26 Using the State-Change Message Bus (SCMB)

The State-Change Message Bus (SCMB) is an interface that uses asynchronous messaging to notify subscribers of changes to managed resources—both logical and physical. For example, you can program applications to receive notifications when new server hardware is added to the managed environment or when the health status of physical resources changes—without having to continuously poll the appliance for status using the REST APIs.

HP OneView resources publish messages to the SCMB when they are created, updated, or deleted. The message content is sent in JSON format and includes the resource’s Data Transfer Object.

To use the SCMB, you must:1.Use REST APIs to create and download an AMQP certificate from the appliance.2.Connect to the SCMB using one or both of these methods:Use the “EXTERNAL” authentication mechanismConnect without sending a user name and password

Using one of these methods ensures that certificate-based authentication is used.

3.Set up a queue with an empty queue name.4.AMQP generates a unique queue name.You use this queue name to bind to exchanges and receive messages.

To view the list of HP OneView resources that publish messages, see the HP OneView REST API Reference in the online help.

26.1 Connect to the SCMB

Before you connect a client to the SCMB, you must create and download an AMQP certificate from the appliance. After you connect the client to the SCMB, you can create a queue and listen for messages.

Prerequisites

Minimum required session ID privileges: Infrastructure administratorCreate and download the AMQP client certificate

Creating and downloading the client certificate, private key, and root CA certificate using REST APIs

1.Create the certificate.

POST /rest/certificates/client/rabbitmq Request body: { "commonName":"default" }

2.Download the certificate and private key.

GET /rest/certificates/client/rabbitmq/keypair/default

3.Download the root CA certificate.

GET /rest/certificates/ca

26.1 Connect to the SCMB 185