Deploy & Configure·Last Verified: 2026-07-14

Container Ports & $PORT

Bind your application web server to the correct port to serve traffic.

A common reason deployments fail on Kubeletto is port binding mismatches. Your application container must listen on the port Knative expects.

How Kubeletto Routes Traffic

Kubeletto routes external HTTPS traffic to your container on the configured container port (default: 8080). At runtime, Knative automatically injects the PORT environment variable corresponding to this configuration.

Your application MUST listen on address 0.0.0.0 (all interfaces) and the port provided by the $PORT environment variable. Binding to localhost (127.0.0.1) or hardcoding 3000/5000 will cause routing checks to fail with a PORT_MISMATCH error.

Port Configuration Example (CLI)

If your application is configured to listen on port 3000, specify that during deployment:

Deploy on Port 3000
kubeletto deploy my-service --image node-app:latest --port 3000
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