Migrate droplet to kubernetes

Hey,

Migrating your application from a Droplet to a Kubernetes cluster is a good move to take advantage of the autoscaling and manage your resources efficiently.

There are a few things that you should keep in mind before starting:

1. Understanding Kubernetes Concepts: It’s crucial to grasp core Kubernetes concepts such as Pods, Deployments, Services, and Namespaces. These are fundamental to orchestrating your application in a Kubernetes environment. Here is a free eBook by DigitalOcean to get you started with Kubernetes:

https://www.digitalocean.com/community/books/digitalocean-ebook-kubernetes-for-full-stack-developers

2. Setting Up a Kubernetes Cluster:

   • Create a Kubernetes cluster in DigitalOcean: You can do this via the DigitalOcean Control Panel or by using the doctl command-line tool.

     doctl kubernetes cluster create my-k8s-cluster --region nyc1 --size s-1vcpu-2gb --count 3
     

   • This command creates a cluster named my-k8s-cluster in the nyc1 region with 3 nodes of size s-1vcpu-2gb.

3. Containerizing Your Application:

   • Dockerize your application by creating a Dockerfile. Here’s a basic example for a Node.js app:

     FROM node:20
     WORKDIR /usr/src/app
     COPY package*.json ./
     RUN npm install
     COPY . .
     EXPOSE 3000
     CMD ["node", "app.js"]
     

   • Build your Docker image:

     docker build -t my-app:v1 .
     

     This is just an example, if you are using a different type of tech stack, you would need to create a different Dockerfile. Feel free to share more information about it and I can try helping out with the Dockerization.

4. Pushing Your Docker Image:

   • Tag and push the image to a container registry, such as Docker Hub or DigitalOcean Container Registry.

     docker tag my-app:v1 mydockerhubusername/my-app:v1
     docker push mydockerhubusername/my-app:v1
     

5. Creating Kubernetes Manifests:

   • Define a deployment YAML file (deployment.yaml) for your application:

     apiVersion: apps/v1
     kind: Deployment
     metadata:
       name: my-app-deployment
     spec:
       replicas: 3
       selector:
         matchLabels:
           app: my-app
       template:
         metadata:
           labels:
             app: my-app
         spec:
           containers:
           - name: my-app
             image: mydockerhubusername/my-app:v1
             ports:
             - containerPort: 3000
     

   • Define a service YAML file (service.yaml) to expose your application:

     apiVersion: v1
     kind: Service
     metadata:
       name: my-app-service
     spec:
       type: LoadBalancer
       ports:
       - port: 80
         targetPort: 3000
       selector:
         app: my-app
     

     Here is a link to the documentation about this as well:

     https://docs.digitalocean.com/products/kubernetes/how-to/add-load-balancers/

6. Deploying Your Application:

   • Apply your Kubernetes manifests using kubectl:

     kubectl apply -f deployment.yaml
     kubectl apply -f service.yaml
     

7. Configuring Autoscaling:

   • Set up Horizontal Pod Autoscaler to enable autoscaling based on CPU usage:

     kubectl autoscale deployment my-app-deployment --cpu-percent=50 --min=1 --max=10
     

   • This command autoscales the my-app-deployment based on CPU usage, maintaining a target of 50% CPU usage across all pods.

For more information on the autoscaling configuraiton you can take a look at the documentation here:

https://docs.digitalocean.com/products/kubernetes/how-to/autoscale/

Also make sure that your application functions correctly in the new Kubernetes environment. Test endpoints, data persistence, and performance.

Only once you’re confident in the Kubernetes deployment, update your DNS records to point to the LoadBalancer service IP.

If you encounter any hurdles or have more questions during your migration, feel free to ask. The community is here to support you!

Best,

Bobby