You can login to a CentOS device on Openstack with created Private Keys. If you prefer to define username/passwords and login with these credentials too, you need to edit /etc/ssh/sshd_config file by an authorized user (e.g. root) and set the following parameters:

PasswordAuthentication yes

 

If you want to login with “root” user, you need to set the following parameter:

PermitRootLogin yes

 

If you want to disable login with public keys, you need to set the following parameter:

PubkeyAuthentication no

 

After these steps, restarting the sshd service will be enough to make all done.