Hi @NaveenM3119: If you don't foresee any requirements for queue processors, dedicated stream node is not mandatory (but recommended to have). Also consider that OOTB queue processors will still need a stream node so that you may need to configure your batch node to serve as stream node too.

Regarding the number of nodes, it really depends on your application usage. You can work with PEGA for hardware estimation if required. (https://docs-previous.pega.com/hardware-sizing-resource-estimate)

Documentation for stream node: https://docs.pega.com/bundle/platform-88/page/platform/background-processing/queue-processor-rule-stream-node.html

Please note on the deployment architecture evolution for 3rd party services. (Externalization of services in your deployment: https://docs.pega.com/bundle/platform-88/page/platform/deployment/client-managed-cloud/externalizing-services-in-cmc-overview.html) 

Thanks.

@NaveenM3119

As per Configuring the Stream service (pega.com), 

Note:

Starting in version 8.7, the use of an internal Kafka is deprecated. On-premises systems that have been updated from earlier versions of Pega Platform™ can continue to use Kafka in embedded mode. However, to ensure future compatibility, do not create any new environments using embedded Kafka. When configuring the Stream service in a new environment, use external Kafka.

For External Kafka Implementation: Configuring External Kafka as a Stream service (pega.com)

On top of above instructions, Keeping 4-Webuser, 2-Batch and 1-Search node Types is sufficient. 

in K8's, Stream Node type use to be configured as Statefulset which is not required in the deployments such as Removing the Stream Tier configurations from Actual Deployment file.