This is an incredibly useful tool. If you have an application running in Kubernetes and you need to connect to you application or database, you can simply forward a port to your local machine via the kubectl port-forward command.
Let's say you have a MySQL database running in Kubernetes and you don't want to expose it outside of your cluster, but you need to connect a client to the database to run commands against the database. Here's what you'd do...
- Determine the name of your database pod or the service that exposes it. (Preferably the master pod in a Stateful Set)
- Run the command
kubectl port-forward pods/<pod name> <local port>:<pod port>(or replace "pod" with "service") - Connect to your application with
localhost:<local port>or127.0.0.1:<local port>
That's it! At this point, you should be able to connect your database client to the pod with step 3 and run the commands that you need. This same method applies to applications. Now you could browse to http://localhost:<local port>/api/... to hit the endpoints of an HTTP REST API that you might have forwarded.
Happy Kuberneting!