STUNner: A Kubernetes media gateway for WebRTC
Ever wondered how to deploy your WebRTC infrastructure into the
cloud? Frightened away by the
complexities of Kubernetes container networking, and the surprising ways in which it may interact
with your UDP/RTP media? Read through the endless stream of Stack
Overflow
questions
asking
how
to
scale
WebRTC services with Kubernetes, just to get (mostly) insufficient answers? Want to safely connect
your users behind a NAT, without relying on expensive third-party TURN
services?
Worry no more! STUNner allows you to deploy any WebRTC service into Kubernetes, smoothly
integrating it into the cloud-native ecosystem. STUNner exposes a
standards-compliant STUN/TURN gateway for clients to access your virtualized WebRTC infrastructure
running in Kubernetes, maintaining full browser compatibility and requiring minimal or no
modification to your existing WebRTC codebase. STUNner supports the Kubernetes Gateway
API so you can configure it in the familiar YAML-engineering
style via Kubernetes manifests.
Table of Contents
- Description
- Features
- Getting started
- Usage
- Documentation
- Milestones
Description
Currently WebRTC
lacks
a
virtualization
story: there
is no easy way to deploy a WebRTC media service into Kubernetes to benefit from the
resiliency,
scalability,
and high
availability
features we have come to expect from modern network services. Worse yet, the entire industry relies
on a handful of public STUN
servers and hosted TURN
services to connect clients behind a NAT/firewall,
which may create a useless dependency on externally operated services, introduce a performance
bottleneck, raise security concerns, and come with a non-trivial price tag.
The main goal of STUNner is to allow anyone to deploy their own WebRTC infrastructure into
Kubernetes, without relying on any external service other than the cloud-provider's standard hosted
Kubernetes offering. STUNner can act as a standalone STUN/TURN server that WebRTC clients and media
servers can use as a scalable NAT traversal facility (headless model), or it can act as a gateway
for ingesting WebRTC media traffic into the Kubernetes cluster by exposing a public-facing
STUN/TURN server that WebRTC clients can connect to (media-plane model). This makes it possible to
deploy WebRTC application servers and media servers into ordinary Kubernetes pods, taking advantage
of the full cloud native feature set to manage, scale, monitor and troubleshoot the WebRTC
infrastructure like any other Kubernetes workload.
Don't worry about the performance implications of processing all your media through a TURN server:
STUNner is written in Go so it is extremely fast, it is co-located with your
media server pool so you don't pay the round-trip time to a far-away public STUN/TURN server, and
STUNner can be easily scaled up if needed just like any other "normal" Kubernetes service.
Features
Kubernetes has been designed and optimized for the typical HTTP/TCP Web workload, which makes
streaming workloads, and especially UDP/RTP based WebRTC media, feel like a foreign citizen.
STUNner aims to change this state-of-the-art, by exposing a single public STUN/TURN server port for
ingesting all media traffic into a Kubernetes cluster in a controlled and standards-compliant
way.
-
Seamless integration with Kubernetes. STUNner can be deployed into any Kubernetes cluster,
even into restricted ones like GKE Autopilot, using a single command. Manage your HTTP/HTTPS
application servers with your favorite service mesh, and STUNner takes care
of all UDP/RTP media. STUNner implements the Kubernetes Gateway
API so you configure it in exactly the same way as
the
rest
of
your
workload through easy-to-use YAML
manifests.
-
Expose a WebRTC media server on a single external UDP port. Get rid of the Kubernetes
hacks, like privileged pods and
hostNetwork
/hostPort
services, typically recommended as a prerequisite to containerizing your
WebRTC media plane. Using STUNner a WebRTC deployment needs only two public-facing ports, one
HTTPS port for signaling and a single UDP port for all your media.
-
No reliance on external services for NAT traversal. Can't afford a hosted TURN
service for client-side NAT traversal? Can't get decent
audio/video quality because the third-party TURN service poses a bottleneck? STUNner can be
deployed into the same cluster as the rest of your WebRTC infrastructure, and any WebRTC client
can connect to it directly without the use of any external STUN/TURN service whatsoever, apart
from STUNner itself.
-
Scale your WebRTC infrastructure. Tired of manually provisioning your WebRTC media servers?
STUNner lets you deploy the entire WebRTC infrastructure into ordinary Kubernetes pods, thus
scaling the media plane is as easy as issuing a kubectl scale
command. Or
you can use the built in Kubernetes horizontal autoscaler to automatically resize your workload
based on demand.
-
Minimal client-side configuration. STUNner comes with a built-in authentication
service that can be used to generate time-windowed
per-user TURN credentials through a standards
compliant HTTP REST
API. Just set the generated ICE
configuration
in the PeerConnection
JavaScript
API and
your clients will readily start using your Kubernetes-based WebRTC service via STUNner.
-
Secure perimeter defense. No need to open thousands of UDP/TCP ports on your media server for
potentially malicious access; with STUNner all media is received through a single ingress port
that you can tightly monitor and control.
-
Simple code and extremely small size. Written in pure Go using the battle-tested
pion/webrtc framework, STUNner is just a couple of hundred
lines of fully open-source code. The server is extremely lightweight: the typical STUNner
container image size is only 15 Mbytes.
The main uses of STUNner are hosting a scalable STUN server
pool
in Kubernetes, as a public Kubernetes-based TURN
service,
or as a fully-fledged gateway
service
for ingesting and load-balancing clients' media connections across a pool of WebRTC media servers
hosted in ordinary Kubernetes pods.
Getting Started
With a minimal understanding of WebRTC and Kubernetes, deploying STUNner should take less than 5
minutes, in five simple steps.
Note that the default installation does not contain an application server and a media server:
STUNner is not a WebRTC service in itself, it is merely an enabler for you to deploy your own
WebRTC infrastructure into Kubernetes.
The simplest way to deploy STUNner is through Helm. STUNner configuration
parameters are available for customization as Helm
Values.
helm repo add stunner https://l7mp.io/stunner
helm repo update
helm install stunner-gateway-operator stunner/stunner-gateway-operator --create-namespace \
--namespace=stunner-system
Find out more about the charts in the STUNner-helm repository.
Usage
STUNner comes with a wide selection of tutorials and demos that teach you how to deploy all kinds
of WebRTC services into Kubernetes. The first couple of tutorials present the basic concepts,
especially the use of the Kubernetes Gateway API to configure
STUNner and the turncat
utility to test it. Each subsequent demo
showcases a specific WebRTC application, from desktop streaming and video-conferencing to
cloud-gaming, and goes from a clean Kubernetes cluster to a working and usable publicly available
WebRTC service in 5-10 minutes using a purely declarative configuration.
- Deploying a UDP echo service behind STUNner: This
introductory tutorial shows how to deploy a simple UDP echo service into Kubernetes and expose it
via STUNner. If you read just one STUNner tutorial, this should be it.
- Opening a UDP tunnel via STUNner: This tutorial shows
how to tunnel an external UDP client via STUNner to a standard iperf server deployed into
Kubernetes. The demo can be used to benchmark your STUNner installation.
- Direct one to one video call via STUNner: This
tutorial showcases STUNner acting as a TURN server for two WebRTC clients to establish
connections between themselves, without the mediation of a media server.
- Video-conferencing with LiveKit: This tutorial helps you deploy
the LiveKit WebRTC media server behind STUNner. The docs also show how to
obtain a valid TLS certificate to secure your signaling connections, courtesy of the
cert-manager project, nip.io and Let's
Encrypt.
- Video-conferencing with Janus: This tutorial helps you deploy a
fully fledged Janus video-conferencing service into Kubernetes
behind STUNner. The docs also show how to obtain a valid TLS certificate to secure your signaling
connections, using cert-manager, nip.io and Let's
Encrypt.
- Video-conferencing with Elixir WebRTC: This tutorial helps
you deploy a fully fledged Elixir WebRTC video-conferencing room called
Nexus into Kubernetes
behind STUNner. The docs also show how to obtain a valid TLS certificate to secure your signaling
connections, using cert-manager, nip.io and Let's
Encrypt.
- Video-conferencing with Jitsi: This tutorial helps you deploy a
fully fledged Jitsi video-conferencing service into Kubernetes behind
STUNner. The docs also show how to obtain a valid TLS certificate to secure your signaling
connections, using cert-manager, nip.io and Let's
Encrypt.
- Video-conferencing with mediasoup: This tutorial helps you
deploy the mediasoup WebRTC media server behind STUNner. The docs also
show how to obtain a valid TLS certificate to secure your signaling connections, courtesy of the
cert-manager project, nip.io and Let's
Encrypt.
- Cloud-gaming with Cloudretro: This tutorial lets you play
Super Mario or Street Fighter in your browser, courtesy of the amazing
CloudRetro project and, of course, STUNner. The demo also presents a
simple multi-cluster setup, where clients can reach the game-servers in their geographical
locality to minimize latency.
- Remote desktop access with Neko: This demo showcases STUNner
providing an ingress gateway service to a remote desktop application. We use
neko.io to run a browser in a secure container inside the Kubernetes
cluster, and stream the desktop to clients via STUNner.
- One to one video call with Kurento: This tutorial
shows how to use STUNner to connect WebRTC clients to a media server deployed into Kubernetes
behind STUNner in the media-plane deployment model. All this happens
without modifying the media server code in any way, just by adding 5-10 lines of
straightforward JavaScript to configure clients to use STUNner as the TURN server.
- Magic mirror with Kurento: This tutorial has been
adopted from the Kurento magic
mirror
demo, deploying a basic WebRTC loopback server behind STUNner with some media processing
added. In particular, the application uses computer vision and augmented reality techniques to
add a funny hat on top of faces.
Documentation
The documentation of the stable release can be found here. The
documentation for the latest development release can be found here.
Milestones
- v0.9: Demo release: STUNner basic UDP/TURN connectivity + helm chart + tutorials.
- v0.10: Dataplane: Long-term STUN/TURN credentials and STUN/TURN over TCP/TLS/DTLS in standalone mode.
- v0.11: Control plane: Kubernetes gateway operator and dataplane reconciliation.
- v0.12: Security: Expose TLS/DTLS settings via the Gateway API.
- v0.13: Observability: Prometheus + Grafana dashboard.
- v0.15: Performance: Per-allocation CPU load-balancing for UDP
- v0.16: Management: Managed STUNner dataplane.
- v0.17: First release candidate: All Gateway and STUNner APIs move to v1.
- v0.18: Stabilization: Second release candidate.
- v0.19: The missing pieces: Third release candidate.
- v0.20: Final stabilization: Fourth stable release candidate
- v0.21: Towards v1: Fifth stable release candidate
- v1.0: STUNner goes GA!
Help
STUNner development is coordinated in Discord, feel free to join.
License
Copyright 2021-2023 by its authors. Some rights reserved. See AUTHORS.
MIT License - see LICENSE for full text.
Acknowledgments
Initial code adopted from pion/stun and
pion/turn.