ElastiCache URL I can hit that always uses primary node

Question

This morning I ran into an issue were my primary node in replication group was changed. I still need to investigate why this happened.

The upshot was lots of failures in a Rails application as it was trying to write to what was the primary node but had become a read replica.

Is there a URL I can use that basically says "write to the primary node of this replication group, I don't care which node that is"

Right now I am using something similar to;

name-002.aaaaa.0001.use1.cache.amazonaws.com

My "fix" for now was changing what was name-001 to name-002 but until I know the reason why the primary node was changed I have to assume this will break again.

Answer 1

I think I have answered my own question.

In the admin section for the replication group there is a Primary Endpoint which seems to do the job of delegating that work out.