> For the complete documentation index, see [llms.txt](https://daniel-guo.gitbook.io/notebook/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://daniel-guo.gitbook.io/notebook/k8s-controller-related/iscontroller-true.md).

# IsController: true

```
if err := c.Watch(&source.Kind{Type: &clusterapiv1alpha1.Cluster{}}, &handler.EnqueueRequestForOwner{
	IsController: true,
	OwnerType:    &gcmv1alpha1.ManagedCluster{},
}); err != nil {
	return err
}
```

From above, you could see there is `IsController: true` set. The [documentation](https://godoc.org/sigs.k8s.io/controller-runtime/pkg/handler#EnqueueRequestForOwner) says: **IsController if set will only look at the first OwnerReference with Controller: true.** 

Now, Let's take a look at what we have under cluster object:

```
apiVersion: cluster.k8s.io/v1alpha1
kind: Cluster
metadata:
  creationTimestamp: "2019-09-16T23:53:20Z"
  finalizers:
  - foregroundDeletion
  - cluster.cluster.k8s.io
  generation: 2
  name: test-guest-cluster-2
  namespace: default
  ownerReferences:
  - apiVersion: gcm.vmware.com/v1alpha1
    blockOwnerDeletion: true
    controller: true
    kind: ManagedCluster
    name: test-guest-cluster-2
    uid: a143951c-2ebf-4846-b9d3-adb598da2995
  ...

```

If we have `IsController: true` set in our `&handler.EnqueueRequestForOwner` . That means we are going to enqueue the name and namespace of ManagedCluster `test-guest-cluster-2` that is becuase it is the first ownerRefernce which has `controller: true` . \[To be verified: If no ownerReferences have controller:true, or only the last one has it. What will happen ?]