Documentation: additional explainer for the pod-selector (#4316)

docs/configs/kubernetes.md

@@ -100,6 +100,8 @@ If you are using multiple instances of homepage, an `instance` annotation can be
 
 If you have a single service that needs to be shown on multiple specific instances of homepage (but not on all of them), the service can be annotated by multiple `instance.name` annotations, where `name` can be the names of your specific multiple homepage instances. For example, a service that is annotated with `gethomepage.dev/instance.public: ""` and `gethomepage.dev/instance.internal: ""` will be shown on `public` and `internal` homepage instances.
 
+Use the `gethomepage.dev/pod-selector` selector to specify the pod used for the health check. For example, a service that is annotated with `gethomepage.dev/pod-selector: app.kubernetes.io/name=deployment` would link to a pod with the label `app.kubernetes.io/name: deployment`.
+
 ### Traefik IngressRoute support
 
 Homepage can also read ingresses defined using the Traefik IngressRoute custom resource definition. Due to the complex nature of Traefik routing rules, it is required for the `gethomepage.dev/href` annotation to be set: