// Module is included in the following assemblies:
//
// serverless/knative_cli/knative-cli.adoc

[id="basic-workflow_{context}"]
= Basic workflow using `kn`

The following basic workflow deploys a simple `hello` service that reads the environment variable `RESPONSE` and prints its output.

You can use this guide as a reference to perform create, read, update, and delete (CRUD) operations on a service.

.Procedure

. Create a service in the `default` namespace from an image:
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[source,terminal]
----
$ kn service create hello --image docker.io/openshift/hello-openshift --env RESPONSE="Hello Serverless!"
----

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.Example output
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[source,terminal]
----
Creating service 'hello' in namespace 'default':

  0.085s The Route is still working to reflect the latest desired specification.
  0.101s Configuration "hello" is waiting for a Revision to become ready.
 11.590s ...
 11.650s Ingress has not yet been reconciled.
 11.726s Ready to serve.

Service 'hello' created with latest revision 'hello-gsdks-1' and URL:
http://hello-default.apps-crc.testing
----

. List the service:
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[source,terminal]
----
$ kn service list
----

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.Example output
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[source,terminal]
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NAME    URL                                     LATEST          AGE     CONDITIONS   READY   REASON
hello   http://hello-default.apps-crc.testing   hello-gsdks-1   8m35s   3 OK / 3     True
----

. Check if the service is working by using the `curl` service endpoint command:
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[source,terminal]
----
$ curl http://hello-default.apps-crc.testing
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.Example output
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[source,terminal]
----
Hello Serverless!
----

. Update the service:
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[source,terminal]
----
$ kn service update hello --env RESPONSE="Hello OpenShift!"
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.Example output
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[source,terminal]
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Updating Service 'hello' in namespace 'default':

 10.136s Traffic is not yet migrated to the latest revision.
 10.175s Ingress has not yet been reconciled.
 10.348s Ready to serve.

Service 'hello' updated with latest revision 'hello-dghll-2' and URL:
http://hello-default.apps-crc.testing
----
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The service's environment variable `RESPONSE` is now set to "Hello OpenShift!".

. Describe the service.
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[source,terminal]
----
$ kn service describe hello
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.Example output
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[source,terminal]
----
Name:       hello
Namespace:  default
Age:        13m
URL:        http://hello-default.apps-crc.testing

Revisions:
  100%  @latest (hello-dghll-2) [2] (1m)
        Image:  docker.io/openshift/hello-openshift (pinned to 5ea96b)

Conditions:
  OK TYPE                   AGE REASON
  ++ Ready                   1m
  ++ ConfigurationsReady     1m
  ++ RoutesReady             1m
----

. Delete the service:
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[source,terminal]
----
$ kn service delete hello
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.Example output
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[source,terminal]
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Service 'hello' successfully deleted in namespace 'default'.
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. Verify that the `hello` service is deleted by attempting to `list` it:
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[source,terminal]
----
$ kn service list hello
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.Example output
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[source,terminal]
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No services found.
----