

Docker requires a 64-bit installation regardless of your Ubuntu version. Additionally, your
kernel must be 3.10 at minimum. The latest 3.10 minor version or a newer maintained version are also acceptable.

Kernels older than 3.10 lack some of the features required to run Docker containers. These older versions are known to have bugs which cause data loss and frequently panic under certain conditions.

To check your current kernel version, open a terminal and use

uname
-r

 to display your kernel version:

$ uname -r
3.11.0-15-generic

Note: If you previously installed Docker using 

APT

,
make sure you update your 

APT

 sources
to the new Docker repository.

Update your apt sources

Docker’s 

APT

 repository contains
Docker 1.7.1 and higher. To set

APT

 to
use packages from the new repository:

Log into your machine as a user with 

sudo

 or 

root

 privileges.

Open a terminal window.

Update package information, ensure that APT works with the

https

 method,
and that CA certificates are installed.

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

Add the new 

GPG

 key.

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

Open the 

/etc/apt/sources.list.d/docker.list

 file
in your favorite editor.

If the file doesn’t exist, create it.

Remove any existing entries.

Add an entry for your Ubuntu operating system.

The possible entries are:

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

Note: Docker does not provide packages for all architectures. You can find nightly built binaries inhttps://master.dockerproject.org.
To install docker on a multi-architecture system, add an 

[arch=...]

 clause
to the entry. Refer to the Debian Multiarch wiki for details.

Save and close the 

/etc/apt/sources.list.d/docker.list

file.

Update the 

APT

 package index.

$ sudo apt-get update

Purge the old repo if it exists.

$ sudo apt-get purge lxc-docker

Verify that 

APT

 is pulling from
the right repository.

$ apt-cache policy docker-engine

From now on when you run 

apt-get
upgrade

, 

APT

 pulls from the new repository.

Prerequisites by Ubuntu Version

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

For Ubuntu Trusty, Wily, and Xenial, it’s recommended to install the

linux-image-extra

 kernel
package. The 

linux-image-extra

package
allows you use the 

aufs

 storage driver.

To install the 

linux-image-extra

 package
for your kernel version:

Open a terminal on your Ubuntu host.

Update your package manager.

$ sudo apt-get update

Install the recommended package.

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

Go ahead and install Docker.

If you are installing on Ubuntu 14.04 or 12.04, 

apparmor

 is
required. You can install it using: 

apt-get
install apparmor

Ubuntu Precise 12.04 (LTS)

For Ubuntu Precise, Docker requires the 3.13 kernel version. If your kernel version is older than 3.13, you must upgrade it. Refer to this table to see which packages are required for your environment:

linux-image-generic-lts-trusty	Generic Linux kernel image. This kernel has AUFS built in. This is required to run Docker.
linux-headers-generic-lts-trusty	Allows packages such as ZFS and VirtualBox guest additions which depend on them. If you didn’t install the headers for your existing kernel, then you can skip these headers for the”trusty” kernel. If you’re unsure, you should include this package for safety.
xserver-xorg-lts-trusty	Optional in non-graphical environments without Unity/Xorg.Required when running Docker on machine with a graphical environment.  To learn more about the reasons for these packages, read the installation instructions for backported kernels, specifically the LTS Enablement Stack— refer to note 5 under each version.
libgl1-mesa-glx-lts-trusty

 

To upgrade your kernel and install the additional packages, do the following:

Open a terminal on your Ubuntu host.

Update your package manager.

$ sudo apt-get update

Install both the required and optional packages.

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

Depending on your environment, you may install more as described in the preceding table.

Reboot your host.

$ sudo reboot

After your system reboots, go ahead and install Docker.

Install

Make sure you have installed the prerequisites for your Ubuntu version.

Then, install Docker using the following:

Log into your Ubuntu installation as a user with 

sudo

 privileges.

Update your 

APT

 package index.

$ sudo apt-get update

Install Docker.

$ sudo apt-get install docker-engine

Start the 

docker

 daemon.

$ sudo service docker start

Verify 

docker

 is installed correctly.

$ sudo docker run hello-world

This command downloads a test image and runs it in a container. When the container runs, it prints an informational message. Then, it exits.

Optional configurations

This section contains optional procedures for configuring your Ubuntu to work better with 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

Create a Docker group

The 

docker

 daemon binds to a Unix
socket instead of a TCP port. By default that Unix socket is owned by the user 

root

 and
other users can access it with 

sudo

.
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, seeDocker
Daemon Attack Surface for details.

To create the 

docker

 group and
add your user:

Log into Ubuntu as a user with 

sudo

 privileges.

This procedure assumes you log in as the 

ubuntu

 user.

Create the 

docker

 group.

$ sudo groupadd docker

Add your user to 

docker

 group.

$ sudo usermod -aG docker ubuntu

Log out and log back in.

This ensures your user is running with the correct permissions.

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:

Log into Ubuntu as a user with 

sudo

 privileges.

Edit the 

/etc/default/grub

 file.

Set the 

GRUB_CMDLINE_LINUX

 value
as follows:

GRUB_CMDLINE_LINUX="cgroup_enable=memory swapaccount=1"

Save and close the file.

Update GRUB.

$ sudo update-grub

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:

Log into Ubuntu as a user with 

sudo

 privileges.

Verify that UFW is installed and enabled.

$ sudo ufw status

Open the 

/etc/default/ufw

 file
for editing.

$ sudo nano /etc/default/ufw

Set the 

DEFAULT_FORWARD_POLICY

 policy
to:

DEFAULT_FORWARD_POLICY="ACCEPT"

Save and close the file.

Reload UFW to use the new setting.

$ sudo ufw reload

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 use 

127.0.0.1

 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, disabling 

dnsmasq

 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:

Log into Ubuntu as a user with 

sudo

 privileges.

Open the 

/etc/default/docker

 file
for editing.

$ sudo nano /etc/default/docker

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.

Save and close the file.

Restart the Docker daemon.

$ sudo restart docker

   

Or, as an alternative to the previous procedure, disable

dnsmasq

 in
NetworkManager (this might slow your network).

Open the 

/etc/NetworkManager/NetworkManager.conf

 file
for editing.

$ sudo nano /etc/NetworkManager/NetworkManager.conf

Comment out the 

dns=dnsmasq

 line:

dns=dnsmasq

Save and close the file.

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
and 

upstart

 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 configures 

upstart

 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

Uninstallation

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.