[sudo] passoword for user:
*starting OpenBSD Secure Shell server sshd
sshd: no hostkeys availble -- exiting.

On another linux host, 4.18.0-147.8.1.el8_1.x86_64, we have the files

/etc/ssh/ssh_host_ed25519_key
/etc/ssh/ssh_host_ed25519_key.pub
/etc/ssh/ssh_host_ecdsa_key
/etc/ssh/ssh_host_rsa_key.pub
/etc/ssh/ssh_host_ecdsa_key.pub
/etc/ssh/ssh_host_rsa_key