Building Enterprise JavaScript Applications

Scheduler

While the Discovery Service holds information about the state and location of each service, it does not make the decision of which host/node the service should be deployed on. This process is known as host selection and is the job of a scheduler:

The scheduler's decision can be based on a set of rules, called policies, which takes into account the following:

• The nature of the request.
• Cluster configuration/settings.

• Host density: An indication of how busy a the host system on the node is. If there are multiple nodes inside the cluster, we should prefer to deploy any new services on a node with the lowest host density. This information ...