Developing and debugging services locally

Kubernetes applications usually consist of multiple, separate services, each running in its own container. Developing and debugging these services on a remote Kubernetes cluster can be cumbersome, requiring you to get a shell on a running container and running your tools inside the remote shell.

telepresence is a tool to ease the process of developing and debugging services locally, while proxying the service to a remote Kubernetes cluster. Using telepresence allows you to use custom tools, such as a debugger and IDE, for a local service and provides the service full access to ConfigMap, secrets, and the services running on the remote cluster.

This document describes using telepresence to develop and debug services running on a remote cluster locally.

Before you begin

• Kubernetes cluster is installed
• kubectl is configured to communicate with the cluster
• Telepresence is installed

Getting a shell on a remote cluster

Open a terminal and run telepresence with no arguments to get a telepresence shell. This shell runs locally, giving you full access to your local filesystem.

The telepresence shell can be used in a variety of ways. For example, write a shell script on your laptop, and run it directly from the shell in real time. You can do this on a remote shell as well, but you might not be able to use your preferred code editor, and the script is deleted when the container is terminated.

Enter exit to quit and close the shell.

Developing or debugging an existing service

When developing an application on Kubernetes, you typically program or debug a single service. The service might require access to other services for testing and debugging. One option is to use the continuous deployment pipeline, but even the fastest deployment pipeline introduces a delay in the program or debug cycle.

Use the --swap-deployment option to swap an existing deployment with the Telepresence proxy. Swapping allows you to run a service locally and connect to the remote Kubernetes cluster. The services in the remote cluster can now access the locally running instance.

To run telepresence with --swap-deployment, enter:

telepresence --swap-deployment $DEPLOYMENT_NAME

where $DEPLOYMENT_NAME is the name of your existing deployment.

Running this command spawns a shell. In the shell, start your service. You can then make edits to the source code locally, save, and see the changes take effect immediately. You can also run your service in a debugger, or any other local development tool.

What's next

If you're interested in a hands-on tutorial, check out this tutorial that walks through locally developing the Guestbook application on Google Kubernetes Engine.

Telepresence has numerous proxying options, depending on your situation.

For further reading, visit the Telepresence website.