Matthias Wessendorf matzew

Event Delivery Guarantees with Knative Broker

By default the Knative Broker does a number of retry attempts based on the response code of the Addressable. The entire list is visible here.

The default is 10 reties with exponential backoff and a delay of 0.2 second. Details about the Event-Delivery knobs for the broker can be found here.

Tweaking the broker

Below is a broker that tweaks the default settings for its needs:

Event Mesh based on Knative Eventing

In Knative the Broker API is a custom Kubernetes API defining an event mesh for CloudEvents.

Creating a Knative Broker

The Broker APIs can be used as a declarative way to create broker objects, like:

apiVersion: eventing.knative.dev/v1

Assuming Strimzi is running in KAFKA namespace

This pumps date to mytopic:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: ws-dumper
spec:

Running kafkacat against Strimzi

Assumption is that you have Strimzi already running as my-cluster-kafka on the kafka namespace.

Deployment for kafkacat

Create a deployment with a recent kafkacat, like:

apiVersion: apps/v1

Stream Knative HTTP CloudEvents into Apache Kafka

With Knative eventing, you can use a source, to receive events for a 3rd party system, and have them sent as CloudEvents to a HTTP webserver, like:

apiVersion: sources.knative.dev/v1alpha2
kind: PingSource
metadata:
  name: ping-source
spec:

 k logs -f -l serving.knative.dev/service=map-display -c user-container -n debezium-knative-demo

2020-05-28 10:49:32,396 INFO  [io.sma.rea.mes.ext.MediatorManager] (main) Deployment done... start processing
2020-05-28 10:49:32,405 INFO  [io.sma.rea.mes.imp.ConfiguredChannelFactory] (main) Found incoming connectors: [smallrye-kafka]
2020-05-28 10:49:32,406 INFO  [io.sma.rea.mes.imp.ConfiguredChannelFactory] (main) Found outgoing connectors: [smallrye-kafka]
2020-05-28 10:49:32,406 INFO  [io.sma.rea.mes.imp.ConfiguredChannelFactory] (main) Stream manager initializing...
2020-05-28 10:49:32,409 INFO  [io.sma.rea.mes.ext.MediatorManager] (main) Initializing mediators
2020-05-28 10:49:32,410 INFO  [io.sma.rea.mes.ext.MediatorManager] (main) Connecting mediators
### Starting up ###

Creating Knative default Broker as non admin user

Create a consuming service:

apiVersion: serving.knative.dev/v1
kind: Service
metadata:
  name: broker-display1
spec:

	apiVersion: console.openshift.io/v1
	kind: ConsoleQuickStart
	metadata:
	name: serverless-cli
	spec:
	displayName: Serverless CLI
	description: todo
	durationMinutes: 10
	tags:
	- knative

	#!/usr/bin/env bash

	set -e

	# Turn colors in this script off by setting the NO_COLOR variable in your
	# environment to any value:
	#
	# $ NO_COLOR=1 test.sh
	NO_COLOR=${NO_COLOR:-""}
	if [ -z "$NO_COLOR" ]; then

	apiVersion: serving.knative.dev/v1
	kind: Service
	metadata:
	name: k8s-display
	spec:
	template:
	spec:
	containers:
	- image: quay.io/openshift-knative/knative-eventing-sources-event-display
	---