[kubernetes] add replicaset pods to kubernetes.pods.running metric

[crunchie84]

In PR #2277 @masci created the basics for the pod counts based on ReplicaControllers 🏆 . Since the release of Kubernetes (k8s) 1.2 this is no longer enough. The developers introduced Deployments in k8s 1.2 which work in combination with ReplicaSets instead of ReplicaControllers thus having pods be annotated as created-by ReplicaSet.

Proposed change

The pods are grouped by creator name in /checks.d/kubernetes.py. Proposed change is to have this grouping also include pods grouped by ReplicaSet. As far as i can see the naming of ReplicationControllers/ReplicaSets is unique so no overlap should be possible.

Example annotation output with new ReplicaSets:

"annotations": {
  "kubernetes.io/created-by": "{\"kind\":\"SerializedReference\",\"apiVersion\":\"v1\",\"reference\":{\"kind\":\"ReplicaSet\",\"namespace\":\"default\",\"name\":\"myreplicaset-2962775361\",\"uid\":\"618e8a0a-07c3-11e6-855b-42010af00104\",\"apiVersion\":\"extensions\",\"resourceVersion\":\"3428\"}}\n"
}

This ticket has been created while using Kubernetes version 1.2.2

[crunchie84]

I have created a PR for the proposed change.

[pires]

Is this included in current Datadog? Using Deployments and have no data.

[therc]

I don't see this, either. Running the latest :kubernetes image. Ideally, the agent should talk to the API server and figure the desired number of replicas for a ReplicaSet or Deployment, so that you can alert if they aren't 100% running for e.g. over 5 minutes.