Port forwarding
Port forwarding is a networking technique that redirects traffic from a port on one endpoint to a port or service on another endpoint.
Bootstrapping Microservices, Second Edition: With Docker, Kubernetes, GitHub Actions, and Terraform
Port forwarding is the redirection of network traffic arriving at one port to a designated port on another network endpoint.
- How it is used
- Provides local access to containerized microservices and temporary access to internal Kubernetes microservices for testing and diagnosis.
- How deep it goes
- Shows Docker and kubectl commands, port mappings, and basic verification; does not explain network-routing internals.
- Examples
- Uses a video-streaming container mapped from port 3000 to 3000 and a metadata pod forwarded from local port 6000 to port 80.
- What you can do after
- Operate/configure it with Docker or kubectl to reach a listening microservice and check its responses locally.
Kubernetes for Developers
Port forwarding maps a network port on one endpoint to a port on another endpoint so traffic can reach a service.
- How it is used
- Connects local development clients to container or Kubernetes services for testing and debugging.
- How deep it goes
- Explains host-to-service and host-to-container mappings with commands, access patterns, and a network-interface flag.
- Examples
- Uses a Python HTTP server, timeserver Kubernetes Service, localhost:8080, Redis on port 6379, and curl verification.
- What you can do after
- Apply it via kubectl or Docker to test services locally and connect external Docker containers to forwarded Kubernetes services.
Read how Kubernetes for Developers explains port forwarding →
Road to Kubernetes
Port forwarding is a networking technique that maps a local port to a port on a remote resource.
- How it is used
- Provides temporary local access for verifying a PostgreSQL database running in a Kubernetes cluster.
- How deep it goes
- Explains Pod, StatefulSet, and Service commands with port mappings, but stops short of in-cluster communication.
- Examples
- Uses postgres-0, a postgres StatefulSet, a postgres Service, port 3312, port 5432, and the psql client.
- What you can do after
- Operate/configure kubectl port forwarding and verify database access with a local PostgreSQL client.
ScyllaDB in Action
Port forwarding maps a port on one network endpoint to a port on another endpoint so that connections can reach a service.
- How it is used
- Enables a local application to reach a CQL service running inside a Docker container.
- How deep it goes
- Defines host-to-container mapping and applies it to Docker, but defers complicated multi-node workarounds.
- Examples
- Uses ScyllaDB 5.4 containers with mappings such as 9241:9042 and 9042:9042.
- What you can do after
- Operate/configure Docker port mappings so a local application can reach ScyllaDB during development.
Google Anthos in Action
Port forwarding is a networking technique that maps a port on one system to a port on another service or system.
- How it is used
- Enables local previews of services running in minikube or remote Kubernetes clusters.
- How deep it goes
- Shows the service-level kubectl command and local result, then places forwarding within Skaffold’s development pipeline.
- Examples
- Uses the hello-minikube Deployment, NodePort service, port 8080, and browser access at localhost.
- What you can do after
- Apply it via kubectl or Skaffold to preview a Kubernetes service from a local browser.
Related concepts
- kubectlused by · kubectl is the Kubernetes command-line client for communicating with the Kubernetes API and managing cluster resources.
- Dockerused by · Docker is a platform and ecosystem for building, distributing, and running applications in containers.
- servicecontrasts with · A Kubernetes Service is an API resource that provides stable network access and service discovery for a changing set of Pods or other specified destinations.
- docker runconfigured by · docker run is a Docker command that creates and starts a container from an image, with optional runtime configuration.
- Skaffoldconfigured by · Skaffold is a command-line tool that automates development workflows for building, deploying, and iterating on containerized applications.
- database drivercontrasts with · A database driver is client software that implements the interface or protocol an application uses to connect to and communicate with a database system.
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