Confluent Developer ft. Tim Berglund, Adi Polak & Viktor Gamov

What are some recommendations to consider when running Apache Kafka® in production? Jun Rao, one of the original Kafka creators, as well as an ongoing committer and PMC member, shares the essential wisdom he's gained from developing Kafka and dealing with a large number of Kafka use cases.

Here are 6 recommendations for maximizing Kafka in production:

1. Nail Down the Operational Part
When setting up your cluster, in addition to dealing with the usual architectural issues, make sure to also invest time into alerting, monitoring, logging, and other operational concerns. Managing a distributed system can be tricky and you have to make sure that all of its parts are healthy together.  This will give you a chance at catching cluster problems early, rather than after they have become full-blown crises.

2. Reason Properly About Serialization and Schemas Up Front
At the Kafka API level, events are just bytes, which gives your application the flexibility to use various serialization mechanisms. Avro has the benefit of decoupling schemas from data serialization, whereas Protobuf is often preferable to those practiced with remote procedure calls; JSON Schema is user friendly but verbose. When you are choosing your serialization, it's a good time to reason about schemas, which should be well-thought-out contracts between your publishers and subscribers. You should know who owns a schema as well as the path for evolving that schema over time.

3. Use Kafka As a Central Nervous System Rather Than As a Single Cluster
Teams typically start out with a single, independent Kafka cluster, but they could benefit, even from the outset, by thinking of Kafka more as a central nervous system that they can use to connect disparate data sources. This enables data to be shared among more applications.

4. Utilize Dead Letter Queues (DLQs)
DLQs can keep service delays from blocking the processing of your messages. For example, instead of using a unique topic for each customer to which you need to send data (potentially millions of topics),  you may prefer to use a shared topic, or a series of shared topics that contain all of your customers. But if you are sending to multiple customers from a shared topic and one customer's REST API is down—instead of delaying the process entirely—you can have that customer's events divert into a dead letter queue. You can then process them later from that queue.

5. Understand Compacted Topics
By default in Kafka topics, data is kept by time. But there is also another type of topic, a compacted topic, which stores data by key and replaces old data with new data as it comes in. This is particularly useful for working with data that is updateable, for example, data that may be coming in through a change-data-capture log. A practical example of this would be a retailer that needs to update prices and product descriptions to send out to all of its locations.

6. Imagine New Use Cases Enabled by Kafka's Recent Evolution
The biggest recent change in Kafka's history is its migration to the cloud. By using Kafka there, you can reserve your engineering talent for business logic. The unlimited storage enabled by the cloud also means that you can truly keep data forever at reasonable cost, and thus you don't have to build a separate system for your historical data needs.

EPISODE LINKS

• Kafka Internals 101 
• Watch in video
• Kris Jenkins' Twitter
• Use PODCAST100 to get an additional $100 of free Confluent Cloud usage (details)   

SEASON 2
Hosted by Tim Berglund, Adi Polak and Viktor Gamov
Produced and Edited by Noelle Gallagher, Peter Furia and Nurie Mohamed
Music by Coastal Kites 
Artwork by Phil Vo 

•  🎧 Subscribe to Confluent Developer wherever you listen to podcasts. 
• ▶️ Subscribe on YouTube, and hit the 🔔 to catch new episodes.
• 👍 If you enjoyed this, please leave us a rating. 
• 🎧 Confluent also has a podcast for tech leaders: "Life Is But A Stream" hosted by our friend, Joseph Morais.

Is it possible to build a real-time data platform without using stateful stream processing? Forecasty.ai is an artificial intelligence platform for forecasting commodity prices, imparting insights into the future valuations of raw materials for users. Nearly all AI models are batch-trained once, but precious commodities are linked to ever-fluctuating global financial markets, which require real-time insights. In this episode, Ralph Debusmann (CTO, Forecasty.ai) shares their journey of migrating from a batch machine learning platform to a real-time event streaming system with Apache Kafka® and delves into their approach to making the transition frictionless. 

Ralph explains that Forecasty.ai was initially built on top of batch processing, however, updating the models with batch-data syncs was costly and environmentally taxing. There was also the question of scalability—progressing from 60 commodities on offer to their eventual plan of over 200 commodities. Ralph observed that most real-time systems are non-batch, streaming-based real-time data platforms with stateful stream processing, using Kafka Streams, Apache Flink®, or even Apache Samza. However, stateful stream processing involves resources, such as teams of stream processing specialists to solve the task. 

With the existing team, Ralph decided to build a real-time data platform without using any sort of stateful stream processing. They strictly keep to the out-of-the-box components, such as Kafka topics, Kafka Producer API, Kafka Consumer API, and other Kafka connectors, along with a real-time database to process data streams and implement the necessary joins inside the database. 

Additionally, Ralph shares the tool he built to handle historical data, kash.py—a Kafka shell based on Python; discusses issues the platform needed to overcome for success, and how they can make the migration from batch processing to stream processing painless for the data science team. 

EPISODE LINKS

• Kafka Streams 101 course
• The Difference Engine for Unlocking the Kafka Black Box
• GitHub repo: kash.py
• Watch the video version of this podcast
• Kris Jenkins’ Twitter
• Streaming Audio Playlist 
• Join the Confluent Community
• Learn more with Kafka tutorials, resources, and guides at Confluent Developer
• Live demo: Intro to Event-Driven Microservices with Confluent
• Use PODCAST100 to get an additional $100 of free Confluent Cloud usage (details)   

SEASON 2
Hosted by Tim Berglund, Adi Polak and Viktor Gamov
Produced and Edited by Noelle Gallagher, Peter Furia and Nurie Mohamed
Music by Coastal Kites 
Artwork by Phil Vo 

•  🎧 Subscribe to Confluent Developer wherever you listen to podcasts. 
• ▶️ Subscribe on YouTube, and hit the 🔔 to catch new episodes.
• 👍 If you enjoyed this, please leave us a rating. 
• 🎧 Confluent also has a podcast for tech leaders: "Life Is But A Stream" hosted by our friend, Joseph Morais.

Java Virtual Machines (JVMs) impact Apache Kafka® performance in production. How can you optimize your event-streaming architectures so they process more Kafka messages using the same number of JVMs? Gil Tene (CTO and Co-Founder, Azul) delves into JVM internals and how developers and architects can use Java and optimized JVMs to make real-time data pipelines more performant and more cost effective, with use cases.

Gil has deep roots in Java optimization, having started out building large data centers for parallel processing, where the goal was to get a finite set of hardware to run the largest possible number of JVMs. As the industry evolved, Gil switched his primary focus to software, and throughout the years, has gained particular expertise in garbage collection (the C4 collector) and JIT compilation. The OpenJDK distribution Gil's company Azul releases, Zulu, is widely used throughout the Java world, although Azul's Prime build version can run Kafka up to forty-percent faster than the open version—on identical hardware. 

Gil relates that improvements in JVMs aren't yielded with a single stroke or in one day, but are rather the result of many smaller incremental optimizations over time, i.e. "half-percent" improvements that accumulate. Improving a JVM starts with a good engineering team, one that has thought significantly about how to make JVMs better. The team must continuously monitor metrics, and Gil mentions that his team tests optimizations against 400-500 different workloads (one of his favorite things to get into the lab is a new customer's workload). The quality of a JVM can be measured on response times, the consistency of these response times including outliers, as well as the level and number of machines that are needed to run it. A balance between performance and cost efficiency is usually a sweet spot for customers.

Throughout the podcast, Gil goes into depth on optimization in theory and practice, as well as Azul's use of JIT compilers, as they play a key role in improving JVMs. There are always tradeoffs when using them: You want a JIT compiler to strike a balance between the work expended optimizing and the benefits that come from that work. Gil also mentions a new innovation Azul has been working on that moves JIT compilation to the cloud, where it can be applied to numerous JVMs simultaneously.

EPISODE LINKS

• A Guide on Increasing Kafka Event Streaming Performance
• Better Kafka Performance Without Changing Any Code
• Watch the video version of this podcast
• Kris Jenkins’ Twitter
• Streaming Audio Playlist 
• Join the Confluent Community
• Learn more with Kafka tutorials, resources, and guides at Confluent Developer
• Live demo: Intro to Event-Driven Microservices with Confluent
• Use PODCAST100 to get an additional $100 of free Confluent Cloud usage (details)   

SEASON 2
Hosted by Tim Berglund, Adi Polak and Viktor Gamov
Produced and Edited by Noelle Gallagher, Peter Furia and Nurie Mohamed
Music by Coastal Kites 
Artwork by Phil Vo 

•  🎧 Subscribe to Confluent Developer wherever you listen to podcasts. 
• ▶️ Subscribe on YouTube, and hit the 🔔 to catch new episodes.
• 👍 If you enjoyed this, please leave us a rating. 
• 🎧 Confluent also has a podcast for tech leaders: "Life Is But A Stream" hosted by our friend, Joseph Morais.

Apache Kafka® 3.3 is released! With over two years of development, KIP-833 marks KRaft as production ready for new AK 3.3 clusters only. On behalf of the Kafka community, Danica Fine (Senior Developer Advocate, Confluent) shares highlights of this release, with KIPs from Kafka Core, Kafka Streams, and Kafka Connect. 

To reduce request overhead and simplify client-side code, KIP-709 extends the OffsetFetch API requests to accept multiple consumer group IDs. This update has three changes, including extending the wire protocol, response handling changes, and enhancing the AdminClient to use the new protocol. 

Log recovery is an important process that is triggered whenever a broker starts up after an unclean shutdown. And since there is no way to know the log recovery progress other than checking if the broker log is busy, KIP-831 adds metrics for the log recovery progress with `RemainingLogsToRecover` and `RemainingSegmentsToRecover`for each recovery thread. These metrics allow the admin to monitor the progress of the log recovery.

Additionally, updates on Kafka Core also include KIP-841: Fenced replicas should not be allowed to join the ISR in KRaft. KIP-835: Monitor KRaft Controller Quorum Health. KIP-859: Add metadata log processing error-related metrics. 

KIP-834 for Kafka Streams added the ability to pause and resume topologies. This feature lets you reduce rescue usage when processing is not required or modifying the logic of Kafka Streams applications, or when responding to operational issues. While KIP-820 extends the KStream process with a new processor API. 

Previously, KIP-98 added support for exactly-once delivery guarantees with Kafka and its Java clients. In the AK 3.3 release, KIP-618 offers the Exactly-Once Semantics support to Confluent’s source connectors. To accomplish this, a number of new connectors and worker-based configurations have been introduced, including `exactly.once.source.support`, `transaction.boundary`, and more. 

Image attribution: Apache ZooKeeper™: https://zookeeper.apache.org/ and Raft logo:  https://raft.github.io/  

EPISODE LINKS

• See release notes for Apache Kafka 3.3.0 and Apache Kafka 3.3.1 for the full list of changes
• Read the blog to learn more
• Download Apache Kafka 3.3 and get started
• Watch the video version of this podcast

SEASON 2
Hosted by Tim Berglund, Adi Polak and Viktor Gamov
Produced and Edited by Noelle Gallagher, Peter Furia and Nurie Mohamed
Music by Coastal Kites 
Artwork by Phil Vo 

•  🎧 Subscribe to Confluent Developer wherever you listen to podcasts. 
• ▶️ Subscribe on YouTube, and hit the 🔔 to catch new episodes.
• 👍 If you enjoyed this, please leave us a rating. 
• 🎧 Confluent also has a podcast for tech leaders: "Life Is But A Stream" hosted by our friend, Joseph Morais.

How do you set data applications in motion by running stateful business logic on streaming data? Capturing key stream processing events and cumulative statistics that necessitate real-time data assessment, migration, and visualization remains as a gap—for event-driven systems and stream processing frameworks according to Fred Patton (Developer Evangelist, Swim Inc.) In this episode, Fred explains streaming applications and how it contrasts with stream processing applications. Fred and Kris also discuss how you can use Apache Kafka® and Swim for a real-time UI for streaming data.

Swim's technology facilitates relationships between streaming data from distributed sources and complex UIs, managing backpressure cumulatively, so that front ends don't get overwhelmed. They are focused on real-time, actionable insights, as opposed to those derived from historical data. Fred compares Swim's functionality to the speed layer in the Lambda architecture model, which is specifically concerned with serving real-time views. For this reason, when sending your data to Swim, it is common to also send a copy to a data warehouse that you control.

Web agent—a data entity in the Swim ecosystem, can be as small as a single cellphone or as large as a whole cellular network. Web agents communicate with one another as well as with their subscribers, and each one is a URI that can be called by a browser or the command line. Swim has been designed to instantaneously accommodate requests at widely varying levels of granularity, each of which demands a completely different volume of data. Thus, as you drill down, for example, from a city view on a map into a neighborhood view, the Swim system figures out which web agent is responsible for the view you are requesting, as well as the other web agents needed to show it.

Fred also shares an example where they work with a telephony company that requires real-time statuses for a network infrastructure with thousands of cell towers servicing millions of devices. Along with a use case for a transportation company needing to transform raw edge data into actionable insights for its connected vehicle customers. 

Future plans for Swim include porting more functionality to the cloud, which will enable additional automation, so that, for example, a customer just has to provide database and Kafka cluster connections, and Swim can automatically build out infrastructure. 

EPISODE LINKS

• Swim Cellular Network Simulator
• Continuous Intelligence - Streaming Apps That Are Always in Sync
• Using Swim with Apache Kafka
• Swim Developer
• Watch the video version of this podcast
• Kris Jenkins’ Twitter
• Streaming Audio Playlist 
• Join the Confluent Community
• Learn more with Kafka tutorials, resources, and guides at Confluent Developer
• Live demo: Intro to Event-Driven Microservices with Confluent
• Use PODCAST100 to get an additional $100 of free Confluent Cloud usage (details)   

SEASON 2
Hosted by Tim Berglund, Adi Polak and Viktor Gamov
Produced and Edited by Noelle Gallagher, Peter Furia and Nurie Mohamed
Music by Coastal Kites 
Artwork by Phil Vo 

•  🎧 Subscribe to Confluent Developer wherever you listen to podcasts. 
• ▶️ Subscribe on YouTube, and hit the 🔔 to catch new episodes.
• 👍 If you enjoyed this, please leave us a rating. 
• 🎧 Confluent also has a podcast for tech leaders: "Life Is But A Stream" hosted by our friend, Joseph Morais.

What’s your favorite podcast? Would you like to find some new ones? In celebration of International Podcast Day, Kris Jenkins invites 12 experts from the Apache Kafka® community to talk about their favorite podcasts. Unlike other episodes where guests educate developers and tell stories about Kafka, its surrounding technological ecosystem, or the Cloud, this special episode provides a glimpse into what these guests have learned through listening to podcasts that you might also find interesting. 

Through a virtual international tour, Kris chatted with Bill Bejeck (Integration Architect, Confluent), Nikoleta Verbeck (Senior Solutions Engineer, CSID, Confluent), Ben Stopford (Lead Technologist, OCTO, Confluent), Noelle Gallagher (Video Producer, Editor), Danica Fine (Senior Developer Advocate, Confluent), Tim Berglund (VP, Developer Relations, StarTree), Ben Ford (Founder and CEO, Commando Development), Jeff Bean (Group Manager, Technical Marketing, Confluent), Domenico Fioravanti (Director of Engineering, Therapie Clinic), Francesco Tisiot (Senior Developer Advocate, Aiven), Robin Moffatt (Principal, Developer Advocate, Confluent), and Simon Aubury (Principal Data Engineer, ThoughtWorks). 

They share recommendations covering a wide range of topics such as building distributed systems, travel, data engineering, greek mythology, data mesh, economics, and music and the arts.

EPISODE LINKS

• Common Apache Kafka Mistakes to Avoid
• Flink vs Kafka Streams/ksqlDB
• Why Data Mesh ft. Ben Stopford
• Practical Data Pipeline ft. Danica Fine
• What Could Go Wrong with a Kafka JDBC Connector?
• Intro to Kafka Connect: Core Components and Architecture ft. Robin Moffatt
• Serverless Stream Processing with Apache Kafka ft. Bill Bejeck
• Scaling an Apache Kafka-Based Architecture at Therapie Clinic
• Event-Driven Systems and Agile Operations
• Real-Time Stream Processing, Monitoring, and Analytics with Apache Kafka
• Watch the video version of this podcast
• Kris Jenkins’ Twitter
• Streaming Audio Playlist 
• Join the Confluent Community
• Learn more with Kafka tutorials, resources, and guides at Confluent Developer
• Use PODCAST100 to get an additional $100 of free Confluent Cloud usage (details)   

SEASON 2
Hosted by Tim Berglund, Adi Polak and Viktor Gamov
Produced and Edited by Noelle Gallagher, Peter Furia and Nurie Mohamed
Music by Coastal Kites 
Artwork by Phil Vo 

•  🎧 Subscribe to Confluent Developer wherever you listen to podcasts. 
• ▶️ Subscribe on YouTube, and hit the 🔔 to catch new episodes.
• 👍 If you enjoyed this, please leave us a rating. 
• 🎧 Confluent also has a podcast for tech leaders: "Life Is But A Stream" hosted by our friend, Joseph Morais.

How do you build an event-driven application that can react to real-time data streams as they happen? Kris Jenkins (Senior Developer Advocate, Confluent) will be hosting another fun, hands-on programming workshop—Coding in Motion: Watching the River Flow, to demonstrate how you can build a reactive event streaming application with Apache Kafka®, ksqlDB using Python.

As a developer advocate, Kris often speaks at conferences, and the presentation will be available on-demand through the organizer’s YouTube channel. The desire to read comments and be able to interact with the community motivated Kris to set up a real-time event streaming application that would notify him on his mobile phone. 

During the workshop, Kris will demonstrate the end-to-end process of using Python to process and stream data from YouTube’s REST API into a Kafka topic, analyze the data with ksqlDB, and then stream data out via Telegram. After the workshop, you’ll be able to use the recipe to build your own event-driven data application.  

EPISODE LINKS

• Coding in Motion: Building a Reactive Data Streaming App
• Watch the video version of this podcast
• Kris Jenkins’ Twitter
• Streaming Audio Playlist 
• Join the Confluent Community
• Learn more with Kafka tutorials, resources, and guides at Confluent Developer
• Live demo: Intro to Event-Driven Microservices with Confluent
• Use PODCAST100 to get an additional $100 of free Confluent Cloud usage (details)   

SEASON 2
Hosted by Tim Berglund, Adi Polak and Viktor Gamov
Produced and Edited by Noelle Gallagher, Peter Furia and Nurie Mohamed
Music by Coastal Kites 
Artwork by Phil Vo 

•  🎧 Subscribe to Confluent Developer wherever you listen to podcasts. 
• ▶️ Subscribe on YouTube, and hit the 🔔 to catch new episodes.
• 👍 If you enjoyed this, please leave us a rating. 
• 🎧 Confluent also has a podcast for tech leaders: "Life Is But A Stream" hosted by our friend, Joseph Morais.

Processing real-time event streams enables countless use cases big and small. With a day job designing and building highly available distributed data systems, Simon Aubury (Principal Data Engineer, Thoughtworks) believes stream-processing thinking can be applied to any stream of events. 

In this episode, Simon shares his Confluent Hackathon ’22 winning project—a wildlife monitoring system to observe population trends over time using a Raspberry Pi, along with Apache Kafka®, Kafka Connect, ksqlDB, TensorFlow Lite, and Kibana. He used the system to count animals in his Australian backyard and perform trend analysis on the results. Simon also shares ideas on how you can use these same technologies to help with other real-world challenges.

Open-source, object detection models for TensorFlow, which appropriately are collected into "model zoos," meant that Simon didn't have to provide his own object identification as part of the project, which would have made it untenable. Instead, he was able to utilize the open-source models, which are essentially neural nets pretrained on relevant data sets—in his case, backyard animals.

Simon's system, which consists of around 200 lines of code, employs a Kafka producer running a while loop, which connects to a camera feed using a Python library. For each frame brought down, object masking is applied in order to crop and reduce pixel density, and then the frame is compared to the models mentioned above. A Python dictionary containing probable found objects is sent to a Kafka broker for processing; the images themselves aren't sent. (Note that Simon's system is also capable of alerting if a specific, rare animal is detected.) 

On the broker, Simon uses ksqlDB and windowing to smooth the data in case the frames were inconsistent for some reason (it may look back over thirty seconds, for example, and find the highest number of animals per type). Finally, the data is sent to a Kibana dashboard for analysis, through a Kafka Connect sink connector. 

Simon’s system is an extremely low-cost system that can simulate the behaviors of more expensive, proprietary systems. And the concepts can easily be applied to many other use cases. For example, you could use it to estimate traffic at a shopping mall to gauge optimal opening hours, or you could use it to monitor the queue at a coffee shop, counting both queued patrons as well as impatient patrons who decide to leave because the queue is too long.

EPISODE LINKS

• Real-Time Wildlife Monitoring with Apache Kafka
• Wildlife Monitoring Github
• ksqlDB Fundamentals: How Apache Kafka, SQL, and ksqlDB Work Together
• Event-Driven Architecture - Common Mistakes and Valuable Lessons
• Motion in Motion: Building an End-to-End Motion Detection and Alerting System with Apache Kafka and ksqlDB
• Watch the video version of this podcast
• Kris Jenkins’ Twitter
• Learn more on Confluent Developer
• Use PODCAST100 to get $100 of free Confluent Cloud usage (details)   

SEASON 2
Hosted by Tim Berglund, Adi Polak and Viktor Gamov
Produced and Edited by Noelle Gallagher, Peter Furia and Nurie Mohamed
Music by Coastal Kites 
Artwork by Phil Vo 

•  🎧 Subscribe to Confluent Developer wherever you listen to podcasts. 
• ▶️ Subscribe on YouTube, and hit the 🔔 to catch new episodes.
• 👍 If you enjoyed this, please leave us a rating. 
• 🎧 Confluent also has a podcast for tech leaders: "Life Is But A Stream" hosted by our friend, Joseph Morais.

How do you analyze Reddit sentiment with Apache Kafka® and microservices? Bringing the fresh perspective of someone who is both new to Kafka and the industry, Shufan Liu, nascent Developer Advocate at Confluent, discusses projects he has worked on during his summer internship—a Cluster Linking extension to a conceptual data pipeline project, and a microservice-based Reddit sentiment-analysis project. Shufan demonstrates that it’s possible to quickly get up to speed with the tools in the Kafka ecosystem and to start building something productive early on in your journey.

Shufan's Cluster Linking project extends a demo by Danica Fine (Senior Developer Advocate, Confluent) that uses a Kafka-based data pipeline to address the challenge of automatic houseplant watering. He discusses his contribution to the project and shares details in his blog—Data Enrichment in Existing Data Pipelines Using Confluent Cloud.

The second project Shufan presents is a sentiment analysis system that gathers data from a given subreddit, then assigns the data a sentiment score. He points out that its results would be hard to duplicate manually by simply reading through a subreddit—you really need the assistance of AI. The project consists of four microservices:

1. A user input service that collects requests in a Kafka topic, which consist of the desired subreddit, along with the dates between which data should be collected
2. An API polling service that fetches the requests from the user input service, collects the relevant data from the Reddit API, then appends it to a new topic
3. A sentiment analysis service that analyzes the appended topic from the API polling service using the Python library NLTK; it calculates averages with ksqlDB
4. A results-displaying service that consumes from a topic with the calculations

Interesting subreddits that Shufan has analyzed for sentiment include gaming forums before and after key releases; crypto and stock trading forums at various meaningful points in time; and sports-related forums both before the season and several games into it. 

EPISODE LINKS

• Data Enrichment in Existing Data Pipelines Using Confluent Cloud
• Watch the video version of this podcast
• Kris Jenkins’ Twitter
• Streaming Audio Playlist 
• Join the Confluent Community
• Learn more with Kafka tutorials, resources, and guides at Confluent Developer
• Live demo: Intro to Event-Driven Microservices with Confluent
• Use PODCAST100 to get an additional $100 of free Confluent Cloud usage (details) 

SEASON 2
Hosted by Tim Berglund, Adi Polak and Viktor Gamov
Produced and Edited by Noelle Gallagher, Peter Furia and Nurie Mohamed
Music by Coastal Kites 
Artwork by Phil Vo 

•  🎧 Subscribe to Confluent Developer wherever you listen to podcasts. 
• ▶️ Subscribe on YouTube, and hit the 🔔 to catch new episodes.
• 👍 If you enjoyed this, please leave us a rating. 
• 🎧 Confluent also has a podcast for tech leaders: "Life Is But A Stream" hosted by our friend, Joseph Morais.

How do you plan Apache Kafka® capacity and Kafka Streams sizing for optimal performance? 

When Jason Bell (Principal Engineer, Dataworks and founder of Synthetica Data), begins to plan a Kafka cluster, he starts with a deep inspection of the customer's data itself—determining its volume as well as its contents: Is it JSON, straight pieces of text, or images? He then determines if Kafka is a good fit for the project overall, a decision he bases on volume, the desired architecture, as well as potential cost.

Next, the cluster is conceived in terms of some rule-of-thumb numbers. For example, Jason's minimum number of brokers for a cluster is three or four. This means he has a leader, a follower and at least one backup.  A ZooKeeper quorum is also a set of three. For other elements, he works with pairs, an active and a standby—this applies to Kafka Connect and Schema Registry. Finally, there's Prometheus monitoring and Grafana alerting to add. Jason points out that these numbers are different for multi-data-center architectures.

Jason never assumes that everyone knows how Kafka works, because some software teams include specialists working on a producer or a consumer, who don't work directly with Kafka itself. They may not know how to adequately measure their Kafka volume themselves, so he often begins the collaborative process of graphing message volumes. He considers, for example, how many messages there are daily, and whether there is a peak time. Each industry is different, with some focusing on daily batch data (banking), and others fielding incredible amounts of continuous data (IoT data streaming from cars).  

Extensive testing is necessary to ensure that the data patterns are adequately accommodated. Jason sets up a short-lived system that is identical to the main system. He finds that teams usually have not adequately tested across domain boundaries or the network. Developers tend to think in terms of numbers of messages, but not in terms of overall network traffic, or in how many consumers they'll actually need, for example. Latency must also be considered, for example if the compression on the producer's side doesn't match compression on the consumer's side, it will increase.

Kafka Connect sink connectors require special consideration when Jason is establishing a cluster. Failure strategies need to well thought out, including retries and how to deal with the potentially large number of messages that can accumulate in a dead letter queue. He suggests that more attention should generally be paid to the Kafka Connect elements of a cluster, something that can actually be addressed with bash scripts.

Finally, Kris and Jason cover his preference for Kafka Streams over ksqlDB from a network perspective. 

EPISODE LINKS

• Capacity Planning and Sizing for Kafka Streams
• Tales from the Frontline of Apache Kafka DevOps
• Watch the video version of this podcast
• Kris Jenkins’ Twitter
• Streaming Audio Playlist 
• Join the Confluent Community
• Learn more on Confluent Developer
• Use PODCAST100 to get $100 of free Cloud usage (details)  

SEASON 2
Hosted by Tim Berglund, Adi Polak and Viktor Gamov
Produced and Edited by Noelle Gallagher, Peter Furia and Nurie Mohamed
Music by Coastal Kites 
Artwork by Phil Vo 

•  🎧 Subscribe to Confluent Developer wherever you listen to podcasts. 
• ▶️ Subscribe on YouTube, and hit the 🔔 to catch new episodes.
• 👍 If you enjoyed this, please leave us a rating. 
• 🎧 Confluent also has a podcast for tech leaders: "Life Is But A Stream" hosted by our friend, Joseph Morais.