We have customised version of ISO with Ubuntu 18.04 version and it's get install without any user intervention using seed configuration. Now we have upgraded Ubuntu ISO from 18.04 to 22.04.
We have plenty of machines running with customised Ubuntu 18.04 ISO and we want to upgrade this with newly customised Ubuntu 22.04. I am trying to find a resource which help me to upgrade all the machines without any USB flash, basically want to upgrade through ssh. Could anyone please help me to understand how do I do this?