Fill in the user-guide for EKS migration - namespace resource changes

[poornima-krishnasamy]

Background

We have a few resources that needs amending when migrating to EKS. Add a section in the migration plan user-guide to cover those changes.

https://user-guide.cloud-platform.service.justice.gov.uk/documentation/other-topics/migrate-to-live.html#migrate-to-the-quot-live-quot-cluster

The changes include

1. Elasticsearch module changes for IRSA. For users who use elasticsearch
2. Cross account IAM roles needs moving inside environments. For users who are in https://github.com/ministryofjustice/cloud-platform-infrastructure/tree/main/terraform/cross-account-IAM. User guide for changes are here: https://user-guide.cloud-platform.service.justice.gov.uk/documentation/other-topics/access-cross-aws-resources-irsa-eks.html#use-iam-roles-for-service-accounts-to-access-resources-in-a-different-aws-account
3. Changes needs because of the ttlSecondsAfterFinished not available. Details in the ticket:live-EKS automatically remove completed Kubernetes Jobs created by a CronJob #3055

Questions:
Think of any other resources that needs amending because it is different in EKS?

Definition of done

• Migration user guide updated for sections 1,2 and 3
• another team member has reviewed
• smoke tests are green

Reference

How to write good user stories