目前紅帽RHEL系統下面安裝docker可以有兩種方式：一種是使用curl獲得docker的安裝指令碼進行安裝，還有一種是使用yum包管理器來安裝docker。

一、使用安裝指令碼安裝。

備註：你可以按照同樣的步驟在CentOS系統下面安裝docker。

1. 使用一個有sudo許可權的帳號登入紅帽系統。

2. 更新現有的yum包。

   $ sudo yum update 

3. 執行docker安裝指令碼。

   $ curl -sSL https://get.docker.com/ | sh 

4. 啟動docker服務。

   $ sudo service docker start

5. 確認docker安裝成功。

   $ sudo docker run hello-world
   Unable to
    
    find image 'hello-world:latest' locally
   latest: Pulling from hello-world
   a8219747be10: Pull complete 91c95931e552: Already exists 
   hello-world:latest: The image you are pulling has been verified. Important: image verification is a tech preview feature and should not be relied on to provide security.
    
    Digest: sha256:aa03e5d0d5553b4c3473e89c8619cf79df368babd1.7.1cf5daeb82aab55838d
   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.
           (Assuming it was not already locally available.) 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
   For more examples and ideas, visit: http://docs.docker.com/userguide/

二、使用yum包安裝

1. 使用有sudo許可權的帳號登入系統。

2. 更新yum包。

   $ sudo yum update 

3. 新增docker源。

   $ cat >/etc/yum.repos.d/docker.repo <<-EOF
   [dockerrepo]
   name=Docker Repository
   baseurl=https://yum.dockerproject.org/repo/main/centos/7 enabled=1 gpgcheck=1 gpgkey=https://yum.dockerproject.org/gpg EOF

4. 使用yum命令安裝docker。

   $ sudo yum install docker-engine 

5. 啟動docker服務。

   $ sudo service docker start

6. 確認docker是否安裝成功。

   $ sudo docker run hello-world