Deploy a sample Node.js application on Kubernetes

For the exercise you will have access to a Red Hat OpenShift cluster. You can use the Kubernetes documentation if you want, and use the kubectl commands. Or if you prefer, you can use the Red Hat OpenShift documentation and use the oc commands.

If you already know the commands but don’t remember the options, you can use the --help after the command to get help, or -h for short. For example:

kubectl create deployment --help 
kubectl create deployment -h

This exercise also requires git on your terminal, see Install git

1. The application is available on https://github.com/ericbos111/nodejs-sample

   It uses port 3001.

2. Install the OpenShift cli from the OpenShift web interface > Help (the question mark)

   or from mirror.openshift.com, choose the same version as the cluster version. What I usually do is copy the link, and then from my terminal window, fetch this link with curl:

curl -lO https://mirror.openshift.com/pub/openshift-v4/clients/ocp/4.18.9/openshift-client-linux-amd64-rhel9-4.18.9.tar.gz

Decompress the file with tar xvf

tar xvf https://mirror.openshift.com/pub/openshift-v4/clients/ocp/4.18.9/openshift-client-linux-amd64-rhel9-4.18.9.tar.gz

Copy the files to your path

cp oc kubectl /usr/local/bin/

3. Login to the cluster, you can copy the login command from the web interface, or use something like this

oc login api.<instance>.techzone.ibm.com:6443 -u kubeadmin -p <password>

4. Create your own namespace or project, using the official documentation.

oc new-project eric

5. Deploy this application to your namespace in any way you like.

oc new-app https://github.com/ericbos111/nodejs-sample

6. Create a Service and an Ingress or a Route, using the official documentation.

oc create route edge --service=nodejs-sample --port=3001

Get the Ingress or Route, using the official documentation.

oc get route

Verify if you can access the route, either from your browser or with curl

curl -k https://<route>

If you are getting errors, you might want to edit your service to make sure that it uses port 3001 as the target port

7. Now, if you want to challenge yourself, you can fork the repo to your own Github, edit the application (in your own repository) and restart the build, for example, change the text “Hello from Node.js Starter Application!” to something else. Observe what happens. After some time, the result of your curl command will have changed.

Relationship between 'devfile' and 'Dockerfile'

Before you begin creating an application with this devfile code sample, it's helpful to understand the relationship between the devfile and Dockerfile and how they contribute to your build. You can find these files at the following URLs:

• Node.js devfile.yaml
• Node.js Dockerfile

1. The devfile.yaml file has an image-build component that points to your Dockerfile.
2. The Dockerfile contains the instructions you need to build the code sample as a container image.
3. The devfile.yaml kubernetes-deploy component points to a deploy.yaml file that contains instructions for deploying the built container image.
4. The devfile.yaml deploy command completes the outerloop deployment phase by pointing to the image-build and kubernetes-deploy components to create your application.

License

This stack is licensed under the EPL 2.0 license.

Additional resources

• For more information about Node.js, see How do I start with Node.js after I installed it?.
• For more information about devfiles, see Devfile.io.
• For more information about Dockerfiles, see Dockerfile reference.