下载docker后，当需要push镜像到公司仓库或者私有仓库时，需要先login.
1. 登录时，出现了
hadoop@slave3:/etc/docker$ docker login xxxxx Username: dingheng Password: Error response from daemon: Get https:/xxxxx/: dial tcp: lookup xxxxx on 8.8.8.8:53: no such host
2. 这一看就属于DNS问题，因此需要找到linux环境下的/etc/resolv.conf
vim /etc/resolv.conf
这个nameserver 8.8.8.8出现很怪.google求之。
Editing the DNS nameserver in /etc/resolv.conf file helped me. Change your existing nameserver to google nameserver i.e., x.x.x.x to 8.8.8.8
因此直接注释改行：
3. 重启docker。
service docker restart
4. 再次login,成功。
hadoop@slave3:~$ ^C hadoop@slave3:~$ docker login xxxxx Username: dingheng Password: WARNING! Your password will be stored unencrypted in /home/hadoop/.docker/config.json. Configure a credential helper to remove this warning. See https://docs.docker.com/engine/reference/commandline/login/#credentials-store Login Succeeded hadoop@slave3:~$ docker logout