安装docker后，需要配置代理才能解决pull容器下载，具体详情如下：参考: https://cloud.tencent.com/developer/article/1806455

sudo vim /etc/systemd/system/multi-user.target.wants/docker.service
[Service]
Type=notify
# the default is not to use systemd for cgroups because the delegate issues still
# exists and systemd currently does not support the cgroup feature set required
# for containers run by docker
ExecStart=/usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
ExecReload=/bin/kill -s HUP $MAINPID
TimeoutSec=0
RestartSec=2
Restart=always
[+++]Environment="HTTP_PROXY=http://127.0.0.1:21080/"
[+++]Environment="HTTPS_PROXY=http://127.0.0.1:21080/"
[+++]Environment="NO_PROXY=localhost,127.0.0.1,.example.com"