kubernetes: [GC] controller manager gets error "unable to get REST mapping for kind" for ownerRefs to TPR and add-on APIs

Is this a request for help? (If yes, you should use our troubleshooting guide and community support channels, see http://kubernetes.io/docs/troubleshooting/.):

What keywords did you search in Kubernetes issues before filing this one? (If you have found any duplicates, you should instead reply there.):

TPR. GC. OwnerReference. REST mapping.

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Is this a BUG REPORT or FEATURE REQUEST? (choose one):

BUG REPORT.

Kubernetes version (use kubectl version):

master. v1.5.1

Environment:

• Cloud provider or hardware configuration: Repro in “hack/local-up-cluster.sh”. But I have seen it in many different env.
• OS (e.g. from /etc/os-release):
• Kernel (e.g. uname -a):
• Install tools:
• Others:

What happened: The controller manager is unresponsive and overloaded with error message:

E0112 18:26:11.690849   21374 garbagecollector.go:594] Error syncing item 
&garbagecollector.node{identity:garbagecollector.objectReference{OwnerReference:v1.OwnerReference{APIVersion:"etcd.coreos.com/v1beta1", Kind:"Cluster", Name:"example-etcd-cluster", UID:"89603932-d8f4-11e6-94f3-42010af00002", Controller:(*bool)(0xc422850af8)}, Namespace:"default"}, dependentsLock:sync.RWMutex{w:sync.Mutex{state:0, sema:0x0}, writerSem:0x0, readerSem:0x0, readerCount:0, readerWait:0}, dependents:map[*garbagecollector.node]struct {}{(*garbagecollector.node)(0xc42075a6c0):struct {}{}, (*garbagecollector.node)(0xc421a0abd0):struct {}{}, (*garbagecollector.node)(0xc421c074d0):struct {}{}}, owners:[]v1.OwnerReference(nil)}: 
unable to get REST mapping for kind: Cluster, version: etcd.coreos.com/v1beta1

This error just keeps bloating up without any backoff. This seems that REST mapping didn’t recognize the kind.

What you expected to happen:

How to reproduce it (as minimally and precisely as possible):

Generic way:

• Create a TPR.
• Create a TPR object “A”
• Create pods that has OwnerReference pointing to “A”.

Easy way:

• Use https://github.com/coreos/etcd-operator
• kubectl create -f example/deployment.yaml
• kubectl create -f example/example-etcd-cluster.yaml

Anything else do we need to know: