Kubernetes Extension: Allow templating of additional kubernetes resources

[andreas-eberle]

Description

The Quarkus Kubernetes extension allows to provide custom resources to be installed alongside Quarkus via the resources/kubernetes directory (see https://quarkus.io/guides/deploying-to-kubernetes#using-existing-resources).

Unfortunately, it seems these resources cannot be templated / modified. In projects, we usually have different configurations per stage. In this case, we want to provide a CRD for a database operator and thus we want to configure it to use a larger storage in production than in the dev stage. For this, it would be great if we could use a variable syntax like ${my.field.from.application.properties} or something like that to inject fields from the application.properties into the provided kubernetes resource.

Implementation ideas

Allow using template syntax e.g. like Qute templates {my.field.from.application.properties} or something like ${my.field.from.application.properties} in the provided kubernetes resources and replace the variables with values from the application.properties.

[quarkus-bot]

/cc @geoand (kubernetes), @iocanel (kubernetes)

[geoand]

Sounds like an interesting enhancement!

Would you like to work on this?

[andreas-eberle]

I'm unsure if I can find the time to dive into this. But could you give me (or anyone else interested) a couple of hints. E.g.

• I quickly tried to figure out where exactly these resources are read and combined with the rest but didn't find it.
• And what way would you recommend to use to template the stuff? Should we use Qute? Or is there a standard mechanism to use the same variable templating like we have in the application.properties?

[geoand]

It might be that the files need to be templated in Dekorate (which Quarkus uses for the Kubernetes manifest generation). @iocanel do you remember?