Advertisement Protocol

Overview

The advertisement protocol is the logic that enables resource sharing between different clusters. It allows a cluster to make its resources available to others, in order to host their jobs, and, on the other hand, to send to and execute its applications in another cluster.

The general idea behind this protocol is to exploit periodic Advertisement messages in which a cluster exposes its capabilities. These messages are then used to build a local virtual-node where jobs can be scheduled: if a job is assigned to a virtual-node, it will be actually sent to the respective foreign cluster.

Architecture and workflow

Components

  • The broadcaster is in charge of sending to other clusters the Advertisement message, containing the resources made available for sharing and (optionally) their prices.
  • The advertisement operator (briefly called controller) is the module that receives Advertisement messages and creates the virtual nodes with the announced resources.

Workflow

Outgoing chain

  1. A foreign cluster is provided (manually by the admin or through the discovery protocol).
  2. When the foreign cluster requests some resources, the discovery logic creates the broadcaster.
  3. The broadcaster retrieves the available cluster resources and, after applying some policies, creates an Advertisement.
  4. The Advertisement is pushed to the foreign cluster.

Ingoing chain

  1. An Advertisement is received from the foreign cluster.
  2. The Advertisement is checked by a policy block: if it is accepted, it is further processed by the controller.
  3. The controller creates a virtual node with the information obtained from the Advertisement.
  4. The virtual node masquerades the foreign cluster and the resources created on it are reflected according to the sharing process.