Install Docker Engine on CentOS 在CentOS 7 上安装Docker

Install Docker Engine on CentOS

OS Requirements 系统要求

To install Docker Engine,you need a maintained version of CentOS 7. Archives versions arent supported or testes.

要安装Docker引擎，需要CentOS 7的维护版本。不支持或测试存档版本。

The centos-extras repository must be enabled. This repository is enabled by default.but if you hava disabled it ,you need to re-enabled it

必须启用centos-extras存储库。默认情况下该存储库是启用的，但是如果您已经禁用了它，则需要重新启用它。

The overlay2 storage driver is recommended.

建议使用overlay2存储驱动程序。

Uninstall old versions 卸载旧版本

Older versions of Docker were called docker or docker-engine. If these are installed, uninstall them, along with associated dependencies.

Docker的旧版本被称为Docker或Docker -engine。如果安装了这些，请卸载它们以及相关的依赖项。

$ sudo yum remove docker \

                  docker-client \

                  docker-client-latest \

                  docker-common \

                  docker-latest \

                  docker-latest-logrotate \

                  docker-logrotate \

                  docker-engine

It’s OK if yum reports that none of these packages are installed.

如果yum报告没有安装这些包，就说明可以了

The contents of /var/lib/docker/, including images, containers, volumes, and networks, are preserved. The Docker Engine package is now called docker-ce.

保存/var/lib/docker/的内容，包括图像、容器、卷和网络。Docker Engine包现在称为Docker -ce。

Installation methods

You can install Docker Engine in different ways, depending on your needs:

你可以根据需要，使用不同的方式安装

Most users set up Docker’s repositories and install from them, for ease of installation and upgrade tasks. This is the recommended approach.
大多数用户设置了Docker的存储库并从它们进行安装，以方便安装和升级任务。这是推荐的方法。在线安装
Some users download the RPM package and install it manually and manage upgrades completely manually. This is useful in situations such as installing Docker on air-gapped systems with no access to the internet.
一些用户下载RPM包并手动安装，并完全手动管理升级。这在一些情况下非常有用，比如在没有访问internet的被隔离的系统上安装Docker。离线安装
In testing and development environments, some users choose to use automated convenience scripts to install Docker.
在测试和开发环境中，一些用户选择使用自动化的方便脚本来安装Docker。

Install using the repository 使用存储库安装

Before you install Docker Engine for the first time on a new host machine, you need to set up the Docker repository. Afterward, you can install and update Docker from the repository.

首次安装Dcoker Engine之前，需要设置Docker repository，然后从rspository安装和更新Docker

SET UP THE REPOSITORY 设置存储库

Install the yum-utils package (which provides the yum-config-manager utility) and set up the stable repository.

安装yum-utils包（它提供了yum-config-manager 程序）并设置稳定的存储库，国内用户需要使用阿里存储库

$ sudo yum install -y yum-utils

$ sudo yum-config-manager \

    --add-repo \

    https://download.docker.com/linux/centos/docker-ce.repo

阿里源

$ sudo yum-config-manager \

    --add-repo \

    http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo

Optional: Enable the nightly or test repositories. 可选：开启每日存储库或者测试库

These repositories are included in the docker.repo file above but are disabled by default. You can enable them alongside the stable repository. The following command enables the nightly repository.

这些存储库包含在docker中的repo文件，但默认情况下是禁用的。您可以在稳定存储库的同时启用它们。下面的命令启用了每日存储库。
```
$ sudo yum-config-manager --enable docker-ce-nightly
```
To enable the test channel, run the following command:

要启用测试通道，请运行以下命令:
```
$ sudo yum-config-manager --enable docker-ce-test
```
You can disable the nightly or test repository by running the yum-config-manager command with the --disable flag. To re-enable it, use the --enable flag. The following command disables the nightly repository.

您可以通过运行带有 -disable标志的yum-config-manager命令来禁用每日存储库或测试存储库。要重新启用它，使用·--enable标志。下面的命令禁用夜间存储库。
```
$ sudo yum-config-manager --disable docker-ce-nightly
```
INSTALL DOCKER ENGINE 安装Docker Engine
1. Install the latest version of Docker Engine and containerd, or go to the next step to install a specific version:
安装Docker Engine和containerd的最新版本，或者进入下一步安装特定版本:
```
$ sudo yum install docker-ce docker-ce-cli containerd.io
```
If prompted to accept the GPG key, verify that the fingerprint matches 060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35, and if so, accept it.

如果提示接受GPG密钥，请验证指纹是否与060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35匹配，如果匹配，请接受。
1. To install a specific version of Docker Engine, list the available versions in the repo, then select and install:
要安装特定版本的Docker引擎，请在repo中列出可用的版本，然后选择并安装:

a. List and sort the versions available in your repo. This example sorts results by version number, highest to lowest, and is truncated:

a.列出并排序可用的版本。这个示例按照版本号对结果进行排序。从最高到最低并截断
```
$ yum list docker-ce --showduplicates | sort -r

docker-ce.x86_64  3:18.09.1-3.el7                     docker-ce-stable

docker-ce.x86_64  3:18.09.0-3.el7                     docker-ce-stable

docker-ce.x86_64  18.06.1.ce-3.el7                    docker-ce-stable

docker-ce.x86_64  18.06.0.ce-3.el7                    docker-ce-stable
```
The list returned depends on which repositories are enabled, and is specific to your version of CentOS (indicated by the .el7 suffix in this example).

返回的列表取决于启用了哪些存储库，并且特定于您的CentOs版本

b. Install a specific version by its fully qualified package name, which is the package name (docker-ce) plus the version string (2nd column) starting at the first colon (:), up to the first hyphen, separated by a hyphen (-). For example,

b.通过完全限定的包名安装一个特定版本，包名是包名(docker-ce)加上版本字符串(第二列)，从第一个冒号(:)开始，直到第一个连字符，用连字符(-)分隔。例如,docker-ce-18.09.1
```
$ sudo yum install docker-ce-<VERSION_STRING> docker-ce-cli-<VERSION_STRING> containerd.io

eg: yum install docker-ce-18.09.9 docker-ce-cli-18.09.9 containerd.io
```
Docker is installed but not started. The docker group is created, but no users are added to the group.

Docker已安装，但尚未启动。docker组被创建，但是没有用户被添加到组中

Start Docker.
```
$ sudo systemctl start docker
```

添加国内的镜像源，否则后续无法验证

sudo mkdir -p /etc/docker

sudo tee /etc/docker/daemon.json <<-'EOF'

{

  "registry-mirrors": ["https://xaw9lc34.mirror.aliyuncs.com"]

}

EOF

sudo systemctl daemon-reload

sudo systemctl restart docker

Verify that Docker Engine is installed correctly by running the hello-world image.
```
$ 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 and exits.

这个命令下载一个测试映像并在容器中运行它。当容器运行时，它打印一条信息性消息并退出。

Docker Engine is installed and running. You need to use sudo to run Docker commands. Continue to Linux postinstall to allow non-privileged users to run Docker commands and for other optional configuration steps.