[Kubernetes] Track status of service based on pod events Inbox

[rgmz]

Context

Presently, the KubernetesServiceImporter tracks services 'statically':

• if a service is added, it will publish a record

• if a service is updated, it will update the record

• if a service is deleted, it will unpublish the record

Dynamic events that happen during a service's lifetime — like not having any (healthy) pods — aren't tracked, meaning the reported statuses will always be "UP". Ideally, the importer could track the lifecycle of these events to differentiate between a service that is truly "UP", versus one that merely "exists".

Describe the feature

In the OpenShift Applications > Services UI, there is a "Pods" section that shows pods associated with a service, and if they're accepting traffic:

This is seemingly accomplished by:

1. fetching a list of pods:

   
   GET /api/v1/namespaces/${NAMESPACE}/pods
   
   

2. filtering pods that match the service's selector

3. watching /api/v1/namespaces/${NAMESPACE}/pods or /api/v1/namespaces/${NAMESPACE}/events for changes (I'm not sure which; Firefox shows both, but Chrome only shows the latter)

4. GOTO 2

There are undoubtedly better approaches (e.g. Fabric8's KubernetesHelper#podsForService, but that's the one that caught my eye and inspired this issue.

The KubernetesServiceImporter could do something similar to keep track of pod events, and update the status of a service accordingly.

Use cases

• Reflects real-time status of the service

Contribution

I'd be happy to try, with some guidance. :)

[tsegismont]

Thanks for reporting this @rgmz . Please go ahead, we'll help you