Sometime after 10PM tonight I will be rebooting the host machines to load new kernels and libraries. This will interrupt all services for a 10-15 minute period.
I am going to go down to the co-location facility as there are presently bugs in the systemd scripts that can cause the server to hang during shutdown. This way I can monitor it in person and if it hangs immediately force a reboot so there won’t be a prolonged interruption.
Even if the shutdown goes smoothly, it will still be 10-15 minutes because of the time it takes to save the guests before the reboot and restore them after.