- The rollout_status is required to get pod_names, so return nil, which
will cause the controller to return 202 or 204.
- Return additional parameters like pods, pod_name, container_name.
- pods is the names of all pods of this environment.
- Return error when no pods are available.
- pod_name is the name of the pod whose logs are being returned.
- container_name is the name of the container within the pod whose logs
are being returned. container_name can be nil when the request to k8s
API was made without a container_name.