This particular feature of Katapult requires that the operating system of the virtual machine in question has the Katapult agent installed. This is installed by default on all Katapult provided operating system templates. Should you have installed your own OS then this facility will not function.
Throughout the Katapult Console there are a few ways in which you can alter the various different SSH keys utilised for a given machine. The changes you make are, by default, pushed out to the machine in question via the Katapult agent. It is possible for you to enable/disable this automatic update behaviour, termed continuous management, via the SSH configuration page of a given virtual machine. Steps as follows:
Your preferences will now be saved. Should a machine be switched off it can take up to five minutes post-boot for any SSH key changes to apply.