RDS Snapshot debugging for migrated DB scenarios

[sj-williams]

Background

We have a team migrating databases using shared snapshots

In the case where a team is wanting to use a shared Oracle RDS snapshot in CP account from external account, after sharing, copying and using new KMS key, the new instance created using snapshot always wants to recreate.

In testing we have observed that setting the module username param to null will passthru the snapshops existing DB username, and does not attempt to recreate DB on second run.

Create a branch with an optional username field for the module, overriding the random generated username, and have Oracle team test using this modified RDS module settings to test their Oracle DB migration, does everything work as expected?

If this change resolves force recreate issues and database functions as expected, publish module update and update user-guide entry for snapshop migration workflow.

Proposed user journey

Approach

Which part of the user docs does this impact

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

[sj-williams]

rds module branch

https://github.com/ministryofjustice/cloud-platform-terraform-rds-instance/tree/migration

[sj-williams]

Changes introduced on test branch so far:

is_migration optional input which, when enabled, along with snapshot_identifier set:

• allows snapshop db username to be persisted into new instance
• utilises a snapshot copy terraform resource to create new copy of shared migration snapshop, with the module instance specific kms key to override that of the snapshot copy

Testing of CCLF and CCR migrated Oracle DBs using the above method appears to be working with dev application connections and port-forward DB client connection checks.