Agent-wide node selector (K8s)

[zc-devs]

Clear and concise description of the problem

Allow admin to define Agent-wide node selector like it is with labels and annotations. Not using beta API or third party controllers.

See #3367.

Also from Matrix:

is there any way to set tolarations and affinity as default for pipelines in the backend for the kubernetes agent?

Although I'm about node selector, but

i would rather not fiddle around with my cluster settings to enable an alpha feature

the backend_options is basically exactly what i am looking for, but i would love to be able to specify them in the agent deployment instead of having to modify all my pipelines or remember to add that if i create a new pipeline for a new project

Maybe Cronix could define Agent-wide node selector and select Agent by labels then.

Suggested solution

Add Agent option WOODPECKER_BACKEND_K8S_POD_NODE_SELECTOR (woodpecker_backend_k8s_pod_labels)

Alternative

PodNodeSelector, v1.5 alpha.
Kyverno and similar, third party.

Additional context

No response

Validations

• Checked that the feature isn't part of the next version already [https://woodpecker-ci.org/faq#which-version-of-woodpecker-should-i-use]
• Read the docs.
• Check that there isn't already an issue that request the same feature to avoid creating a duplicate.