natsu@clover ~$ 
(list (build-machine
             (name "magnolia.local")
             (system "x86_64-linux")
	     (host-key "ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIMRy+enQECs2CsjrbSIfnNHExcUwzHFa7KUnhwDIeWOV")
             (user "natsu")
	     (private-key
	      (string-append (getenv "HOME")
			     "/.ssh/identity-for-guix"))
             (speed 2.)))
ssh natsu@magnolia.local -i $HOME/.ssh/identity-for-guix cat /proc/loadavg
0.05 0.08 0.02 1/247 13756