I'm planning to do an in-place upgrade of our SQL 2008 R2 Failover Cluster to 2012. If any of you have done this already, would you care to share?
Steps I've in mind:
1. Pause or evict (?) the passive node from the cluster
2. Upgrade Windows 2008 R2 to Windows 2012 - reboot the server?
3. Upgrade SQL 2008 R2 to SQL server 2012
4. Restart the node
5. Make sure Failover Cluster settings are intact.
6. Failover cluster to this passive node (passive will then become active node)
7. Repeat #1 - 5 until the other node is upgraded
8. Test failover and failbacks few times.
9. Check database connectivity
There may be some steps in between the above steps to carry out that I have no knowledge about. Please let me know what they are!