K8S Hands-On Lab

This Lab deploys a sinatra application to a K8S cluster in the cloud.

Getting started

• Running the Sinatra App locally
• Running the Sinatra App in a local container
• Setting up Kubectl to connect to the cluster
• Deploy the Sinatra App image to a Kubernetes Cluster

Running the Sinatra App locally

Before you start, make sure you are using ruby version 3.1. You can check the version by running ruby -v.

1. Clone this repository:

    git clone git@github.com:HeitorMC/HandsOn-k8s.git

2. Change into the application directory:

    cd HandsOn-k8s

3. install the dependencies:

    bundle exec ruby app.rb

4. Run the app

    bundle exec ruby app.rb

5. The web application will be availabe at http://localhost:4567/

Running the Sinatra App in a local container

1. Clone this repository:

    git clone git@github.com:HeitorMC/HandsOn-k8s.git

2. Change into the application directory:

    cd HandsOn-k8s

3. Build the app’s container image

    docker build -t sinatra-app .

4. Run the container

    docker run -p 4567:4567 sinatra-app

5. The web application will be availabe at http://localhost:4567/

Setting up Kubectl to connect to the cluster

1. Download the latest release of kubectl with the command:

   curl -LO https://storage.googleapis.com/kubernetes-release/release/$(curl -s https://storage.googleapis.com/kubernetes-release/release/stable.txt)/bin/linux/amd64/kubectl

2. Install kubectl using the following command:

   chmod +x ./kubectl
   sudo mv ./kubectl /usr/local/bin/kubectl

3. Verify that kubectl is installed correctly by running the following command:

   kubectl version --client

4. Import your kubeconfig file and after that you can connect to the cluster using the following command:

   export KUBECONFIG=kubeconfig.yaml

Deploy the Sinatra App image to a Kubernetes Cluster

1. Assuming your image is already available in the docker hub, you can run the following command to deploy the image to the cluster:

   kubectl run <pod-name> <image-name:tag> --port=4567

2. Run the following command to see the pods running in the cluster:

   kubectl get pods

   The pods will be running in the cluster. However, there is an better way to deploy the image to the cluster pod.

3. We will use a K8S deployment to deploy the image to the cluster. Create a deployment file, you can use k8s-deployment.yaml.example as an example or check this link and build your own deployment file.

After creating the deployment file, run:

kubectl apply -f <your-deployment-file.yaml>

Now run the following command to see the pods running in the cluster:

kubectl get pods

For a more detailed view, run the following command:

kubectl get pods -o wide

4. Now we'll set a K8S Service to expose the pods. Create a service file, you can use k8s-service.yaml.example as an example or check this link and build your own service file.

After creating the service file, run:

kubectl apply -f <your-service-file.yaml>

And run the following command to see the service running in the cluster:

kubectl describe services

Finally, copy the external IP and paste it in your browser, you'll see the web application running in the cluster. 🎉🎉🎉