sudo ln -sf /usr/share/zoneinfo/Asia/Seoul /etc/localtime
sudo vi /etc/hostname
docker-ubuntu.example.com
sudo vi /etc/hosts
10.100.0.105 docker-ubuntu-example.com docker-ubuntu
10.100.0.106 docker-centos-example.com docker-centos
sudo passwd root
systemctl status sshd
ssh nana@locallost