Lessons Learned From Designing Serverless Apache Kafka ft. Prachetaa Raghavan

You might call building and operating Apache Kafka® as a cloud-native data service synonymous with a serverless experience. Prachetaa Raghavan (Staff Software Developer I, Confluent) spends his days focused on this very thing. In this podcast, he shares his learnings from implementing a serverless architecture on Confluent Cloud using Kubernetes Operator. 

Serverless is a cloud execution model that abstracts away server management, letting you run code on a pay-per-use basis without infrastructure concerns. Confluent Cloud's major design goal was to create a serverless Kafka solution, including handling its distributed state, its performance requirements, and seamlessly operating and scaling the Kafka brokers and Zookeeper. The serverless offering is built on top of an event-driven microservices architecture that allows you to deploy services independently with your own release cadence and maintained at the team level.

There are 4 subjects that help create the serverless event streaming experience with Kafka:

1. Confluent Cloud control plane: This Kafka-based control plane provisions resources required to run the application. It automatically scales resources for services, such as managed Kafka, managed ksqlDB, and managed connectors. The control plane and data plane are decoupled—if a single data plane has issues, it doesn’t affect the control plane or other data planes. 
2. Kubernetes Operator: The operator is an application-specific controller that extends the functionality of the Kubernetes API to create, configure, and manage instances of complex applications on behalf of Kubernetes users. The operator looks at Kafka metrics before upgrading a broker at a time. It also updates the status on cluster rebalancing and on shrink to rebalance data onto the remaining brokers. 
3. Self-Balancing Clusters: Cluster balance is measured on several dimensions, including replica counts, leader counts, disk usage, and network usage. In addition to storage rebalancing, Self-Balancing Clusters are essential to making sure that the amount of available disk and network capability is satisfied during any balancing decisions. 
4. Infinite Storage: Enabled by Tiered Storage, Infinite Storage rebalances data fast and efficiently—the most recently written data is stored directly on Kafka brokers, while older segments are moved off into a separate storage tier.  This has the added bonus of reducing the shuffling of data due to regular broker operations, like partition rebalancing.