Kubernetes port forwarding for local development.

NOTE: Accepting pull requests for bug fixes, tests, and documentation only.

kubefwd - kubernetes bulk port forwarding

kubefwd (Kube Forward)

Read Kubernetes Port Forwarding for Local Development for background and a detailed guide to kubefwd. Follow Craig Johnston on Twitter for project updates.

kubefwd is a command line utility built to port forward multiple services within one or more namespaces on one or more Kubernetes clusters. kubefwd uses the same port exposed by the service and forwards it from a loopback IP address on your local workstation. kubefwd temporarily adds domain entries to your /etc/hosts file with the service names it forwards.

Key Differentiator: Unlike kubectl port-forward, kubefwd assigns each service its own unique IP address (127.x.x.x), allowing multiple services to use the same port simultaneously without conflicts. This enables you to run multiple databases on port 3306 or multiple web services on port 80, just as they would in the cluster.

When working on our local workstation, my team and I often build applications that access services through their service names and ports within a Kubernetes namespace. kubefwd allows us to develop locally with services available as they would be in the cluster.

kubefwd - Kubernetes port forward

Quick Start

# macOS
brew install txn2/tap/kubefwd

# Linux (download from releases page)
# https://github.com/txn2/kubefwd/releases

# Windows
scoop install kubefwd

# Run kubefwd (requires sudo for /etc/hosts and network interface management)
sudo -E kubefwd svc -n <your-namespace>

Press Ctrl-C to stop forwarding and restore your hosts file.

Supported Platforms

macOS (tested on Intel and Apple Silicon)
Linux (tested on various distributions and Docker containers)
Windows (via Scoop package manager or Docker)

Installation

macOS Install / Update

kubefwd assumes you have kubectl installed and configured with access to a Kubernetes cluster. kubefwd uses the kubectl current context. The kubectl configuration is not used. However, its configuration is needed to access a Kubernetes cluster.

Ensure you have a context by running:

kubectl config current-context

If you are running MacOS and use homebrew you can install kubefwd directly from the txn2 tap:

brew install txn2/tap/kubefwd

To upgrade:

brew upgrade kubefwd

Linux Install / Update

Download pre-built binaries from the releases page:

.deb packages for Debian/Ubuntu
.rpm packages for RHEL/CentOS/Fedora
.tar.gz archives for any Linux distribution

Example for Debian/Ubuntu:

# Download the latest .deb file from releases page
sudo dpkg -i kubefwd_*.deb

Windows Install / Update

Using Scoop:

scoop install kubefwd

To upgrade:

scoop update kubefwd

Docker

Forward all services from the namespace the-project to a Docker container named the-project:

docker run -it --rm --privileged --name the-project \
    -v "$(echo $HOME)/.kube/":/root/.kube/ \
    txn2/kubefwd services -n the-project

Execute a curl call to an Elasticsearch service in your Kubernetes cluster:

docker exec the-project curl -s elasticsearch:9200

Key Features

Bulk Port Forwarding: Forward all services in a namespace with a single command
Unique IP per Service: Each service gets its own 127.x.x.x IP address, eliminating port conflicts
Automatic /etc/hosts Management: Service hostnames automatically added and removed
Headless Service Support: Forwards all pods for headless services
Dynamic Service Discovery: Automatically starts/stops forwarding as services are created/deleted
Pod Lifecycle Monitoring: Detects pod changes and maintains forwarding
Label & Field Selectors: Filter which services to forward
Multiple Namespace Support: Forward services from multiple namespaces simultaneously
Port Mapping: Remap service ports to different local ports
IP Reservation: Configure specific IP addresses for services

Contribute

Fork kubefwd and build a custom version.

Pull Request Policy: We are accepting pull requests for:

Bug fixes
Tests and test improvements
Stability and compatibility enhancements
Documentation improvements

Note: We are not accepting new feature requests at this time.

Usage

Important: kubefwd requires sudo (root access) to modify your /etc/hosts file and create network interfaces. Use sudo -E to preserve your environment variables, especially KUBECONFIG.

Basic Usage

Forward all services in a namespace:

sudo -E kubefwd svc -n the-project

Kubefwd finds the first Pod associated with each Kubernetes service in the namespace and port forwards it based on the Service spec to a local IP address and port. Service hostnames are added to your /etc/hosts file pointing to the local IP.

How it works:

Normal Services: Forwards the first available pod using the service name
Headless Services: Forwards all pods (first pod accessible via service name, others via pod-name.service-name)
Service Monitoring: Automatically starts/stops forwarding when services are created/deleted
Pod Monitoring: Automatically restarts forwarding when pods are deleted or rescheduled

Advanced Usage

Filter services with label selectors:

sudo -E kubefwd svc -n the-project -l system=wx

Forward a single service using field selector:

sudo -E kubefwd svc -n the-project -f metadata.name=my-service

Forward multiple services using the in clause:

sudo -E kubefwd svc -n the-project -l "app in (app1, app2)"

Forward services from multiple namespaces:

sudo -E kubefwd svc -n default -n the-project -n another-namespace

Forward all services from all namespaces:

sudo -E kubefwd svc --all-namespaces

Use custom domain suffix:

sudo -E kubefwd svc -n the-project -d internal.example.com

Port mapping (map service port to different local port):

sudo -E kubefwd svc -n the-project -m 80:8080 -m 443:1443

Use IP reservation configuration:

sudo -E kubefwd svc -n the-project -z path/to/conf.yml

Reserve specific IP for a service:

sudo -E kubefwd svc -n the-project -r my-service.the-project:127.3.3.1

Enable verbose logging for debugging:

sudo -E kubefwd svc -n the-project -v

Help

$ kubefwd svc --help

INFO[00:00:48]  _          _           __             _     
INFO[00:00:48] | | ___   _| |__   ___ / _|_      ____| |    
INFO[00:00:48] | |/ / | | | '_ \ / _ \ |_\ \ /\ / / _  |    
INFO[00:00:48] |   <| |_| | |_) |  __/  _|\ V  V / (_| |    
INFO[00:00:48] |_|\_\\__,_|_.__/ \___|_|   \_/\_/ \__,_|    
INFO[00:00:48]                                              
INFO[00:00:48] Version 0.0.0                                
INFO[00:00:48] https://github.com/txn2/kubefwd              
INFO[00:00:48]                                              
Forward multiple Kubernetes services from one or more namespaces. Filter services with selector.

Usage:
  kubefwd services [flags]

Aliases:
  services, svcs, svc

Examples:
  kubefwd svc -n the-project
  kubefwd svc -n the-project -l app=wx,component=api
  kubefwd svc -n default -l "app in (ws, api)"
  kubefwd svc -n default -n the-project
  kubefwd svc -n default -d internal.example.com
  kubefwd svc -n the-project -x prod-cluster
  kubefwd svc -n the-project -m 80:8080 -m 443:1443
  kubefwd svc -n the-project -z path/to/conf.yml
  kubefwd svc -n the-project -r svc.ns:127.3.3.1
  kubefwd svc --all-namespaces

Flags:
  -A, --all-namespaces          Enable --all-namespaces option like kubectl.
  -x, --context strings         specify a context to override the current context
  -d, --domain string           Append a pseudo domain name to generated host names.
  -f, --field-selector string   Field selector to filter on; supports '=', '==', and '!=' (e.g. -f metadata.name=service-name).
  -z, --fwd-conf string         Define an IP reservation configuration
  -h, --help                    help for services
  -c, --kubeconfig string       absolute path to a kubectl config file
  -m, --mapping strings         Specify a port mapping. Specify multiple mapping by duplicating this argument.
  -n, --namespace strings       Specify a namespace. Specify multiple namespaces by duplicating this argument.
  -r, --reserve strings         Specify an IP reservation. Specify multiple reservations by duplicating this argument.
  -l, --selector string         Selector (label query) to filter on; supports '=', '==', and '!=' (e.g. -l key1=value1,key2=value2).
  -v, --verbose                 Verbose output.

Troubleshooting

Permission Errors

Always use sudo -E to run kubefwd. The -E flag preserves your environment variables, especially KUBECONFIG:

sudo -E kubefwd svc -n the-project

Connection Refused Errors

If you see errors like connection refused or localhost:8080, ensure:

kubectl is properly configured
You can connect to your cluster: kubectl get nodes
Your KUBECONFIG is preserved with the -E flag

Stale /etc/hosts Entries

If kubefwd exits unexpectedly, your /etc/hosts file might contain stale entries. kubefwd backs up your original hosts file to ~/hosts.original. You can restore it:

sudo cp ~/hosts.original /etc/hosts

Services Not Appearing

Check that:

Services have pod selectors (services without selectors are not supported)
Pods are in Running or Pending state
You have RBAC permissions to list/get/watch pods and services
Use verbose mode (-v) to see detailed logs

Port Conflicts

If you encounter port conflicts, use IP reservations to assign specific IPs to services:

sudo -E kubefwd svc -n the-project -r service1:127.2.2.1 -r service2:127.2.2.2

Or create a configuration file (see example.fwdconf.yml).

Known Limitations

UDP Protocol: Not supported due to Kubernetes API limitations
Services Without Selectors: Services backed by manually created Endpoints are not supported
Manual Pod Restart Required: If pods restart due to deployments or crashes, you may need to restart kubefwd

Getting Help

Documentation: See CLAUDE.md for detailed architecture and development guide
Issues: Report bugs or issues on GitHub Issues
Blog Post: Read the detailed guide at Kubernetes Port Forwarding for Local Development

License

Apache License 2.0

Open source utility by Craig Johnston, imti blog and sponsored by Deasil Works, Inc.

Please check out my book Advanced Platform Development with Kubernetes: Enabling Data Management, the Internet of Things, Blockchain, and Machine Learning.

Source code from the book Advanced Platform Development with Kubernetes: Enabling Data Management, the Internet of Things, Blockchain, and Machine Learning by Craig Johnston (@cjimti) ISBN 978-1-4842-5610-7 Apress; 1st ed. edition (September, 2020)

Read my blog post Advanced Platform Development with Kubernetes for more info and background on the book.

Follow me on Twitter: @cjimti (Craig Johnston)