环境：三台服务器，一台daemon可以启动，另外两台不行
解决原因：服务器内有两个docker.service，其中一个有配置--insecure-registry=127.0.0.1，重命名后启动docker可用
报错如下：
2月 23 14:43:51 ceph3 dockerd[19222]: unable to configure the Docker daemon with file /etc/docker/daemon.json: the following directives are specified both as a flag and in the configuration file: insecure-registries: (from flag: [127.0.0.1], from file: [])
2月 23 14:43:51 ceph3 systemd[1]: docker.service: main process exited, code=exited, status=1/FAILURE
2月 23 14:43:51 ceph3 systemd[1]: Failed to start Docker Application Container Engine.
2月 23 14:43:51 ceph3 systemd[1]: Unit docker.service entered failed state.
2月 23 14:43:51 ceph3 systemd[1]: docker.service failed.
2月 23 14:43:51 ceph3 systemd[1]: docker.service holdoff time over, scheduling restart.
2月 23 14:43:51 ceph3 systemd[1]: Stopped Docker Application Container Engine.
2月 23 14:43:51 ceph3 systemd[1]: start request repeated too quickly for docker.service
2月 23 14:43:51 ceph3 systemd[1]: Failed to start Docker Application Container Engine.
2月 23 14:43:51 ceph3 systemd[1]: Unit docker.service entered failed state.
2月 23 14:43:51 ceph3 systemd[1]: docker.service failed.