Migrating an Existing Service

This guide shows how to prepare a web service to run in a container on Knative serving. It does not cover data migration.

Identify the port your code is listening on

Your service should listen for requests on a specific port. You must identify this port and configure Knative serving to send request to the same port.

This is the same port you would use when invoking your service on your local machine. For example, if to test your code you open localhost:3000, then set the container port to 3000 in Knative serving.

Knative serving defaults to sending requests to 8080. The value of the port to which requests are sent is always available in the PORT environment variable. It is a best practice for your code to listen on the value defined by the PORT environment variable if possible.

Remove reliance on local filesystem for persistent storage

Check your application code for reliance on local filesystems, and replace it with file storage on Cloud Storage or data storage such as Firestore or Cloud SQL.

Add a Dockerfile

In order to wrap your service in a container, you should use a Dockerfile to define the operating environment. Read more about customizing your Dockerfile on the Developing your service page.

Tune for concurrency and memory limits

Learn about concurrency in Knative serving and how to optimize your services in development tips for tuning concurrency.

Make sure your memory limit is high enough for your application to run, including capacity for any temporary file storage your service requires.

Send logs to stdout or stderr

Knative serving automatically uses Google Cloud Observability to aggregate and review your logs, as described in the logging page.