$ kn source list-types
You can use the following commands to list, create, and manage Knative event sources.
You can list event source types that can be created and used on your cluster by using the kn source list-types
CLI command.
The OpenShift Serverless Operator and Knative Eventing are installed on the cluster.
You have installed the Knative (kn
) CLI.
List the available event source types in the terminal:
$ kn source list-types
TYPE NAME DESCRIPTION
ApiServerSource apiserversources.sources.knative.dev Watch and send Kubernetes API events to a sink
PingSource pingsources.sources.knative.dev Periodically send ping events to a sink
SinkBinding sinkbindings.sources.knative.dev Binding for connecting a PodSpecable to a sink
Optional: On OpenShift Container Platform, you can also list the available event source types in YAML format:
$ kn source list-types -o yaml
When you create an event source by using the Knative (kn
) CLI, you can specify a sink where events are sent to from that resource by using the --sink
flag. The sink can be any addressable or callable resource that can receive incoming events from other resources.
The following example creates a sink binding that uses a service, http://event-display.svc.cluster.local
, as the sink:
$ kn source binding create bind-heartbeat \
--namespace sinkbinding-example \
--subject "Job:batch/v1:app=heartbeat-cron" \
--sink http://event-display.svc.cluster.local \ (1)
--ce-override "sink=bound"
1 | svc in http://event-display.svc.cluster.local determines that the sink is a Knative service. Other default sink prefixes include channel , and broker . |
You can use the kn source container
commands to create and manage container sources by using the Knative (kn
) CLI. Using the Knative CLI to create event sources provides a more streamlined and intuitive user interface than modifying YAML files directly.
$ kn source container create <container_source_name> --image <image_uri> --sink <sink>
$ kn source container delete <container_source_name>
$ kn source container describe <container_source_name>
$ kn source container list
$ kn source container list -o yaml
This command updates the image URI for an existing container source:
$ kn source container update <container_source_name> --image <image_uri>
You can use the kn source apiserver create
command to create an API server source by using the kn
CLI. Using the kn
CLI to create an API server source provides a more streamlined and intuitive user interface than modifying YAML files directly.
The OpenShift Serverless Operator and Knative Eventing are installed on the cluster.
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 CLI (oc
).
You have installed the Knative (kn
) CLI.
Procedure
If you want to re-use an existing service account, you can modify your existing |
Create a service account, role, and role binding for the event source as a YAML file:
apiVersion: v1
kind: serviceAccount
metadata:
name: events-sa
namespace: default (1)
---
apiVersion: rbac.authorization.k8s.io/v1
kind: Role
metadata:
name: event-watcher
namespace: default (1)
rules:
- apiGroups:
- ""
resources:
- events
verbs:
- get
- list
- watch
---
apiVersion: rbac.authorization.k8s.io/v1
kind: RoleBinding
metadata:
name: k8s-ra-event-watcher
namespace: default (1)
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: Role
name: event-watcher
subjects:
- kind: serviceAccount
name: events-sa
namespace: default (1)
1 | Change this namespace to the namespace that you have selected for installing the event source. |
Apply the YAML file:
$ oc apply -f <filename>
Create an API server source that has an event sink. In the following example, the sink is a broker:
$ kn source apiserver create <event_source_name> --sink broker:<broker_name> --resource "event:v1" --service-account <service_account_name> --mode Resource
To check that the API server source is set up correctly, create a Knative service that dumps incoming messages to its log:
$ kn service create event-display --image quay.io/openshift-knative/showcase
If you used a broker as an event sink, create a trigger to filter events from the default
broker to the service:
$ kn trigger create <trigger_name> --sink ksvc:event-display
Create events by launching a pod in the default namespace:
$ oc create deployment event-origin --image quay.io/openshift-knative/showcase
Check that the controller is mapped correctly by inspecting the output generated by the following command:
$ kn source apiserver describe <source_name>
Name: mysource
Namespace: default
Annotations: sources.knative.dev/creator=developer, sources.knative.dev/lastModifier=developer
Age: 3m
serviceAccountName: events-sa
Mode: Resource
Sink:
Name: default
Namespace: default
Kind: Broker (eventing.knative.dev/v1)
Resources:
Kind: event (v1)
Controller: false
Conditions:
OK TYPE AGE REASON
++ Ready 3m
++ Deployed 3m
++ SinkProvided 3m
++ SufficientPermissions 3m
++ EventTypesProvided 3m
To verify that the Kubernetes events were sent to Knative, look at the event-display logs or use web browser to see the events.
To view the events in a web browser, open the link returned by the following command:
$ kn service describe event-display -o url
Alternatively, to see the logs in the terminal, view the event-display logs for the pods by entering the following command:
$ oc logs $(oc get pod -o name | grep event-display) -c user-container
☁️ cloudevents.Event
Validation: valid
Context Attributes,
specversion: 1.0
type: dev.knative.apiserver.resource.update
datacontenttype: application/json
...
Data,
{
"apiVersion": "v1",
"involvedObject": {
"apiVersion": "v1",
"fieldPath": "spec.containers{event-origin}",
"kind": "Pod",
"name": "event-origin",
"namespace": "default",
.....
},
"kind": "Event",
"message": "Started container",
"metadata": {
"name": "event-origin.159d7608e3a3572c",
"namespace": "default",
....
},
"reason": "Started",
...
}
Delete the trigger:
$ kn trigger delete <trigger_name>
Delete the event source:
$ kn source apiserver delete <source_name>
Delete the service account, cluster role, and cluster binding:
$ oc delete -f authentication.yaml
You can use the kn source ping create
command to create a ping source by using the Knative (kn
) CLI. Using the Knative CLI to create event sources provides a more streamlined and intuitive user interface than modifying YAML files directly.
The OpenShift Serverless Operator, Knative Serving and Knative Eventing are installed on the cluster.
You have installed the Knative (kn
) CLI.
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.
Optional: If you want to use the verification steps for this procedure, install the OpenShift CLI (oc
).
To verify that the ping source is working, create a simple Knative service that dumps incoming messages to the service logs:
$ kn service create event-display \
--image quay.io/openshift-knative/showcase
For each set of ping events that you want to request, create a ping source in the same namespace as the event consumer:
$ kn source ping create test-ping-source \
--schedule "*/2 * * * *" \
--data '{"message": "Hello world!"}' \
--sink ksvc:event-display
Check that the controller is mapped correctly by entering the following command and inspecting the output:
$ kn source ping describe test-ping-source
Name: test-ping-source
Namespace: default
Annotations: sources.knative.dev/creator=developer, sources.knative.dev/lastModifier=developer
Age: 15s
Schedule: */2 * * * *
Data: {"message": "Hello world!"}
Sink:
Name: event-display
Namespace: default
Resource: service (serving.knative.dev/v1)
Conditions:
OK TYPE AGE REASON
++ Ready 8s
++ Deployed 8s
++ SinkProvided 15s
++ ValidSchedule 15s
++ EventTypeProvided 15s
++ ResourcesCorrect 15s
You can verify that the Kubernetes events were sent to the Knative event sink by looking at the logs of the sink pod.
By default, Knative services terminate their pods if no traffic is received within a 60 second period. The example shown in this guide creates a ping source that sends a message every 2 minutes, so each message should be observed in a newly created pod.
Watch for new pods created:
$ watch oc get pods
Cancel watching the pods using Ctrl+C, then look at the logs of the created pod:
$ oc logs $(oc get pod -o name | grep event-display) -c user-container
☁️ cloudevents.Event
Validation: valid
Context Attributes,
specversion: 1.0
type: dev.knative.sources.ping
source: /apis/v1/namespaces/default/pingsources/test-ping-source
id: 99e4f4f6-08ff-4bff-acf1-47f61ded68c9
time: 2020-04-07T16:16:00.000601161Z
datacontenttype: application/json
Data,
{
"message": "Hello world!"
}
Delete the ping source:
$ kn delete pingsources.sources.knative.dev <ping_source_name>
You can use the kn source kafka create
command to create a Kafka source by using the Knative (kn
) CLI. Using the Knative CLI to create event sources provides a more streamlined and intuitive user interface than modifying YAML files directly.
The OpenShift Serverless Operator, Knative Eventing, Knative Serving, and the KnativeKafka
custom resource (CR) are installed on your cluster.
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 access to a Red Hat AMQ Streams (Kafka) cluster that produces the Kafka messages you want to import.
You have installed the Knative (kn
) CLI.
Optional: You have installed the OpenShift CLI (oc
) if you want to use the verification steps in this procedure.
To verify that the Kafka event source is working, create a Knative service that dumps incoming events into the service logs:
$ kn service create event-display \
--image quay.io/openshift-knative/showcase
Create a KafkaSource
CR:
$ kn source kafka create <kafka_source_name> \
--servers <cluster_kafka_bootstrap>.kafka.svc:9092 \
--topics <topic_name> --consumergroup my-consumer-group \
--sink event-display
Replace the placeholder values in this command with values for your source name, bootstrap servers, and topics. |
The --servers
, --topics
, and --consumergroup
options specify the connection parameters to the Kafka cluster. The --consumergroup
option is optional.
Optional: View details about the KafkaSource
CR you created:
$ kn source kafka describe <kafka_source_name>
Name: example-kafka-source
Namespace: kafka
Age: 1h
BootstrapServers: example-cluster-kafka-bootstrap.kafka.svc:9092
Topics: example-topic
ConsumerGroup: example-consumer-group
Sink:
Name: event-display
Namespace: default
Resource: service (serving.knative.dev/v1)
Conditions:
OK TYPE AGE REASON
++ Ready 1h
++ Deployed 1h
++ SinkProvided 1h
Trigger the Kafka instance to send a message to the topic:
$ oc -n kafka run kafka-producer \
-ti --image=quay.io/strimzi/kafka:latest-kafka-2.7.0 --rm=true \
--restart=Never -- bin/kafka-console-producer.sh \
--broker-list <cluster_kafka_bootstrap>:9092 --topic my-topic
Enter the message in the prompt. This command assumes that:
The Kafka cluster is installed in the kafka
namespace.
The KafkaSource
object has been configured to use the my-topic
topic.
Verify that the message arrived by viewing the logs:
$ oc logs $(oc get pod -o name | grep event-display) -c user-container
☁️ cloudevents.Event
Validation: valid
Context Attributes,
specversion: 1.0
type: dev.knative.kafka.event
source: /apis/v1/namespaces/default/kafkasources/example-kafka-source#example-topic
subject: partition:46#0
id: partition:46/offset:0
time: 2021-03-10T11:21:49.4Z
Extensions,
traceparent: 00-161ff3815727d8755848ec01c866d1cd-7ff3916c44334678-00
Data,
Hello!