Event delivery order for triggers - Triggers | Eventing

Configuring event delivery ordering for triggers
Next steps

In Knative Eventing, the delivery order of events plays a critical role in ensuring messages are processed according to application requirements. When using a Kafka broker, you can specify whether events should be delivered in order or without strict ordering. By configuring the delivery order, you can optimize event handling for use cases that require sequential processing or prioritize performance for unordered delivery.

Configuring event delivery ordering for triggers

If you are using a Kafka broker, you can configure the delivery order of events from triggers to event sinks.

Prerequisites

The OpenShift Serverless Operator, Knative Eventing, and Knative Kafka are installed on your OpenShift Container Platform cluster.
Kafka broker is enabled for use on your cluster, and you have created a Kafka broker.
You have created a project or have access to a project with the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform.
You have installed the OpenShift (oc) CLI.

Procedure

Create or modify a Trigger object and set the kafka.eventing.knative.dev/delivery.order annotation using the following example Trigger YAML file::
```
apiVersion: eventing.knative.dev/v1
kind: Trigger
metadata:
  name: <trigger_name>
  annotations:
     kafka.eventing.knative.dev/delivery.order: ordered
# ...
```
The supported consumer delivery guarantees are:

unordered

An unordered consumer is a non-blocking consumer that delivers messages unordered, while preserving proper offset management.

ordered

An ordered consumer is a per-partition blocking consumer that waits for a successful response from the CloudEvent subscriber before it delivers the next message of the partition.

The default ordering guarantee is unordered.
Apply the Trigger object using the following command::
```
$ oc apply -f <filename>
```

Next steps

Configure event delivery parameters that are applied in cases where an event fails to be delivered to an event sink.