因为网络原因，现在无法直接下载docker hub上的镜像，需设置通过proxy进行访问。
一、测试环境
在笔记本上启用了proxy软件，笔记本IP为192.168.253.1，proxy端口8888。搭建一台Linux虚拟机用于下载docker镜像，虚拟机IP：192.168.253.129
二、修改docker配置文件
修改虚拟机内docker配置文件/lib/systemd/system/docker.service，指向代理服务程序端口。
需要在Service小段中增加：
Environment="HTTP_PROXY=http://192.168.253.1:8888"
Environment="HTTPS_PROXY=http://192.168.253.1:8888"
如下：
[root@localhost ~]# vi /lib/systemd/system/docker.service
[root@localhost ~]# cat /lib/systemd/system/docker.service
[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network-online.target firewalld.service
Wants=network-online.target[Service]
Type=notify
Environment="HTTP_PROXY=http://192.168.253.1:8888"
Environment="HTTPS_PROXY=http://192.168.253.1:8888"
EnvironmentFile=-/etc/sysconfig/docker
EnvironmentFile=-/etc/sysconfig/docker-storage
EnvironmentFile=-/etc/sysconfig/docker-network
Environment=GOTRACEBACK=crashExecStart=/usr/bin/dockerd $OPTIONS \$DOCKER_STORAGE_OPTIONS \$DOCKER_NETWORK_OPTIONS \$INSECURE_REGISTRY
ExecReload=/bin/kill -s HUP $MAINPID
LimitNOFILE=1048576
LimitNPROC=1048576
LimitCORE=infinity
# set delegate yes so that systemd does not reset the cgroups of docker containers
Delegate=yes
# kill only the docker process, not all processes in the cgroup
KillMode=process[Install]
WantedBy=multi-user.target三、重启服务进行验证
[root@localhost ~]# systemctl daemon-reload
[root@localhost ~]# systemctl restart docker
[root@localhost ~]# docker pull minio/minio:latest
latest: Pulling from minio/minio
55360c0b72d6: Pull complete
f2f8f30a646a: Pull complete
4fc5fcb7e9ca: Pull complete
53140b7a7f04: Pull complete
2b8c182be72c: Pull complete
4363be478988: Pull complete
de7c323e2901: Pull complete
7eb10b7b511b: Pull complete
3d82d69301e2: Pull complete
Digest: sha256:cd04ea408e185cb50076ea1c3988d444119b19aaae15aab45387ccf14b2a2f86
Status: Downloaded newer image for minio/minio:latest
[root@localhost ~]# 可以看到，已能正常下载容器镜像，使用网络proxy也可参照配置。
