Database setup for k8s server
reddit / selfhosted

----------------------------------------------------------------------
p-friedrich · 2023-12-26 16:15

Hey everyone, I'm looking for some advice regarding a database setup.
I'm currently moving all my self hosted services (vaultwarden,
nextcloud, tandoor, gitlab,...) to a new server. Also, I'm switching
from docker compose to a microk8s setup with one node. So all in all a
couple of bigger changes and an opportunity to rethink previous
decisions.

With regards to databases, currently every service had it's own
database container as part of the docker compose. Now I'm unsure if
that is still a good approach or if I should rather maintain one
database instance. AFAIK all the services I use can connect to an
external Postgres db. Are there any advantages to one way or the
other? Also, would you host the database inside k8s?

----------------------------------------------------------------------
adamshand · 2023-12-26 19:30

There's no right answer, it's just trade-offs.

Using a single database for multiple services is slightly less
resource hungry and means fewer containers to manage.

Having a database per service/stack is easier to manage. Each service
has its own isolated database. You can stop, upgrade, delete, or back
it up without worrying how it affects any other service.

It bugged me when I first started using Docker, but I now much prefer
having having a database per service/stack.

----------------------------------------------------------------------
p-friedrich · 2023-12-26 20:14

Thanks for the perspective. Resources should not be an issue, the
machine I got is way too powerful as it is. I do like the greater
isolation when going one db per service. Also I probably cannot
guarantee that every service I want to use will support Postgres. So I
might have to spin up a dedicated MariaDB or similar in the future.
That would defeat the point of a single maintenance obligation.

----------------------------------------------------------------------
adamshand · 2023-12-26 20:54

That's one of the things I like, no longer trying to get everything to
work with a single database.  Just do whatever is recommended for each
app and get on with it. :-)

----------------------------------------------------------------------
PunyDev · 2023-12-27 11:56

I used to have 1 monolith postgres instance with bitnami's postgres
stack for all my services.
Switched to [CNPG](https://cloudnative-pg.io/documentation/1.21/) for
each service per database and I am loving it so far.

----------------------------------------------------------------------
ragibkl · 2023-12-27 13:55

>Also, would you host the database inside k8s?

I am doing this now. It's convenient to manage the db containers the
same way I manage the apps that use them.

You might not face any hurdles just yet with just a single k8s node,
but if you plan to have more nodes, do look into how you'll work with
persistent volumes.

I believe with docker-compose, you simply define the volumes and mount
them onto a directory inside the container. The volumes are actually
directories that live on the same host, and persist with the host.

I think you can still use a similar hostPath volume with kubernetes: [
https://kubernetes.io/docs/concepts/storage/volumes/#hostpath](https:/
/kubernetes.io/docs/concepts/storage/volumes/#hostpath), if you're
only on a single k8s node. But you might want to look into
alternatives when you play with multi node cluster.

I currently use Longhorn storage. I'm using Rancher k8s as well, so
YMMV using this on microk8s.

Also, I don't have any heavy production workload, just a homelab setup
to tinker with stuffs. Take my advice with a grain of salt.

----------------------------------------------------------------------
p-friedrich · 2023-12-28 16:47

What is the advantage of using CNPG instead of just spinning up a
database pod in each service deployment?

----------------------------------------------------------------------
p-friedrich · 2023-12-28 16:50

I went with openebs with a ZFS backend for persistent storage. Not
sure if that will provide any advantages for my use, but setting it
all up is half the fun :-)

​

>Also, I don't have any heavy production workload, just a homelab
setup to tinker with stuffs. Take my advice with a grain of salt.

most of my self hosted services have a user count of 1 XD