Knative CLI

Prerequisites

• OpenShift Serverless Operator and Knative Serving are installed on your 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.

Procedure

• Create a Knative service:

  $ kn service create <service-name> --image <image> --tag <tag-value>

  Where:

  • --image is the URI of the image for the application.

  • --tag is an optional flag that can be used to add a tag to the initial revision that is created with the service.

    Example command

    $ kn service create showcase \
        --image quay.io/openshift-knative/showcase

    Example output

    Creating service 'showcase' in namespace 'default':
    
      0.271s The Route is still working to reflect the latest desired specification.
      0.580s Configuration "showcase" is waiting for a Revision to become ready.
      3.857s ...
      3.861s Ingress has not yet been reconciled.
      4.270s Ready to serve.
    
    Service 'showcase' created with latest revision 'showcase-00001' and URL:
    http://showcase-default.apps-crc.testing

Example commands

• Update a service by adding a new environment variable:

  $ kn service update <service_name> --env <key>=<value>

• Update a service by adding a new port:

  $ kn service update <service_name> --port 80

• Update a service by adding new request and limit parameters:

  $ kn service update <service_name> --request cpu=500m --limit memory=1024Mi --limit cpu=1000m

• Assign the latest tag to a revision:

  $ kn service update <service_name> --tag <revision_name>=latest

• Update a tag from testing to staging for the latest READY revision of a service:

  $ kn service update <service_name> --untag testing --tag @latest=staging

• Add the test tag to a revision that receives 10% of traffic, and send the rest of the traffic to the latest READY revision of a service:

  $ kn service update <service_name> --tag <revision_name>=test --traffic test=10,@latest=90

Example commands

• Create a service:

  $ kn service apply <service_name> --image <image>

• Add an environment variable to a service:

  $ kn service apply <service_name> --image <image> --env <key>=<value>

• Read the service declaration from a JSON or YAML file:

  $ kn service apply <service_name> -f <filename>

Example commands

• Describe a service:

  $ kn service describe --verbose <service_name>

  The --verbose flag is optional but can be included to provide a more detailed description. The difference between a regular and verbose output is shown in the following examples:

  Example output without --verbose flag

  Name:       showcase
  Namespace:  default
  Age:        2m
  URL:        http://showcase-default.apps.ocp.example.com
  
  Revisions:
    100%  @latest (showcase-00001) [1] (2m)
          Image:  quay.io/openshift-knative/showcase (pinned to aaea76)
  
  Conditions:
    OK TYPE                   AGE REASON
    ++ Ready                   1m
    ++ ConfigurationsReady     1m
    ++ RoutesReady             1m

  Example output with --verbose flag

  Name:         showcase
  Namespace:    default
  Annotations:  serving.knative.dev/creator=system:admin
                serving.knative.dev/lastModifier=system:admin
  Age:          3m
  URL:          http://showcase-default.apps.ocp.example.com
  Cluster:      http://showcase.default.svc.cluster.local
  
  Revisions:
    100%  @latest (showcase-00001) [1] (3m)
          Image:  quay.io/openshift-knative/showcase (pinned to aaea76)
          Env:    GREET=Bonjour
  
  Conditions:
    OK TYPE                   AGE REASON
    ++ Ready                   3m
    ++ ConfigurationsReady     3m
    ++ RoutesReady             3m

• Describe a service in YAML format:

  $ kn service describe <service_name> -o yaml

• Describe a service in JSON format:

  $ kn service describe <service_name> -o json

• Print the service URL only:

  $ kn service describe <service_name> -o url

Prerequisites

• OpenShift Serverless Operator and Knative Serving are installed on your cluster.
• You have installed the Knative (kn) CLI.

• Add a container from an image and print it to standard output:

  $ kn container add <container_name> --image <image_uri>

  Example command

  $ kn container add sidecar --image docker.io/example/sidecar

  Example output

  containers:
  - image: docker.io/example/sidecar
    name: sidecar
    resources: {}

• Chain two kn container add commands together, and then pass them to a kn service create command to create a Knative service with two containers:

  $ kn container add <first_container_name> --image <image_uri> | \
  kn container add <second_container_name> --image <image_uri> | \
  kn service create <service_name> --image <image_uri> --extra-containers -

  --extra-containers - specifies a special case where kn reads the pipe input instead of a YAML file.

  Example command

  $ kn container add sidecar --image docker.io/example/sidecar:first | \
  kn container add second --image docker.io/example/sidecar:second | \
  kn service create my-service --image docker.io/example/my-app:latest --extra-containers -

  The --extra-containers flag can also accept a path to a YAML file:

  $ kn service create <service_name> --image <image_uri> --extra-containers <filename>

  Example command

  $ kn service create my-service --image docker.io/example/my-app:latest --extra-containers my-extra-containers.yaml

Prerequisites

• The OpenShift Serverless Operator and Knative Serving are installed on your cluster.

• You have created a Knative service or route, and control a custom domain that you want to map to that CR.

  Note

  Your custom domain must point to the DNS of the OpenShift Container Platform 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.

Procedure

• Map a domain to a CR in the current namespace:

  $ kn domain create <domain_mapping_name> --ref <target_name>

  Example command

  $ kn domain create example.com --ref showcase

  The --ref flag specifies an Addressable target CR for domain mapping.

  If a prefix is not provided when using the --ref flag, it is assumed that the target is a Knative service in the current namespace.

• Map a domain to a Knative service in a specified namespace:

  $ kn domain create <domain_mapping_name> --ref <ksvc:service_name:service_namespace>

  Example command

  $ kn domain create example.com --ref ksvc:showcase:example-namespace

• Map a domain to a Knative route:

  $ kn domain create <domain_mapping_name> --ref <kroute:route_name>

  Example command

  $ kn domain create example.com --ref kroute:example-route

Prerequisites

• The OpenShift Serverless Operator and Knative Serving are installed on your cluster.
• You have created at least one DomainMapping CR.
• You have installed the Knative (kn) CLI tool.
• 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.

Procedure

• List existing DomainMapping CRs:

  $ kn domain list -n <domain_mapping_namespace>

• View details of an existing DomainMapping CR:

  $ kn domain describe <domain_mapping_name>

• Update a DomainMapping CR to point to a new target:

  $ kn domain update --ref <target>

• Delete a DomainMapping CR:

  $ kn domain delete <domain_mapping_name>

Prerequisites

• The OpenShift Serverless Operator and Knative Eventing are installed on the cluster.
• You have installed the Knative (kn) CLI.

Prerequisites

• 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.

• To view the events in a web browser, open the link returned by the following command:

  $ kn service describe event-display -o url

  Figure 4.1. Example browser page

  

• 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

  Example output

  ☁️  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",
      ...
    }

Prerequisites

• 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).

Deleting the ping source

• Delete the ping source:

  $ kn delete pingsources.sources.knative.dev <ping_source_name>

Prerequisites

• 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.

Prerequisites

• The OpenShift Serverless Operator and Knative Serving 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.
• You must have already created and initialized the function that you want to deploy.

Procedure

• Deploy a function:

  $ kn func deploy [-n <namespace> -p <path> -i <image>]

  Example output

  Function deployed at: http://func.example.com

  • If no namespace is specified, the function is deployed in the current namespace.
  • The function is deployed from the current directory, unless a path is specified.
  • The Knative service name is derived from the project name, and cannot be changed using this command.

Procedure

• List existing functions:

  $ kn func list [-n <namespace> -p <path>]

  Example output

  NAME           NAMESPACE  RUNTIME  URL                                                                                      READY
  example-function  default    node     http://example-function.default.apps.ci-ln-g9f36hb-d5d6b.origin-ci-int-aws.dev.rhcloud.com  True

• List functions deployed as Knative services:

  $ kn service list -n <namespace>

  Example output

  NAME            URL                                                                                       LATEST                AGE   CONDITIONS   READY   REASON
  example-function   http://example-function.default.apps.ci-ln-g9f36hb-d5d6b.origin-ci-int-aws.dev.rhcloud.com   example-function-gzl4c   16m   3 OK / 3     True

Procedure

• Describe a function:

  $ kn func info [-f <format> -n <namespace> -p <path>]

  Example command

  $ kn func info -p function/example-function

  Example output

  Function name:
    example-function
  Function is built in image:
    docker.io/user/example-function:latest
  Function is deployed as Knative Service:
    example-function
  Function is deployed in namespace:
    default
  Routes:
    http://example-function.default.apps.ci-ln-g9f36hb-d5d6b.origin-ci-int-aws.dev.rhcloud.com

Prerequisites

• The OpenShift Serverless Operator and Knative Serving 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.
• You must have already deployed the function that you want to invoke.

Procedure

• Invoke a function:

  $ kn func invoke

  • The kn func invoke command only works when there is either a local container image currently running, or when there is a function deployed in the cluster.
  • The kn func invoke command executes on the local directory by default, and assumes that this directory is a function project.

Procedure

• Delete a function:

  $ kn func delete [<function_name> -n <namespace> -p <path>]

  • If the name or path of the function to delete is not specified, the current directory is searched for a func.yaml file that is used to determine the function to delete.
  • If the namespace is not specified, it defaults to the namespace value in the func.yaml file.