Scaling Instances

You can scale CDAP components (instances of services and workers) using:

• the Scaling methods of the Lifecycle Microservices;

• the Get/Set Commands of the Command Line Interface; or

• the ProgramClient API of the Java Client API.

The examples given below use the Lifecycle Microservices.

Scaling Services

You can query or change the number of instances of a service by using the instances parameter with HTTP GET or PUT methods:

with the arguments as a JSON string in the body:

Examples

• Retrieve the number of instances of the service CatalogLookup in the application PurchaseHistory in the namespace default:

  GET /v3/namespaces/default/apps/PurchaseHistory/services/CatalogLookup/instances

• Set the number of handler instances of the service RetrieveCounts of the application WordCount:

  with the arguments as a JSON string in the body:

• Using curl and the CDAP Sandbox:

Scaling Workers

You can query or change the number of instances of a worker by using the instances parameter with HTTP GET or PUT methods:

with the arguments as a JSON string in the body:

Example

Retrieve the number of instances of the worker DataWorker in the application DemoApp in the namespace default: