移植ubuntu rootfs过程中出现ssh问题

root@kal:~# service ssh start
Job for ssh.service failed because the control process exited with error code.
See "systemctl status ssh.service" and "journalctl -xe" for details.

查看原因

root@kal:~# /usr/sbin/sshd -T
sshd: no hostkeys available -- exiting.

解决过程:
#ssh-keygen -t dsa -f /etc/ssh/ssh_host_dsa_key
#ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key

如下ok

root@kal:~# ssh-keygen -t rsa -f /etc/ssh/ssh_host_rsa_key
Generating public/private rsa key pair.

Enter passphrase (empty for no passphrase):
Enter same passphrase again:
Your identification has been saved in /etc/ssh/ssh_host_rsa_key
Your public key has been saved in /etc/ssh/ssh_host_rsa_key.pub
The key fingerprint is:
SHA256:2PQheuQ/LwNqPwz2K25AsF9xyt0ZnnJWhu7ATB38n3M root@huida
The key's randomart image is:
+---[RSA 3072]----+
|         o.o     |
|  .   . o = o    |
|   o . O++.B     |
|  . . +B*oO..    |
|   o .o S*.  . . |
|    o o....   + E|
|     o = .o    o |
|      = + oo     |
|     +.ooo o.    |
+----[SHA256]-----+
root@kal:~# /usr/sbin/sshd -T
Missing privilege separation directory: /run/sshd
root@kal:~# service ssh start
root@kal:~#