Kubernetes ConfigMap Explained: API Resource, YAML Example, and Use Cases

Content of reverseproxy.conf

---------------------------
server {
    listen       80;
    server_name  localhost;

    location / {
        proxy_bind 127.0.0.1;
        proxy_pass http://127.0.0.1:3000;
    }

    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }
}Code language: PHP (php)

Commands to execute to create configmap

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kubectl create configmap my-config --from-file=reverseproxy.conf
kubectl get cm
kubectl describe cm my-configCode language: JavaScript (javascript)

Example pod using configmap

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apiVersion: v1
kind: Pod
metadata:
  name: helloworld-nginx
  labels:
    app: helloworld-nginx
spec:
  containers:
  - name: nginx
    image: nginx:1.11
    ports:
    - containerPort: 80
    volumeMounts:
    - name: config-volume
      mountPath: /etc/nginx/conf.d
  - name: k8s-demo
    image: wardviaene/k8s-demo
    ports:
    - containerPort: 3000
  volumes:
    - name: config-volume
      configMap:
        name: my-config
        items:
        - key: reverseproxy.conf
          path: myconfo.confCode language: JavaScript (javascript)

Validating configmap inside a pod

---------------------------
kubectl exec -it helloworld-nginx /bin/bash
cd /etc/nginx/conf.d

Rajesh Kumar

I’m Rajesh Kumar, a DevOps, SRE, DevSecOps, Cloud, and Platform Engineering expert passionate about sharing practical knowledge, real-world experiences, and industry best practices. I have worked at Cotocus and regularly write about technology, travel, investing, health, product reviews, and digital marketing through my various platforms.

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