[linux] start faied ssh server service

$ sudo service ssh start

 * Starting OpenBSD Secure Shell server sshd

sshd: no hostkeys available -- exiting.

/etc/ssh 폴더 아래에 ssh_host_* 파일이 없어서 발생하는 문제

$ ls /etc/ssh

total 552

moduli        ssh_config            ssh_config.d              ssh_import_id

sshd_config   sshd_config.d

$

$ sudo ssh-keygen -A

ssh-keygen: generating new host keys: RSA DSA ECDSA ED25519

$ ls /etc/ssh/

moduli        ssh_host_dsa_key      ssh_host_ecdsa_key.pub    ssh_host_rsa_key      sshd_config

ssh_config    ssh_host_dsa_key.pub  ssh_host_ed25519_key      ssh_host_rsa_key.pub  sshd_config.d

ssh_config.d  ssh_host_ecdsa_key    ssh_host_ed25519_key.pub  ssh_import_id

$