RDS: Verify and Update User Guide for DB Upgrade with Replica

[timckt]

Background

In our current user guide, it mentioned that if users are using replica db, they will need to upgrade the replica major version after upgrading the primary DB.

If you have a read replica of your database, you will also need to update the db_engine_version and rds_family attributes to your new major version after the upgrade of your primary database has finished

However, from AWS doc, it seems AWS changed the approach compared to when the user guide was written.

For Major version upgrades,

If you upgrade a DB instance that has in-Region read replicas, Amazon RDS upgrades the replicas along with the primary DB instance.

For Minor version upgrades,

If your database has read replicas, you must first upgrade all of the read replicas before you upgrade the source instance or cluster.

Verify and Update the user guide for the correct approach.

Remarks:

There are 2 DB deployments for RDS.

• Multi-AZ DB instance - resource "aws_db_instance" "default"
• Multi-AZ DB cluster - resource "aws_rds_cluster" "default"

Our RDS module is using DB instance.

Approach

Which part of the user docs does this impact

• Create the primary and replica db in the testing namespace
• Verify the correct approach with upgrading the primary and replica with no pipeline error
• Update the user guide with correct verified approach

Communicate changes

• post for #cloud-platform-update
• Weeknotes item
• Show the Thing/P&A All Hands/User CoP
• Announcements channel

Questions / Assumptions

Definition of done

• readme has been updated
• user docs have been updated
• another team member has reviewed
• smoke tests are green
• prepare demo for the team

Reference

How to write good user stories

[timckt]

This ticket shall be done asap and completed in next sprint.