The controller manager

The kube-controller manager is a single process that contains multiple controllers for simplicity. These controllers watch for events and changes to the cluster and respond accordingly:

• Node controller: Responsible for noticing and responding when nodes go down.
• Replication controller: This makes sure that there is the correct number of pods for each replica set or replication controller object.
• Endpoints controller: This assigns for each service an endpoints object that lists the service's pods.
• Service account and token controllers: These initialize new namespaces with default service accounts and corresponding API access tokens.