Here we have some servers and almost each of them has a dedicated UPS. There are dependencies between them so they must be switched on in the correct sequence. Ultimately we are experiencing serious problems with the power supply, so the servers are shutdown and then restarted in a random order when power is restored. It is not a problem if the servers were switched off during a blackout, it is important they work correctly without any human intervention once power is restored.
Our UPS are quite cheap and the only configuration parameter useful for my goal is
power the load xx seconds after power is restored. In theory putting the right delays on each UPS I can fix the order of server restart but I don't trust the UPS will behave as expected.
Is it the right way to go ?
Do high level UPS give other options to fix the restart sequence ?
One final note: my Ups are in the range of 1000 - 2200 VA
systemd- the ability to define proper dependencies in the startup process. Wait until service X is available before trying to start service Y.
systemdinstance and not for services running on completely different servers...