AWS DMS replication task to RDS PG 2 node cluster and rds failover

Question

Hi,
I'm looking for best practice when dms replication task to an RDS 2 node cluster target 
Test case is when the target endpoint RDS performs a failover.
So writer is reader, reader is writer.
This then comes to how I configured the target endpoint.
At target endpoint creation, the option is to choose the writer node.

So upon failover from reader to writer.
How will DMS handle this.
i.e should resume work, or do I need to re-create the target endpoint to now point to the new writer.
ty

anish_g · Answer

If you are talking about Amazon RDS Multi-AZ database cluster for PostgreSQL - https://docs.aws.amazon.com/AmazonRDS/latest/UserGuide/multi-az-db-clusters-concepts.html#multi-az-db-clusters-concepts-overview, then you can use the cluster endpoint instead of individual writer instance endpoint while creating the DMS target endpoint.  So if there is a failover, the cluster endpoint will always point to the writer instance and you do not need to modify / recreate the target endpoints.  One thing to point out for Amazon RDS Multi-AZ database - 
"AWS DMS doesn't support CDC for Amazon RDS Multi-AZ database cluster for PostgreSQL as a source, since RDS for PostgreSQL Multi-AZ database clusters don't support logical replication."  Reference - https://docs.aws.amazon.com/dms/latest/userguide/CHAP_Source.PostgreSQL.html

Pushvitha · Answer

DMS takes cares of RDS failover gracefully and once the failover completed it will try to connect again to start the replication of data. Also as the replication slot is at volume level so it also not get affected from failover and as soon the secondary become primary it will connect with it and resume the task. Hence Failover itself do not cause task failure.

AWS DMS replication task to RDS PG 2 node cluster and rds failover

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