🌟 Cosmocloud: Unified Application Deployment with Helm Chart

Welcome to the Cosmocloud Deploy Helm Chart! This Helm chart helps you deploy three essential components — Backend, Frontend, and Redis Database together in a Kubernetes cluster. Below, you'll find detailed instructions, explanations for each file, and a walkthrough of the deployment process.

📄 Chart Structure

The cosmocloud-deploy chart is structured as follows:

cosmocloud-deploy/
├── templates/               # Contains all Kubernetes manifests
│   ├── backend-deployment.yaml
│   ├── backend-service.yaml
│   ├── frontend-deployment.yaml
│   ├── frontend-service.yaml
│   ├── redis-deployment.yaml
│   ├── redis-service.yaml
│   ├── configmap.yaml
│   └── NOTES.txt         
├── Chart.yaml               # Metadata about this Helm chart
├── values.yaml              # Default configuration values

📝 Files Explained

1. 📜 Chart.yaml

This file defines metadata about the Helm chart. Here’s a breakdown of its key fields:

• apiVersion: Specifies the Helm chart API version (v2 for Helm 3).

• name: Name of the chart (cosmocloud-deploy).

• description: Brief summary of the chart.

• version: Version of the Helm chart.

• appVersion: Version of the application(s) being deployed.

  Purpose: Helps Helm understand and manage the chart versioning.

2. 🎛️ values.yaml

This file contains default configurations for the chart. It allows you to:

• Customize settings like image names, ports, and replicas.
• Define ConfigMap values for environment variables.

Key Configurations:

replicaCount: 1                          # Number of replicas for each Deployment
backend:                                 # Backend configuration
  image:
    repository: shreybatra/sample-backend
    pullPolicy: IfNotPresent            # Image pull policy when container runtime pulling image from registry
  service:
    type: ClusterIP
    port: 8000

frontend:                               # Frontend configuration
  image:
    repository: shreybatra/sample-frontend
    pullPolicy: IfNotPresent
  service:
    type: NodePort                     # using NodePort as service type to expose it to user in order to access the application
    port: 5173
    nodePort: 31000

redis:                                 # Redis configuration
  image:
    repository: redis
    pullPolicy: IfNotPresent
  service:
    type: ClusterIP
    port: 6379

Purpose: Simplifies customization without modifying templates directly.

3. 🗂️ templates/configmap.yaml

Defines a ConfigMap used to pass environment variables to the applications. It references values from values.yaml.

Key Snippet:

apiVersion: v1
kind: ConfigMap
metadata:
  name: app-env-configmap
  namespace: default
data:
  REDIS_URI: redis://redis-svc:6379
  BACKEND_URL: http://backend-svc:8000

Purpose: Centralized Configuration Management The ConfigMap holds environment-specific details (REDIS_URI and BACKEND_URL) that are critical for the application's operation. By defining them in a ConfigMap:

• Configurations are decoupled from the application code.
• It becomes easier to manage and update configurations without modifying the application or its container image.

Key-Value Pairs in data:

REDIS_URI: Points to the Redis service (redis-svc) running within the cluster on the default port 6379.

• Enables the backend to connect to Redis for caching, session storage, or other database like tasks.

BACKEND_URL: Points to the backend service (backend-svc) running within the cluster on port 8000.

• Enables the frontend to send API requests to the backend.

---

4. ⚙️ templates/backend-deployment.yaml

Creates the Backend Deployment with:

👉 Container image: shreybatra/sample-backend.

👉 Environment variables: REDIS_URI from the ConfigMap.

👉 Port: Exposes the container on port 8000.

env:
    - name: REDIS_URI
      valueFrom:
         configMapKeyRef:
            name: app-env-configmap
            key: REDIS_URI

Purpose: Ensures the backend can connect to Redis using the environment variable.

5. 🌐 templates/backend-service.yaml

Exposes the Backend as a ClusterIP service:

• Service name: backend-svc.
• Port: 8000. Key Snippet:

spec:
  type: ClusterIP
  selector:              # using selector `app: backend` to connect the svc with the specific backend pod
    app: backend
  ports:
    - protocol: TCP
      port: {{ .Values.backend.service.port }}

Purpose: Provides internal networking for the backend service.

6. ⚙️ templates/frontend-deployment.yaml

Creates the Frontend Deployment with:

• Container image: shreybatra/sample-frontend.
• Environment variables: BACKEND_URL from the ConfigMap.
• Port: Exposes the container on port 5175.

Key Snippet:

env:
    - name: BACKEND_URL
      valueFrom:
          configMapKeyRef:
              name: app-env-configmap
              key: BACKEND_URL

Purpose: Connects the frontend to the backend service.

7. 🌐 templates/frontend-service.yaml

Exposes the Frontend as a NodePort service:

• Service name: frontend-svc.
• Port: 5175.
• NodePort: 31000. Key Snippet:

spec:
  type: NodePort
  selector:
    app: frontend
  ports:
    - protocol: TCP
      port: {{ .Values.frontend.service.port }}
      nodePort: {{ .Values.frontend.service.nodePort }}

Purpose: Makes the frontend accessible from outside the cluster as using svc type NodePort.

8. ⚙️ templates/redis-deployment.yaml

Creates the Redis Deployment with:

• Container image: redis.
• Port: Exposes the container on port 6379. Purpose: Deploys the Redis database for backend data storage.

9. 🌐 templates/redis-service.yaml

Exposes Redis as a ClusterIP service:

• Service name: redis-svc.
• Port: 6379. Purpose: Enables backend to connect to Redis internally.

---

🚀 How to Use

1. Install Helm

Ensure Helm is installed on your system:

helm version

2. Package the Chart

helm package cosmocloud-deploy

3. Deploy the Chart

Install the chart into your Kubernetes cluster:

helm install cosmocloud cosmocloud-deploy

OUTPUT:

NAME: cosmocloud
LAST DEPLOYED: Mon Dec  2 20:09:19 2024
NAMESPACE: default
STATUS: deployed
REVISION: 1
TEST SUITE: None
NOTES:
Thank you for installing cosmocloud-deploy.

Your release is named cosmocloud.

To learn more about the release, try:

  $ helm status cosmocloud
  $ helm get all cosmocloud

4. Verify Resources

Check if all resources were deployed successfully:

kubectl get all -n default

5. Access Services

• Frontend: Use the NodePort (e.g., http://<NodeIP>:31000 or localhost:31000 NOTE:- [use port forwarding to access the nodeport on localhost]). Refer this post if you are using kind cluster for config.yaml Link

🛠️ Customization

Modify values.yaml to adjust configurations such as image versions, ports, and environment variables.

📚 Troubleshooting

• Error: ImagePullBackOff
  • Ensure the specified images are accessible from your cluster.
• Error: CrashLoopBackOff
  • Check logs with kubectl logs <pod-name>.

🎉 Congratulations!

You’ve successfully deployed your Cosmocloud applications using a Helm chart! Happy Helm-ing! 🚀