Configuring nodeSelector globally

[backuitist]

I have nodes on which no build workload should be scheduled. I couldn't find any way to globally configure pods. I can set the nodeSelector in the backend_options of every step but beside being very tedious it also doesn't work as some auto-generated steps like git clone won't get the proper node selector...

[zc-devs]

globally configure

You can't via Woodpecker now.

steps like git clone

Doesn't it work if you define clone step explicitly?

[backuitist]

I guess I could do that, but then every build descriptor must explicitly define the clone step in addition to specifying backend_options ...
Setting this globally seems like a reasonable feature?

[zc-devs]

can't via Woodpecker

But you can set up admission controller on namespace.

[backuitist]

Yes, I've done that but couldn't get it to work and it felt a bit hacky (resorting to plugins)... but I could revisit that and create a dedicated namespace for build workload and set it to WOODPECKER_BACKEND_K8S_NAMESPACE.
This plus setting the clone step explicitly with a nodeSelector (which then forces subsequent steps to run on the same machine), are indeed 2 viable alternatives. Perhaps they could be documented on the k8s backend admin pages. Would you take a PR?
Thanks @zc-devs

[zc-devs]

which then forces subsequent steps to run on the same machine

I suppose, it works like that only in the K3s' Local path provisioner case or something similar. But yes, it could be a hack :)

[zc-devs]

Would you take a PR?

Yes, in general. If it doesn't fit documentation format, you always have tips & tricks and blog post.

Also be aware of #3376.

[pat-s]

Alternatively, you could use https://woodpecker-ci.org/docs/administration/backends/kubernetes#woodpecker_backend_k8s_pod_labels and define some anti-toleration or affinity to prevent WP pods from getting scheduled on some nodes.