03 - Centos7中安裝及驗證Docker

安裝

在Centos7中安裝Docker非常簡單，只需要一個命令：

yum -y install docker

而在Centos6的系統中安裝Docker要相對複雜一些，首先需要將系統內核版本升級到3.10以上，其次需要通過使用命令yum update等升級操作系統，具體安裝方法可參考文章《Centos 6.4中安裝Docker》。

安裝完成後需要啓動docker服務：

systemctl start docker

驗證

安裝完成後需要驗證docker服務是否安裝成功和是否正常啓動。

• 驗證版本信息

docker version

出現下面信息表示docker安裝成功及正常啓動：

[root@localhost ~]# docker version
Client:
 Version:         1.10.3
 API version:     1.22
 Package version: docker-common-1.10.3-46.el7.centos.14.x86_64
 Go version:      go1.6.3
 Git commit:      cb079f6-unsupported
 Built:           Fri Sep 16 13:24:25 2016
 OS/Arch:         linux/amd64

Server:
 Version:         1.10.3
 API version:     1.22
 Package version: docker-common-1.10.3-46.el7.centos.14.x86_64
 Go version:      go1.6.3
 Git commit:      cb079f6-unsupported
 Built:           Fri Sep 16 13:24:25 2016
 OS/Arch:         linux/amd64
[root@localhost ~]#

如果出現下面信息則表示只是安裝成功而沒有正常啓動：

[root@localhost ~]# docker version
Client:
 Version:         1.10.3
 API version:     1.22
 Package version: docker-common-1.10.3-46.el7.centos.14.x86_64
 Go version:      go1.6.3
 Git commit:      cb079f6-unsupported
 Built:           Fri Sep 16 13:24:25 2016
 OS/Arch:         linux/amd64
Cannot connect to the Docker daemon. Is the docker daemon running on this host?

此時需要輸入命令：systemctl start docker來啓動docker服務。

• 啓動容器驗證

輸入命令：docker run hello-world：

[root@localhost ~]# docker run hello-world
Unable to find image 'hello-world:latest' locally
Trying to pull repository docker.io/library/hello-world ...
latest: Pulling from docker.io/library/hello-world
c04b14da8d14: Pull complete
Digest: sha256:0256e8a36e2070f7bf2d0b0763dbabdd67798512411de4cdcf9431a1feb60fd9
Status: Downloaded newer image for docker.io/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.
 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 Hub account:
 https://hub.docker.com

For more examples and ideas, visit:
 https://docs.docker.com/engine/userguide/

出現上面信息表示安裝成功！