Node Controller

!! Node Controller

The primary responsibility of the Node Controller is managing instances on its node. This includes starting and stopping and terminating instances, and also reporting on the status of instances and the capacity of the node. The Node Controller is also responsible for one end of the virtual network that provides instances with access to the outside world.

!!! Network

The Node Controller must have access to the Cluster Controller. It does not require access to the Cluster Controller, although in some setups it might. The Node Controller must also have direct access to Walrus and the Storage Controller.

!!! Interaction and Communication

The Node Controller generally receives requests from the Cluster Controller, whether it is to start or stop an instances or to query information about node capacity. The Node Controller interacts with Walrus and the Storage Controller for the purposes of managing images. It can download standard images from Walrus, or work with EBS-backed images from the Storage Controller. The Node Controller is also able to keep a cache of images.

Sources:

http://www.eucalyptus.com/sites/all/files/docs/3.0/ag.pdf

http://www.eucalyptus.com/sites/all/files/docs/3.0/ig.pdf