What leverage do I gain by separating discourse installation into two or more containers. E.G. for data and web.
Will there be scenarios where I want to upgrade and rebuild web container without rebuilding data container and losing all the data in DB.
Data is never lost in a rebuild, so from stated perspective you wouldn’t gain anything.
Lovely, so launcher transfers the data into a new container on a rebuild?
Per https://meta.discourse.org/t/advanced-troubleshooting-with-docker/15927, the database is actually stored outside the container(s).
AFAIK the main advantage of separating containers (if you’re changing nothing else about the default install) is reducing downtime when you’re running ./launcher rebuild app. However it’s a bit outside my knowledge and not something I’ve attempted doing, so I wouldn’t be surprised if there were more reasons to do it.
Yes, this is the main reason. You also gain flexibility; for example the ability to run the database on a separate server.