Deploy a simple app using the OpenShift CLI

That blog post is a simple cheat sheet, how to deploy a containerized application to OpenShift. We using an existing container image on a public Quay Repository and the OpenShift CLI. This blog post is also a combination of existing blog posts to compare the automated created specifications to the predefined specifications in the blog post Configure a project in an IBM Cloud Red Hat OpenShift cluster to access the IBM Cloud Container Registry and use the login written in the blog post Log in to the an IBM Cloud Red Hat OpenShift cluster using the IBM Cloud and OpenShift CLI.

Step 1: Log on to the IBM Cloud Red Hat OpenShift cluster using the IBM Cloud CLI

To log on, just follow the steps in this blog post “Log in to the an IBM Cloud Red Hat OpenShift cluster using the IBM Cloud and OpenShift CLI¶

Step 2: Create a new project

oc new-project vend-simple

Step 3: Create a new deployment based on an existing image

The example is based on this source code: GitHub project.

oc new-app --docker-image quay.io/tsuedbroecker/vend-simple:v1

Step 4: Inspect the automated created deployment

  • Get newly created deployments
oc get deployments

Example output:

NAME          READY   UP-TO-DATE   AVAILABLE   AGE
vend-simple   1/1     1            1           17s

  • Inspect the automated created deployment specification
oc describe deployment vend-simple

Example output:

Name:                   vend-simple
Namespace:              vend-simple
CreationTimestamp:      Tue, 16 Nov 2021 18:43:52 +0100
Labels:                 app=vend-simple
                        app.kubernetes.io/component=vend-simple
                        app.kubernetes.io/instance=vend-simple
Annotations:            deployment.kubernetes.io/revision: 2
                        image.openshift.io/triggers:
                          [{"from":{"kind":"ImageStreamTag","name":"vend-simple:v1"},"fieldPath":"spec.template.spec.containers[?(@.name==\"vend-simple\")].image"}]
                        openshift.io/generated-by: OpenShiftNewApp
Selector:               deployment=vend-simple
Replicas:               1 desired | 1 updated | 1 total | 1 available | 0 unavailable
StrategyType:           RollingUpdate
MinReadySeconds:        0
RollingUpdateStrategy:  25% max unavailable, 25% max surge
Pod Template:
  Labels:       deployment=vend-simple
  Annotations:  openshift.io/generated-by: OpenShiftNewApp
  Containers:
   vend-simple:
    Image:        quay.io/tsuedbroecker/vend-simple@sha256:2e6bf9cd6f2921168573bf0270b531acc7863e9d3efdc63337b2cd5ef1b2146a
    Port:         3000/TCP
    Host Port:    0/TCP
    Environment:  <none>
    Mounts:       <none>
  Volumes:        <none>
Conditions:
  Type           Status  Reason
  ----           ------  ------
  Available      True    MinimumReplicasAvailable
  Progressing    True    NewReplicaSetAvailable
OldReplicaSets:  <none>
NewReplicaSet:   vend-simple-5b7555b454 (1/1 replicas created)
Events:
  Type    Reason             Age   From                   Message
  ----    ------             ----  ----                   -------
  Normal  ScalingReplicaSet  67s   deployment-controller  Scaled up replica set vend-simple-6ccdfbc85b to 1
  Normal  ScalingReplicaSet  66s   deployment-controller  Scaled up replica set vend-simple-5b7555b454 to 1
  Normal  ScalingReplicaSet  52s   deployment-controller  Scaled down replica set vend-simple-6ccdfbc85b to 0

Step 5: Inspect the automated the services

  • Get newly created services
oc get services

Example output:

NAME          TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
vend-simple   ClusterIP   172.21.61.249   <none>        3000/TCP   2m51s

  • Inspect the automated created service specification
oc describe service vend-simple

Example output:

Name:              vend-simple
Namespace:         vend-simple
Labels:            app=vend-simple
                   app.kubernetes.io/component=vend-simple
                   app.kubernetes.io/instance=vend-simple
Annotations:       openshift.io/generated-by: OpenShiftNewApp
Selector:          deployment=vend-simple
Type:              ClusterIP
IP Families:       <none>
IP:                172.21.61.249
IPs:               172.21.61.249
Port:              3000-tcp  3000/TCP
TargetPort:        3000/TCP
Endpoints:         172.17.51.166:3000
Session Affinity:  None
Events:            <none>

Step 6: Expose the service to create a route

oc expose service/vend-simple

Steo 7: Get the route and open the URL in browser to verify the output

oc get route | grep "vend"

  • Example output in your browser
"{\"message\":\"vend test - \"}"

Steo 8: Get the route and open the route in browser to verify the output

oc get pods

  • Example output:
NAME                           READY   STATUS    RESTARTS   AGE
vend-simple-5b7555b454-f9jw4   1/1     Running   0          14m

Step 9: Access the running pod on it’s command line

oc exec vend-simple-5b7555b454-f9jw4 ls

  • Example output:
kubectl exec [POD] [COMMAND] is DEPRECATED and will be removed in a future version. Use kubectl exec [POD] -- [COMMAND] instead.
docker_entrypoint.sh
generate_env-config.sh
modules
node_modules
package-lock.json
package.json
server.js

Summary

As we have seen, the oc new-app command is an easy straight forward way to create/deploy an application to OpenShift.


I hope this was useful for you and let’s see what’s next?

Greetings,

Thomas

#ibmcloud, #openshift, #roks

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