阿里云centos安装docker-engine实践

近日在阿里云ECS服务器（centos系统）中安装docker，参考官方指南 https://docs.docker.com/engine/installation/linux/centos/  大概流程都能跑通，但是中途发生了一些意外情况，特记录备案以免后来再次踩坑。

 

一、需要有登录ECS的工具（推荐Xshell）和拥有root权限的用户。

 

二、确保linux内核版本是3.10以上并且是64位的centos版本。如果不能满足这个前提，建议看官绕道走吧。

 

     检查linux版本命令如下

$ uname -r
3.10.-.el7.x86_64

以上前提条件都满足，接下来就开始安装。

 

三、升级yum安装包，确保都是最新的版本

 

 $  sudo yum update

四、在yum repository增加docker的repository

$  sudo vim /etc/yum.repos.d/docker.repo

## 在vim编辑器中输入以下内容后保存

[dockerrepo]
name=Docker Repository
baseurl=https://yum.dockerproject.org/repo/main/centos/$releasever/
enabled=
gpgcheck=
gpgkey=https://yum.dockerproject.org/gpg

五、到这一步都进展顺利，接下来开始通过yum安装docker-engine了。想不到的事情发生了。。。

 

 $  sudo yum install docker-engine

## yum开始从docker repository下载组件... 一切貌似进展顺利，然而突然出现一个错误

warning: /var/cache/yum/x86_64//dockerrepo/packages/docker-engine-selinux-1.10.-.el7.centos.noarch.rpm: Header V4 RSA/SHA512 Signature, key ID 2c52609d: NOKEY
Retrieving key from https://yum.dockerproject.org/gpg

GPG key retrieval failed: [Errno ] Timeout on https://yum.dockerproject.org/gpg: (28, 'Resolving timed out after 3512 milliseconds')

怎么回事？从https://yum.dockerproject.org/repo/main/centos都能顺利下载其他组件，怎么就卡在https://yum.dockerproject.org/gpg这一步呢？

ping yum.dockerproject.org 显示一切网络正常。重试几次仍然同样故障。苦苦思索和尝试仍然没有结果，最后决定先绕道吧。（有知道的同学告知一声，不胜感激）

 

绕道的办法：

 

  1. 从本机中打开https://yum.dockerproject.org/gpg，下载PKI证书文件

 

  2. 在Xshell进行以下操作 

$  sudo vim /usr/local/docker.gpg 

## 在VIM编辑器中把本地下载的证书内容复制过去，保存

-----BEGIN PGP PUBLIC KEY BLOCK-----

mQINBFWln24BEADrBl5p99uKh8+rpvqJ48u4eTtjeXAWbslJotmC/CakbNSqOb9o
ddfzRvGVeJVERt/Q/mlvEqgnyTQy+e6oEYN2Y2kqXceUhXagThnqCoxcEJ3+KM4R
mYdoe/BJ/J/6rHOjq7Omk24z2qB3RU1uAv57iY5VGw5p45uZB4C4pNNsBJXoCvPn
TGAs/7IrekFZDDgVraPx/hdiwopQ8NltSfZCyu/jPpWFK28TR8yfVlzYFwibj5WK
dHM7ZTqlA1tHIG+agyPf3Rae0jPMsHR6q+arXVwMccyOi+ULU0z8mHUJ3iEMIrpT
X+80KaN/ZjibfsBOCjcfiJSB/acn4nxQQgNZigna32velafhQivsNREFeJpzENiG
HOoyC6qVeOgKrRiKxzymj0FIMLru/iFF5pSWcBQB7PYlt8J0G80lAcPr6VCiN+4c
NKv03SdvA69dCOj79PuO9IIvQsJXsSq96HB+TeEmmL+xSdpGtGdCJHHM1fDeCqkZ
hT+RtBGQL2SEdWjxbF43oQopocT8cHvyX6Zaltn0svoGs+wX3Z/H6/8P5anog43U
65c0A+64Jj00rNDr8j31izhtQMRo892kGeQAaaxg4Pz6HnS7hRC+cOMHUU4HA7iM
zHrouAdYeTZeZEQOA7SxtCME9ZnGwe2grxPXh/U/80WJGkzLFNcTKdv+rwARAQAB
tDdEb2NrZXIgUmVsZWFzZSBUb29sIChyZWxlYXNlZG9ja2VyKSA8ZG9ja2VyQGRv
Y2tlci5jb20+iQI4BBMBAgAiBQJVpZ9uAhsvBgsJCAcDAgYVCAIJCgsEFgIDAQIe
AQIXgAAKCRD3YiFXLFJgnbRfEAC9Uai7Rv20QIDlDogRzd+Vebg4ahyoUdj0CH+n
Ak40RIoq6G26u1e+sdgjpCa8jF6vrx+smpgd1HeJdmpahUX0XN3X9f9qU9oj9A4I
1WDalRWJh+tP5WNv2ySy6AwcP9QnjuBMRTnTK27pk1sEMg9oJHK5p+ts8hlSC4Sl
uyMKH5NMVy9c+A9yqq9NF6M6d6/ehKfBFFLG9BX+XLBATvf1ZemGVHQusCQebTGv
0C0V9yqtdPdRWVIEhHxyNHATaVYOafTj/EF0lDxLl6zDT6trRV5n9F1VCEh4Aal8
L5MxVPcIZVO7NHT2EkQgn8CvWjV3oKl2GopZF8V4XdJRl90U/WDv/6cmfI08GkzD
YBHhS8ULWRFwGKobsSTyIvnbk4NtKdnTGyTJCQ8+6i52s+C54PiNgfj2ieNn6oOR
7d+bNCcG1CdOYY+ZXVOcsjl73UYvtJrO0Rl/NpYERkZ5d/tzw4jZ6FCXgggA/Zxc
jk6Y1ZvIm8Mt8wLRFH9Nww+FVsCtaCXJLP8DlJLASMD9rl5QS9Ku3u7ZNrr5HWXP
HXITX660jglyshch6CWeiUATqjIAzkEQom/kEnOrvJAtkypRJ59vYQOedZ1sFVEL
MXg2UCkD/FwojfnVtjzYaTCeGwFQeqzHmM241iuOmBYPeyTY5veF49aBJA1gEJOQ
TvBR8Q==
=Fm3p
-----END PGP PUBLIC KEY BLOCK-----

$ sudo rpm --import /usr/local/docker.gpg

3.手工导入docker的PKI公钥证书，安装总算能顺利进行下去了

 

 

六、安装docker-engine完成后，启动docker服务

 

$  sudo systemctl start docker.service

 

七、测试docker服务是否成功

 

 $  sudo docker run hello-world

##看到以下输出，就大功告成了

Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
03f4658f8b78: Pull complete
a3ed95caeb02: Pull complete
Digest: sha256:8be990ef2aeb16dbcb9271ddfe2610fa6658d13f6dfb8bc72074cc1ca36966a7
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:
 . The Docker client contacted the Docker daemon.
 . The Docker daemon pulled the "hello-world" image from the Docker Hub.
 . The Docker daemon created a new container from that image which runs the
    executable that produces the output you are currently reading.
 . 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/userguide/