#k8-2 Node.js in Kubernetes: Define a Single-Container Pod with ConfigMap Environment Variables

Node.js Pod with ConfigMap Environment Variables

Scenario

🔒 Role: DevOps Engineer / Kubernetes Admin

⭐ Task:
1️⃣ You have a Node.js app
2️⃣ It needs to run as a single-container Pod
3️⃣ The container name should be app
4️⃣ Use the official Node.js image, version 18
5️⃣ Inject environment variables stored in a ConfigMap named node-environment-config using envFrom

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Video Explanation:

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1️⃣ Let's say the container name is app. It uses the official Node.js image. For example, we take version 18.

containers:
  - name: app
    image: node:18

2️⃣ Now, since our application needs environment variables and those variables are stored in a config map called node-env-config, so we can inject them directly into the container using an env from field. And we refer to the config map by its name, node-env-config, using config map reference.

envFrom:
  - configMapRef:
      name: node-env-config 

3️⃣ Full YAML

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Full playlist: Module 2 - Kubernetes Real World YAML Creation

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Here’s the flow Step by Step based on YAML:

• Kubernetes reads the YAML – It sees a Pod definition named node-app-pod.

• Pod created – Kubernetes schedules it on an available node in the cluster.

• Container pulled – From the node:18 image (Docker Hub).

• Container runs – Inside the Pod as app.

• Environment variables loaded – From the node-env-config ConfigMap, so PORT, NODE_ENV, etc., are available inside the container.

• You apply it – kubectl apply -f node-app-pod.yaml.

• You verify it – kubectl get pods to ensure the Pod is in Running state.

• You access it – kubectl exec -it node-app-pod -- bash to go inside, or later expose it via a Service for external access.

📺 Watch full explanation here:

• “10 Kubernetes YAML Real-World Questions” video:

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