AWS retires certain versions of Postgres and I'm wondering if there is anything special about Metabase/Elastibeanstalk arrangement that I need to be careful about? Cloudformation violently dislikes upgrades/changes made outside of the stack (e.g. manual upgrade of postgresql engine version), but I don't see anything in ElasticBeanstalk that would suggest the same? Is it safe to just upgrade the engine manually in RDS? Anything on the metabase side? Redeployment of the ElasticBeanstalk?
Make sure that your RDS is decoupled from EB, then you can handle them independently.
Make a backup and do the implementation you are most comfortable with. I would likely recommend setting up a new environment and just import the RDS data, but I don't run EB.
Thanks, having a clone of the environment will be required anyway (production), but I just span up a sandbox environment and did a number of upgrades without decoupling - nothing broke as far as I can tell... Will do some more testing.