You can configure the replication factor, bootstrap servers, and the number of topic partitions for a Kafka broker, by creating a config map and referencing this config map in the Kafka Broker
object.
Knative Eventing supports the full set of topic config options that Kafka supports. To set these options, you must add a key to the ConfigMap with the default.topic.config.
prefix.
Prerequisites
-
You have cluster or dedicated administrator permissions on OpenShift Container Platform.
-
The OpenShift Serverless Operator, Knative Eventing, and the KnativeKafka
custom resource (CR) are installed on your OpenShift Container Platform cluster.
-
You have created a project or have access to a project that has the appropriate roles and permissions to create applications and other workloads in OpenShift Container Platform.
-
You have installed the OpenShift CLI (oc
).
Procedure
-
Modify the kafka-broker-config
config map, or create your own config map that contains the following configuration:
apiVersion: v1
kind: ConfigMap
metadata:
name: <config_map_name> (1)
namespace: <namespace> (2)
data:
default.topic.partitions: <integer> (3)
default.topic.replication.factor: <integer> (4)
bootstrap.servers: <list_of_servers> (5)
default.topic.config.<config_option>: <value> (6)
1 |
The config map name. |
2 |
The namespace where the config map exists. |
3 |
The number of topic partitions for the Kafka broker. This controls how quickly events can be sent to the broker. A higher number of partitions requires greater compute resources. |
4 |
The replication factor of topic messages. This prevents against data loss. A higher replication factor requires greater compute resources and more storage. |
5 |
A comma separated list of bootstrap servers. This can be inside or outside of the OpenShift Container Platform cluster, and is a list of Kafka clusters that the broker receives events from and sends events to. |
6 |
A topic config option. For more information, see the full set of possible options and values. |
|
The default.topic.replication.factor value must be less than or equal to the number of Kafka broker instances in your cluster. For example, if you only have one Kafka broker, the default.topic.replication.factor value should not be more than "1" .
|
Example Kafka broker config map
apiVersion: v1
kind: ConfigMap
metadata:
name: kafka-broker-config
namespace: knative-eventing
data:
default.topic.partitions: "10"
default.topic.replication.factor: "3"
bootstrap.servers: "my-cluster-kafka-bootstrap.kafka:9092"
default.topic.config.retention.ms: "3600"
-
Apply the config map:
$ oc apply -f <config_map_filename>
-
Specify the config map for the Kafka Broker
object:
Example Broker object
apiVersion: eventing.knative.dev/v1
kind: Broker
metadata:
name: <broker_name> (1)
namespace: <namespace> (2)
annotations:
eventing.knative.dev/broker.class: Kafka (3)
spec:
config:
apiVersion: v1
kind: ConfigMap
name: <config_map_name> (4)
namespace: <namespace> (5)
...
1 |
The broker name. |
2 |
The namespace where the broker exists. |
3 |
The broker class annotation. In this example, the broker is a Kafka broker that uses the class value Kafka . |
4 |
The config map name. |
5 |
The namespace where the config map exists. |
-
Apply the broker:
$ oc apply -f <broker_filename>