Posts Tagged ‘apachekafka’

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How to avoid SSL handshake errors in your Kafka client because of a self-signed cluster CA

Sunday, June 27th, 2021

You’re trying to connect a Kafka client to a development Apache Kafka cluster which has been quickly set up using a self-signed CA certificate. You don’t have a copy of that CA certificate, and (because it’s not signed by a well-known CA) your Kafka client is failing because of SSL handshake errors.

The error contains messages like
org.apache.kafka.common.errors.SslAuthenticationException: SSL handshake failed
and
javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target.

For example:

$ ./bin/kafka-console-consumer.sh \
 --bootstrap-server dale-kafka-saslscram-bootstrap-strimzi.apps.eem-test-fest-6.cp.fyre.ibm.com:443 \
 --topic DALE.TOPIC \
 --group dalegrp \
 --consumer-property 'security.protocol=SASL_SSL' \
 --consumer-property 'sasl.mechanism=SCRAM-SHA-512' \
 --consumer-property 'sasl.jaas.config=org.apache.kafka.common.security.scram.ScramLoginModule required username="dale-user" password="pSRtfwTMKNlz";'

[2021-06-27 23:19:06,048] ERROR [Consumer clientId=consumer-dalegrp-1, groupId=dalegrp] Connection to node -1 (dale-kafka-saslscram-bootstrap-strimzi.apps.eem-test-fest-6.cp.fyre.ibm.com/9.46.199.58:443) failed authentication due to: SSL handshake failed (org.apache.kafka.clients.NetworkClient)
[2021-06-27 23:19:06,049] WARN [Consumer clientId=consumer-dalegrp-1, groupId=dalegrp] Bootstrap broker dale-kafka-saslscram-bootstrap-strimzi.apps.eem-test-fest-6.cp.fyre.ibm.com:443 (id: -1 rack: null) disconnected (org.apache.kafka.clients.NetworkClient)
[2021-06-27 23:19:06,069] ERROR Error processing message, terminating consumer process:  (kafka.tools.ConsoleConsumer$)
org.apache.kafka.common.errors.SslAuthenticationException: SSL handshake failed
Caused by: javax.net.ssl.SSLHandshakeException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at java.base/sun.security.ssl.Alert.createSSLException(Alert.java:131)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:326)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:269)
	at java.base/sun.security.ssl.TransportContext.fatal(TransportContext.java:264)
	at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1339)
	at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.onConsumeCertificate(CertificateMessage.java:1214)
	at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.consume(CertificateMessage.java:1157)
	at java.base/sun.security.ssl.SSLHandshake.consume(SSLHandshake.java:392)
	at java.base/sun.security.ssl.HandshakeContext.dispatch(HandshakeContext.java:444)
	at java.base/sun.security.ssl.SSLEngineImpl$DelegatedTask$DelegatedAction.run(SSLEngineImpl.java:1074)
	at java.base/sun.security.ssl.SSLEngineImpl$DelegatedTask$DelegatedAction.run(SSLEngineImpl.java:1061)
	at java.base/java.security.AccessController.doPrivileged(AccessController.java:770)
	at java.base/sun.security.ssl.SSLEngineImpl$DelegatedTask.run(SSLEngineImpl.java:1008)
	at org.apache.kafka.common.network.SslTransportLayer.runDelegatedTasks(SslTransportLayer.java:430)
	at org.apache.kafka.common.network.SslTransportLayer.handshakeUnwrap(SslTransportLayer.java:514)
	at org.apache.kafka.common.network.SslTransportLayer.doHandshake(SslTransportLayer.java:368)
	at org.apache.kafka.common.network.SslTransportLayer.handshake(SslTransportLayer.java:291)
	at org.apache.kafka.common.network.KafkaChannel.prepare(KafkaChannel.java:173)
	at org.apache.kafka.common.network.Selector.pollSelectionKeys(Selector.java:543)
	at org.apache.kafka.common.network.Selector.poll(Selector.java:481)
	at org.apache.kafka.clients.NetworkClient.poll(NetworkClient.java:561)
	at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:265)
	at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:236)
	at org.apache.kafka.clients.consumer.internals.ConsumerNetworkClient.poll(ConsumerNetworkClient.java:215)
	at org.apache.kafka.clients.consumer.internals.AbstractCoordinator.ensureCoordinatorReady(AbstractCoordinator.java:244)
	at org.apache.kafka.clients.consumer.internals.ConsumerCoordinator.poll(ConsumerCoordinator.java:480)
	at org.apache.kafka.clients.consumer.KafkaConsumer.updateAssignmentMetadataIfNeeded(KafkaConsumer.java:1257)
	at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1226)
	at org.apache.kafka.clients.consumer.KafkaConsumer.poll(KafkaConsumer.java:1206)
	at kafka.tools.ConsoleConsumer$ConsumerWrapper.receive(ConsoleConsumer.scala:444)
	at kafka.tools.ConsoleConsumer$.process(ConsoleConsumer.scala:103)
	at kafka.tools.ConsoleConsumer$.run(ConsoleConsumer.scala:77)
	at kafka.tools.ConsoleConsumer$.main(ConsoleConsumer.scala:54)
	at kafka.tools.ConsoleConsumer.main(ConsoleConsumer.scala)
Caused by: sun.security.validator.ValidatorException: PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at java.base/sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:439)
	at java.base/sun.security.validator.PKIXValidator.engineValidate(PKIXValidator.java:306)
	at java.base/sun.security.validator.Validator.validate(Validator.java:264)
	at java.base/sun.security.ssl.X509TrustManagerImpl.validate(X509TrustManagerImpl.java:313)
	at java.base/sun.security.ssl.X509TrustManagerImpl.checkTrusted(X509TrustManagerImpl.java:276)
	at java.base/sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(X509TrustManagerImpl.java:141)
	at java.base/sun.security.ssl.CertificateMessage$T13CertificateConsumer.checkServerCerts(CertificateMessage.java:1317)
	... 29 more
Caused by: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target
	at java.base/sun.security.provider.certpath.SunCertPathBuilder.build(SunCertPathBuilder.java:141)
	at java.base/sun.security.provider.certpath.SunCertPathBuilder.engineBuild(SunCertPathBuilder.java:126)
	at java.base/java.security.cert.CertPathBuilder.build(CertPathBuilder.java:297)
	at java.base/sun.security.validator.PKIXValidator.doBuild(PKIXValidator.java:434)
	... 35 more
Processed a total of 0 messages

I’m assuming that this is just for development purposes, that you know it’s safe to trust the certificate that the Kafka cluster is presenting, and that you’d rather just workaround the error than ask the owner of the Kafka cluster for a copy of their CA.

(more…)

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Event Endpoint Management

Sunday, June 27th, 2021

Last week, we released the latest version of Event Endpoint Management in IBM Cloud Pak for Integration 2021.2.1. It allows organisations to share and manage access to their Kafka topics. In this post, I want to share a run-through of how it all works.

I’ll start with a high level summary overview, then a walkthrough demo video, and finally share some links to related reading if you’d like more detail.

Overview


click for a larger version of the diagram – numbers in the diagram are described below

Kafka topic owner

This is someone who has a Kafka topic, and is running an application or system that is producing a stream of events to that topic.

They think this stream of events might be useful to other developers in their organisation, so they describe it (using AsyncAPI) and publish this to a catalog where it can be discovered and managed.

  1. creates a Kafka topic and an application that produces events to it
  2. describes and documents their Kafka topic, and the events that are being produced to it
  3. publishes the description of their Kafka topic
  4. pushes the Kafka cluster security info to the Event Gateway service so it can manage access to the topic for the topic owner

App developer

This is someone who is building an application that could benefit from a stream of events.

They are able to discover the event sources that have been shared in their organisation, and get access to them through a self-service Developer Portal.

  1. creates credentials for use in their application
  2. registers new application credentials
  3. updates the Event Gateway service with the new application credentials
  4. creates or configures an application with guidance from the Portal
  5. application connects to the Event Gateway service
  6. application connection routed securely to the Kafka brokers

(more…)

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A Kafka Developer’s Guide to AsyncAPI

Tuesday, March 30th, 2021

How Kafka developers can use the AsyncAPI specification to describe how their applications are using Kafka topics.

In my post “Why should you document your Kafka topics?” last week, I wrote about the benefits of documenting your Kafka event sources, and mentioned a few of the problems that this can help with.

In this post, I want to show you how you can document the API for your Kafka event sources by creating AsyncAPI documents.

You don’t necessarily have to learn the AsyncAPI specification – tools such as the new Event Endpoint Management capability that I work on in Cloud Pak for Integration make it easy to document APIs with user-friendly forms that generate AsyncAPI documents for you. However, some developers will want to know more about what is happening under the covers, so here is an introduction.


youtu.be/Ni5tCY9r0TY

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Migrating your Apache Kafka cluster using MirrorMaker 2

Wednesday, March 24th, 2021

You have a Kafka cluster that you have been using for a while. Your cluster has many topics, and the topics have many messages.

Now you’ve decided to move and start using a new, different Kafka cluster somewhere else.

How can you take your topics with you?

Huge thanks to Andrew Borley for co-writing this with me. Useful insights in here probably came from him, the mistakes from me.

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Describing Kafka with AsyncAPI

Friday, November 27th, 2020

In this post, I want to describe how to use AsyncAPI to document how you’re using Apache Kafka. There are already great AsyncAPI “Getting Started” guides, but it supports a variety of protocols, and I haven’t found an introduction written specifically from the perspective of a Kafka user.

I’ll start with a description of what AsyncAPI is.

“an open source initiative … goal is to make working with Event-Driven Architectures as easy as it is to work with REST APIs … from documentation to code generation, from discovery to event management”

asyncapi.com/docs

The most obvious initial aspect is that it is a way to document how you’re using Kafka topics, but the impact is broader than that: a consistent approach to documentation enables an ecosystem that includes things like automated code generation and discovery.

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Using TensorFlow to make predictions from Kafka events

Sunday, September 6th, 2020

This post is a simple example of how to use a machine learning model to make predictions on a stream of events on a Kafka topic.

It’s more a quick hack than a polished project, with most of this code hacked together from samples and starter code in a single evening. But it’s a fun demo, and could be a jumping-off point for starting a more serious project.

For the purposes of a demo, I wanted to make a simple example of how to implement this pattern, using:

  • sensors that are easily and readily available, and
  • predictions that are easy to understand (and easy to generate labelled training data for)

With that goal in mind, I went with:

  • for the sensors providing the source of events, I used the accelerometer and gyroscope on my iPhone
  • to set up the Kafka broker, I used the Strimzi Kafka Operator
  • for the machine learning model, I used TensorFlow to make a simple bidirectional LSTM
  • the predictions I’m making are a description of what I’m doing with the phone (e.g. is it in my hand, is it in my pocket, etc.)

I’ve got my phone publishing a live stream of raw sensor readings, and passing that stream through an ML model to give me a live stream of events like “phone has been put on a table”, “phone has been picked up and is in my hand”, or “phone has been put in a pocket while I’m sat down”, etc.

Here is it in action. It’s a bit fiddly to demo, and a little awkward to film putting something in your pocket without filming your lap, so bear with me!

The source code is all at
github.com/dalelane/machine-learning-kafka-events.

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Supporting CI/CD with Kubernetes Operators

Thursday, August 20th, 2020

Operators bring a lot of benefits as a way of managing complex software systems in a Kubernetes cluster. In this post, I want to illustrate one in particular: the way that custom resources (and declarative approaches to managing systems in general) enable easy integration with source control and a CI/CD pipeline.

I’ll be using IBM Event Streams as my example here, but the same principles will be true for many Kubernetes Operators, in particular, the open-source Strimzi Kafka Operator that Event Streams is based on.

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Using MirrorMaker 2

Wednesday, July 15th, 2020

I’ve been talking about MirrorMaker 2 this week – the Apache Kafka tool for replicating data across two Kafka clusters. You can use it to make a copy of messages on your Kafka cluster to a remote Kafka cluster running on a different data centre, and keep that copy up to date in the background.

For the discussion we had, I needed to give examples of how you might use MirrorMaker 2, which essentially meant I spent an afternoon drawing pictures. As some of them were a little pretty, I thought I’d tidy them up and share them here.

We went through several different use cases, but I’ll just describe two examples here.
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