> 文章参考：https://yeasy.gitbook.io/docker_practice/install/centos
## 卸载旧版本
旧版本的 Docker 称为 `docker` 或者 `docker-engine`，使用以下命令卸载旧版本：
```shell
$ sudo yum remove docker \
docker-client \
docker-client-latest \
docker-common \
docker-latest \
docker-latest-logrotate \
docker-logrotate \
docker-selinux \
docker-engine-selinux \
docker-engine
```
## 使用 yum 安装
执行以下命令安装依赖包：
```shell
$ sudo yum install -y yum-utils
```
鉴于国内网络问题，强烈建议使用国内源，官方源请在注释中查看。
执行下面的命令添加 `yum` 软件源：
```shell
$ sudo yum-config-manager \
--add-repo \
https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
$ sudo sed -i 's/download.docker.com/mirrors.aliyun.com\/docker-ce/g' /etc/yum.repos.d/docker-ce.repo
# 官方源
# $ sudo yum-config-manager \
# --add-repo \
# https://download.docker.com/linux/centos/docker-ce.repo
```
如果需要测试版本的 Docker 请执行以下命令：
```shell
$ sudo yum-config-manager --enable docker-ce-test
```
## 安装 Docker
更新 `yum` 软件源缓存，并安装 `docker-ce`。
```shell
$ sudo yum install docker-ce docker-ce-cli containerd.io
```
## 启动 Docker
```shell
$ sudo systemctl enable docker
$ sudo systemctl start docker
```
## 测试 Docker 是否安装正确
```shell
$ docker run --rm hello-world
Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
b8dfde127a29: Pull complete
Digest: sha256:308866a43596e83578c7dfa15e27a73011bdd402185a84c5cd7f32a88b501a24
Status: Downloaded newer image for hello-world:latest
Hello from Docker!
This message shows that your installation appears to be working correctly.
To generate this message, Docker took the following steps:
1. The Docker client contacted the Docker daemon.
2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
(amd64)
3. The Docker daemon created a new container from that image which runs the
executable that produces the output you are currently reading.
4. The Docker daemon streamed that output to the Docker client, which sent it
to your terminal.
To try something more ambitious, you can run an Ubuntu container with:
$ docker run -it ubuntu bash
Share images, automate workflows, and more with a free Docker ID:
https://hub.docker.com/
For more examples and ideas, visit:
https://docs.docker.com/get-started/
```
若能正常输出以上信息，则说明安装成功。
## 小记
### 镜像加速
如果在使用过程中发现拉取 Docker 镜像十分缓慢，可以配置 Docker [国内镜像加速]()。
下面介绍阿里云的镜像加速
1、登录阿里云服务器
2、找到容器加速服务
3、选择对应centos的操作文档进行配置即可。
附配置（以下是阿里云官方文档）：
针对Docker客户端版本大于 1.10.0 的用户
您可以通过修改daemon配置文件/etc/docker/daemon.json来使用加速器阿里云
```shell
$ sudo mkdir -p /etc/docker
$ sudo tee /etc/docker/daemon.json <<-'EOF'
{
"registry-mirrors": ["https://ksi66l4y.mirror.aliyuncs.com"]
}
EOF
$ sudo systemctl daemon-reload
$ sudo systemctl restart docker
```
Docker教程
