What's your approach to databases?
What's your approach to databases?
I'm currently struggling with upgrading some Postgres DBs on my home-k3s and I'm seriously considering throwing it all away since it's such a hassle.
So, how do you handle DBs? K8s? Just a regular daemon?
You're viewing a single thread.
Are we talking database schema migrations or migrating a database between Postgres instances?
If it’s the former, the pattern is usually to run them in init containers or Jobs but I have been wanting to try out SchemaHero for a while which is a tool to orchestrate it and looks pretty neat.
ETA: Thought I was replying to your below comment but Memmy deleted it the first time for some reason, my bad.
It's about PostgreSQL upgrade.
The "pattern" there is to either dump and reinsert the entire DB or upgrade by having two installations (old and new version), which doesn't exactly work well in k8s. It's possible, but seems hacky
I can’t think of any situation other than maybe wanting to get better indexing or changing the storage engine that I would need to re-create and re-insert that way so I’m not sure if you have a constraint that necessitates that or not but now I’m curious and I am always curious to find new or better methods so why do you do it that way?
At home to upgrade Postgres I would just make a temporary copy the data directory as a backup and then just change the version of the container and if it’s needed run pg_upgrade as jobs in kubernetes.
In a work environment there is more likely to be clustering involved so the upgrade path depends on that but it’s similar but there really isn’t a need to re-create the data, the new version starts with the same PVCs using whatever rollout strategy applies. Major version upgrades can sometimes require extra steps but the engine is almost always backwards compatible at least several versions.
I've always used this docker image to do pg upgrades. It runs pg_upgrade to recreate the system tables and copy the user tables (which normally don't have any storage changes). It does require that the database isn't running during the upgrade so you're going to have a bit of downtime. Make sure you redo any changes to any configuration files, especially pg_hba.conf