We migrated many instances of SQL Server 2008/R2 on Windows 2008R2 and 2012 on Windows 2012 to newer Windows 2016 with SQL Server 2014 and 2016 versions.
The old clusters were configured with either 2, 3, or 4 nodes.
Now to begin with cleaning up and decoming the Windows 2008R2 and 2012 servers, we would need to:
For 2 node clusters, uninstall SQL Server when there is no activity.
For the with 3/4 node clusters, we have one node active since application jobs are still running (just the SQL Server agent jobs running ssis packages which are already connecting to the new cluster). The migration of these jobs will take time, however. Hence I am looking for a way to break the cluster or uninstall SQL Server from the non-active nodes that will ensure the jobs continue to run on the active node.
What is the safest way to clean up the SQL Server clusters and make sure they do not break in a scenario where a single node of the 3-4 nodes needs to remain active?
Appreciate if there is any checklist one follows and can share while bringing down the SQL Server cluster.