I have 2 elastic machines
M1 and M2
They both are master eligible and replicas of each other. I need to rebuild M1. But when I do that and reinstall everything on this box. M1 doesn't join back M2. I am assuming that M2 is eligible but not becoming master and may have to do with "voting rights".
How do I make it work so after a hardware and OS upgrade M1 will join M2 back and become the master and copy the data