Hi Team,

In our existing MongoDB Replica cluster , we have a 3-node replica set that was running with a configuration of priority 0.5 - 0.5 - 1.

We tried to change priority for two nodes from 0.5 to 1 to make it equivalent for all three node as "1" using rs.conf() and rs.reconfig().

But we get success in changing only one node priority from 0.5 to 1.

Even though configuration and re-configuration command successfully executed. Why not one node priority changed in configuartion.

It's showing only 0.5 and cluster priority becomes 0.5-1-1. 

Again next thing we come to notice that, one of the node which was primary in running change its priority from 1 to 2. 

We look log it's showing "Scheduling priority takeover at -----" during that time.

And finally, cluster priority becomes "2-1-0.5"  which is not our desired required output.

Kindly help us to understand the issue and why it happened.