How to enable passwordless logins to a server

  1. Enable root login with password on the server. To do so, you need to edit the file /etc/ssh/sshd_config.
    Modify the lines starting with "PermitRootLogin" like this:
    #PermitRootLogin prohibit-password
    PermitRootLogin yes
  2. Restart the sshd server:
    sudo systemctl restart sshd
  3. On the client, copy the public key files to the server with the ssh-copy-id command:
    ssh-copy-id root@server
  4. On the server, disable root login with password and enable root login with public key authentication:

Is Ubuntu 18.04 still using the SSD drive for swap?

In an Ubuntu 18.04 two disk setup (/ on SSD, /home on spinning drive), my Ubuntu 18.04 has still defaulted to use swap space on the SSD although there was a swap partition of the same size on the spinning drive. This was not a new install, but a system upgrade from 16.04 (where I had created a swap partition manually on the spinning drive to spare the SSD). Linux is able to determine whether a drive is spinning or not, but apparently the installation/upgrade script was not very smart.