$ kn service create <service-name> --image <image> --tag <tag-value>
You can use the following commands to create and manage Knative services.
Using the Knative (kn
) CLI to create serverless applications provides a more streamlined and intuitive user interface over modifying YAML files directly. You can use the kn service create
command to create a basic serverless application.
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.
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.
$ kn service create showcase \
--image quay.io/openshift-knative/showcase
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
You can use the kn service update
command for interactive sessions on the command line as you build up a service incrementally. In contrast to the kn service apply
command, when using the kn service update
command you only have to specify the changes that you want to update, rather than the full configuration for the Knative service.
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
You can declaratively configure a Knative service by using the kn service apply
command. If the service does not exist it is created, otherwise the existing service is updated with the options that have been changed.
The kn service apply
command is especially useful for shell scripts or in a continuous integration pipeline, where users typically want to fully specify the state of the service in a single command to declare the target state.
When using kn service apply
you must provide the full configuration for the Knative service. This is different from the kn service update
command, which only requires you to specify in the command the options that you want to update.
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>
You can describe a Knative service by using the kn service describe
command.
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:
--verbose
flagName: 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
--verbose
flagName: 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