摘要：出于安全考慮，一般系統(tǒng)上不會(huì)直接使用用戶。因此，更好地做法是將需要使用的用戶加入用戶組。建立組將當(dāng)前用戶加入組退出當(dāng)前終端并重新登錄，進(jìn)行如下測(cè)試。無需使用管理員權(quán)限測(cè)試運(yùn)行運(yùn)行列出鏡像倉庫名標(biāo)簽鏡像創(chuàng)建時(shí)間占用空間

1.1 查看當(dāng)前l(fā)inux內(nèi)核版本

uname -r #linux內(nèi)核要求3.10及以上

1.2 更行yum源

sudo yum update 

1.3 如果安裝過舊版本的話，卸載舊版本

sudo yum remove docker  docker-common docker-selinux docker-engine

1.4 安裝需要的軟件包，?yum-util 提供yum-config-manager功能，另外兩個(gè)是devicemapper驅(qū)動(dòng)依賴的

sudo yum install -y yum-utils device-mapper-persistent-data lvm2 

1.5 由于國(guó)內(nèi)網(wǎng)絡(luò)問題,建議使用國(guó)內(nèi)源,添加yum軟件源

sudo yum-config-manager --add-repo http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo  #阿里云鏡像源

已加載插件：fastestmirror, langpacks
adding repo from: http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo
grabbing file http://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo to /etc/yum.repos.d/docker-ce.repo
repo saved to /etc/yum.repos.d/docker-ce.repo

1.6 可以查看所有倉庫中所有docker版本，并選擇特定版本安裝

$ yum list docker-ce --showduplicates | sort -r

docker-ce.x86_64            18.06.0.ce-3.el7                    docker-ce-stable
docker-ce.x86_64            18.03.1.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            18.03.0.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            17.12.1.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            17.12.0.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            17.09.1.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            17.09.0.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            17.06.2.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            17.06.1.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            17.06.0.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            17.03.2.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            17.03.1.ce-1.el7.centos             docker-ce-stable
docker-ce.x86_64            17.03.0.ce-1.el7.centos             docker-ce-stable

1.7 安裝docker

$ sudo yum install docker-ce  #由于repo中默認(rèn)只開啟stable倉庫，故這里安裝的是最新穩(wěn)定版17.12.0
$ sudo yum install   # 例如:sudo yum install docker-ce-17.12.1.ce

已安裝:
  docker-ce.x86_64 0:17.12.1.ce-1.el7.centos                                                                                                            
作為依賴被安裝:
  audit-libs-python.x86_64 0:2.8.1-3.el7           checkpolicy.x86_64 0:2.5-6.el7                 container-selinux.noarch 2:2.66-1.el7               
  libsemanage-python.x86_64 0:2.5-11.el7           libtool-ltdl.x86_64 0:2.4.2-22.el7_3           policycoreutils-python.x86_64 0:2.5-22.el7          
  python-IPy.noarch 0:0.75-6.el7                   setools-libs.x86_64 0:3.3.8-2.el7             

完畢！

1.8 將docker加入開機(jī)啟動(dòng)

$ sudo systemctl start docker
$ sudo systemctl enable docker

1.9 驗(yàn)證安裝是否成功(有client和service兩部分表示docker安裝啟動(dòng)都成功了)

$ sudo docker version

Client:
 Version:    17.12.1-ce
 API version:    1.35
 Go version:    go1.9.4
 Git commit:    7390fc6
 Built:    Tue Feb 27 22:15:20 2018
 OS/Arch:    linux/amd64

Server:
 Engine:
  Version:    17.12.1-ce
  API version:    1.35 (minimum version 1.12)
  Go version:    go1.9.4
  Git commit:    7390fc6
  Built:    Tue Feb 27 22:17:54 2018
  OS/Arch:    linux/amd64
  Experimental:    false
  

默認(rèn)情況下，docker 命令會(huì)使用 Unix socket 與 Docker 引擎通訊。而只有 root 用戶和 docker 組的用戶才可以訪問 Docker 引擎的 Unix socket。出于安全考慮，一般 Linux 系統(tǒng)上不會(huì)直接使用 root 用戶。因此，更好地做法是將需要使用 docker 的用戶加入 docker 用戶組。

2.1 建立docker組

$ sudo groupadd docker

2.2 將當(dāng)前用戶加入 docker 組：

$ sudo usermod -aG docker $USER

2.3 退出當(dāng)前終端并重新登錄，進(jìn)行如下測(cè)試。

$ docker version #無需sudo使用管理員權(quán)限

 Client:
 Version:    17.12.1-ce
 API version:    1.35
 Go version:    go1.9.4
 Git commit:    7390fc6
 Built:    Tue Feb 27 22:15:20 2018
 OS/Arch:    linux/amd64

Server:
 Engine:
  Version:    17.12.1-ce
  API version:    1.35 (minimum version 1.12)
  Go version:    go1.9.4
  Git commit:    7390fc6
  Built:    Tue Feb 27 22:17:54 2018
  OS/Arch:    linux/amd64
  Experimental:    false

$ docker run hello-world #運(yùn)行hello world

Unable to find image "hello-world:latest" locally
latest: Pulling from library/hello-world
9db2ca6ccae0: Pull complete 
Digest: sha256:4b8ff392a12ed9ea17784bd3c9a8b1fa3299cac44aca35a85c90c5e3c7afacdc
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/engine/userguide/

$ docker image ls #列出鏡像

倉庫名              標(biāo)簽                 鏡像ID              創(chuàng)建時(shí)間            占用空間
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
hello-world         latest              2cb0d9787c4d        2 weeks ago         1.85kB