在CentOS 7中安装Docker

1-确认系统信息

# cat /etc/redhat-release
CentOS Linux release 7.2.1511 (Core)
# uname -a
Linux CentOS-7 3.10.0-327.el7.x86_64 #1 SMP Thu Nov 19 22:10:57 UTC 2015 x86_64 x86_64 x86_64 GNU/Linux

2-安装docker

# yum -y install docker

3-关闭SELinux和启动docker服务

关闭SELinux

• 永久方法：修改/etc/selinux/config文件中设置SELINUX=disabled ，然后重启。
• 临时方法：执行setenforce 0命令设置SELinux成为permissive模式

sudo systemctl status firewalld.service
sudo systemctl stop firewalld.service
sudo systemctl disable firewalld.service

启动docker服务
[root@CentOS-7 ~]# systemctl start docker.service

设置自启动docker服务

[root@CentOS-7 ~]# systemctl enable docker.service
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@CentOS-7 ~]# systemctl is-enabled docker.service
enabled
[root@CentOS-7 ~]# 

4-设置docker代理

# vim /etc/sysconfig/docker
根据实际需要添加相应内容

HTTP_PROXY=http://10.144.1.10:8080
#HTTPS_PROXY=https://10.144.1.10:8080
#FTP_PROXY=ftp://10.144.1.10:8080

注意：一般情况下，国内镜像设置或代理设置，只需要完成一种配置就可以了。

5-重启docker

# systemctl daemon-reload
# systemctl restart docker

6-安装验证

运行官方镜像hello-world文件

# 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:latestHello 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 theexecutable that produces the output you are currently reading.4. The Docker daemon streamed that output to the Docker client, which sent itto your terminal.To try something more ambitious, you can run an Ubuntu container with:$ docker run -it ubuntu bashShare images, automate workflows, and more with a free Docker Hub account:https://hub.docker.comFor more examples and ideas, visit:https://docs.docker.com/engine/userguide/#
# docker images
REPOSITORY              TAG                 IMAGE ID            CREATED             SIZE
docker.io/hello-world   latest              c54a2cc56cbb        5 months ago        1.848 kB

另外一种Docker代理设置方法

修改docker.service文件
# vim /usr/lib/systemd/system/docker.service
在[Service]部分添加如下内容
Environment="HTTP_PROXY=http://10.144.1.10:8080"
Environment="HTTPS_PROXY=https://10.144.1.10:8080"
Environment="FTP_PROXY=ftp://10.144.1.10:8080"

或者，另外创建代理文件

# mkdir /etc/systemd/system/docker.service.d
# touch /etc/systemd/system/docker.service.d/proxy.conf
# vim /etc/systemd/system/docker.service.d/proxy.conf

增加以下内容
[Service]
Environment="HTTP_PROXY=http://10.144.1.10:8080"
Environment="HTTPS_PROXY=https://10.144.1.10:8080"
Environment="FTP_PROXY=ftp://10.144.1.10:8080"

重启docker
# systemctl daemon-reload
# systemctl restart docker

检查docker环境变量是否加载

# systemctl show docker --property Environment
Environment=GOTRACEBACK=crash HTTP_PROXY=http://10.144.1.10:8080 HTTPS_PROXY=https://10.144.1.10:8080 FTP_PROXY=ftp://10.144.1.10:8080

示例 - 在CentOS7系统安装docker并运行镜像（使用国内镜像）

[root@CentOS7 ~]# route add default gw 10.0.3.2
[root@CentOS7 ~]#
[root@CentOS7 ~]# yum -y install docker

[root@CentOS7 ~]# vim /etc/selinux/config
[root@CentOS7 ~]#  cat /etc/selinux/config |grep "SELINUX="
# SELINUX= can take one of these three values:
SELINUX=disabled
[root@CentOS7 ~]#
[root@CentOS7 ~]# setenforce 0
[root@CentOS7 ~]#
[root@CentOS7 ~]# systemctl start docker.service
[root@CentOS7 ~]# systemctl enable docker.service
Created symlink from /etc/systemd/system/multi-user.target.wants/docker.service to /usr/lib/systemd/system/docker.service.
[root@CentOS7 ~]# systemctl is-enabled docker.service
enabled
[root@CentOS7 ~]#
[root@CentOS7 ~]# sudo mkdir -p /etc/docker
[root@CentOS7 ~]# sudo tee /etc/docker/daemon.json <<-'EOF'
> {
>   "registry-mirrors": ["https://t5t8q6wn.mirror.aliyuncs.com"]
> }
> EOF
{"registry-mirrors": ["https://t5t8q6wn.mirror.aliyuncs.com"]
}
[root@CentOS7 ~]# systemctl daemon-reload
[root@CentOS7 ~]# systemctl restart docker
[root@CentOS7 ~]#
[root@CentOS7 ~]# docker images
REPOSITORY          TAG                 IMAGE ID            CREATED             SIZE
[root@CentOS7 ~]#
[root@CentOS7 ~]# 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
78445dd45222: Pull complete
Digest: sha256:c5515758d4c5e1e838e9cd307f6c6a0d620b5e07e6f927b07d05f6d12a1ac8d7Hello 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 theexecutable that produces the output you are currently reading.4. The Docker daemon streamed that output to the Docker client, which sent itto your terminal.To try something more ambitious, you can run an Ubuntu container with:$ docker run -it ubuntu bashShare images, automate workflows, and more with a free Docker ID:https://cloud.docker.com/For more examples and ideas, visit:https://docs.docker.com/engine/userguide/[root@CentOS7 ~]#
[root@CentOS7 ~]# docker images
REPOSITORY              TAG                 IMAGE ID            CREATED             SIZE
docker.io/hello-world   latest              48b5124b2768        3 months ago        1.84 kB
[root@CentOS7 ~]#