Address blue/green deployment of new database versions

[krook]

• The credentials may or may not change, but at least assume the database name does.
• Can we add a new credential key on the fly?
• Should this be in a text file that's pushed?

[jzaccone]

secrets are created at "deploy-time" and should be created by the CI/CD script. Secrets should be handled in a password manager, but we can use a text file for this POC. I guess my question is do we need to handle dynamically switching between database green and blue by changing the routing. That gets a little complicated since we have to dynamically change those keys to the new database, or create an abstraction in front that knows about both.

[krook]

Here is the proposed update process that needs to be confirmed:

Start with a v1 app and v1 db schema. As new v2 apps are deployed, they should in turn only connect to a new v2 database instance, while the v1 apps stay connected to the v1 database.

At some point there is probably a CLI worker job that handles any necessary migration after the roll in is complete, or the v1 app database goes read only once v2 apps start to be deployed.

• The first step is to migrate v1 data to a v2 database and schema to use as its baseline.
• Make the v1 database read-only and bring up the new v2 database as read/write.
• v2 apps can start to be deployed, connecting only to the v2 database.
• Once the v1 apps are completely removed and only v2 apps remain, archive the v1 database.