# cat /etc/docker/daemon.json
{
  "registry-mirrors": ["https://0nth4654.mirror.aliyuncs.com"],
  "insecure-registries": ["harbor.domain.io"]
}

[0 root@vps harbor]# cat /usr/lib/systemd/system/docker.service
[Unit]
Description=Docker Application Container Engine
Documentation=https://docs.docker.com
After=network-online.target firewalld.service containerd.service
Wants=network-online.target
Requires=docker.socket containerd.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 --insecure-registry harbor.domain.io
ExecReload=/bin/kill -s HUP $MAINPID
TimeoutSec=0
RestartSec=2
Restart=always

[0 root@vps harbor.domain.io]# docker login harbor.domain.io
Username: admin
Password:
Error response from daemon: Get https://harbor.domain.io/v2/: x509: certificate signed by unknown authority
[1 root@vps harbor.domain.io]# cp /data/secret/certs/harbor.domain.io.crt .
[0 root@vps harbor.domain.io]# docker login harbor.domain.io
Username: admin
Password:
WARNING! Your password will be stored unencrypted in /root/.docker/config.json.
Configure a credential helper to remove this warning. See
https://docs.docker.com/engine/reference/commandline/login/#credentials-store
Login Succeeded
[0 root@vps ~]# cat /root/.docker/config.json
{
	"auths": {
		"harbor.domain.io": {
			"auth": "YWRtaW46cm9vdC4xMjM0"
		}
	}
[0 root@vps harbor.domain.io]# systemctl status docker
● docker.service - Docker Application Container Engine
   Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
   Active: active (running) since Wed 2021-04-21 15:06:49 CST; 9min ago
     Docs: https://docs.docker.com
 Main PID: 32439 (dockerd)
    Tasks: 39
   Memory: 63.4M
   CGroup: /system.slice/docker.service
           ├─  920 /usr/bin/docker-proxy -proto tcp -host-ip 0.0.0.0 -host-port 443 -container-ip 172.18.0.10 -container-port 8443
           ├─  932 /usr/bin/docker-proxy -proto tcp -host-ip 0.0.0.0 -host-port 80 -container-ip 172.18.0.10 -container-port 8080
           ├─32439 /usr/bin/dockerd -H fd:// --containerd=/run/containerd/containerd.sock
           └─32646 /usr/bin/docker-proxy -proto tcp -host-ip 127.0.0.1 -host-port 1514 -container-ip 172.18.0.2 -container-port 10514
...