Skip to main content
Intercept a Kubernetes pod using Telepresence, mount its ConfigMap volume on your local machine, and access configuration data as if the service were running in-cluster.

​
Table of Contents

​
Prerequisites

  • Kubernetes cluster access with kubectl configured
  • Telepresence installed
  • A local .env file for environment variables
Ensure your kubectl context is pointing to the intended cluster before starting the intercept.

​
Node.js Service Example

The products service is an Express.js app that reads API_URL from environment variables: 
require('dotenv').config({ override: true });
const express = require("express");
const app = express();
const port = 8000;

const apiURL = process.env.API_URL;
console.log("API_URL:", apiURL);

const products = [
  {
    id: 1,
    name: "iPhone 14",
    price: 900,
    category: "electronics",
    onSale: false,
  },
];

app.get("/products", (req, res) => {
  res.json(products);
});

app.listen(port, () => {
  console.log(`Products service listening on port ${port}`);
});

​
Kubernetes Deployment with ConfigMap Volume

Deploy the products-depl Deployment and mount a ConfigMap called db-info at /tmp: 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: products-depl
spec:
  selector:
    matchLabels:
      app: products
  template:
    metadata:
      labels:
        app: products
    spec:
      volumes:
        - name: db-config
          configMap:
            name: db-info
      containers:
        - name: products
          image: sanjeevkt720/telepresence-products
          imagePullPolicy: Always
          ports:
            - containerPort: 8000
              name: web
          volumeMounts:
            - name: db-config
              mountPath: /tmp
          env:
            - name: API_URL
              value: "http://api.example.com"

​
ConfigMap Definition

Define your database connection details in a ConfigMap: 
apiVersion: v1
kind: ConfigMap
metadata:
  name: db-info
data:
  DB_HOST: "prod.db"
  DB_USERNAME: "myusername123"
  DB_PASSWORD: "mypassword123"
KeyValue
DB_HOSTprod.db
DB_USERNAMEmyusername123
DB_PASSWORDmypassword123

​
Intercepting with Telepresence and Mounting Volumes

  1. Check for existing intercepts: 
    telepresence list
  2. Create an intercept on port 8000, inject your .env, and mount the pod’s volumes: 
    telepresence intercept products-depl \
  --port 8000 \
  --env-file .env \
  --mount
Redirecting service traffic through your local machine may impact production workloads. Proceed with caution.
Example output (identifiers will vary): 
Using Deployment products-depl
  Intercept name          : products-depl
  State                   : ACTIVE
  Workload kind           : Deployment
  Destination             : 127.0.0.1:8000
  Service Port Identifier : 8000/TCP
  Volume Mount Point      : /tmp/telfs-2391723209
  Intercepting            : all TCP connections

​
Exploring the Mounted Volume

In a new terminal: 
cd /tmp/telfs-2391723209/tmp
ls
cat DB_HOST
# prod.db
You now have file-based access to the ConfigMap data.

​
Customizing the Local Mount Path

  1. End the current intercept: 
    telepresence leave products-depl
  2. Start a new intercept with a custom mount location: 
    telepresence intercept products-depl \
  --port 8000 \
  --env-file .env \
  --mount=/tmp/example123
Files now appear under /tmp/example123/tmp: 
cd /tmp/example123/tmp
ls
# DB_HOST  DB_PASSWORD  DB_USERNAME
Adjust your application or use symbolic links to consume these local files seamlessly.

​
References

Watch Video