The one thing I cannot find any details on, and it's not specific to Spinnaker, is; how do you perform your database changes as part of your deployment system? I figured it would be sensible to have one-off tasks you could run inside your containers as part of the pipelines, but I've not found any guidance on doing that with any CD tool at the moment.
Usually you run a database migration tool. However, the application has to be coded in a resilient way, so it can work with current and the immediate previous version.
In dev/test environments and if you have initial data that needs to be loaded, you just bring a new database up with the latest schema (hopefully in version control). You can have test cases that load old data, perform a migration and use the latest app version.
For production, it needs to be done more carefully if you're doing huge database changes. Ideally, you shouldn't exactly because CI/CD is letting you make smaller changes constantly... but sometimes your data is just too big and not trivial to migrate (e.g. a table with 1bn records now needs a new column base on data from another two columns)
