centos7官方镜像是没有ssh的，需要自己安装配置。
首先安装：
1 | yum install openssh* -y |
启动：
1 | usr/sbin/sshd |
发现报错如下：
1 | [root@78812d8146a9 /]# /usr/sbin/sshd |
2 | Could not load host key: /etc/ssh/ssh_host_rsa_key |
3 | Could not load host key: /etc/ssh/ssh_host_ecdsa_key |
4 | Could not load host key: /etc/ssh/ssh_host_ed25519_key |
5 | sshd: no hostkeys available -- exiting. |
所以生成秘钥：
1 | ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key -P '' |
2 | ssh-keygen -t rsa -f /etc/ssh/ssh_host_ecdsa_key -P '' |
3 | ssh-keygen -t rsa -f /etc/ssh/ssh_host_ed25519_key -P '' |
配置localhost免密：
1 | ssh-keygen -t rsa -P '' |
2 | cat ~/.ssh/id_rsa.pub >> ~/.ssh/authorized_keys |
重新启动：
1 | usr/sbin/sshd |
ssh 127.0.0.1，连接成功。