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STUNner demo: Video-conferencing with Janus

This document guides you through the installation of Janus by Meetecho into Kubernetes, when it is used together with the STUNner WebRTC media gateway.

In this demo you will learn to:

  • integrate a typical WebRTC application with STUNner,
  • obtain a valid TLS certificate to secure the signaling plane,
  • deploy the Janus WebRTC server into Kubernetes, and
  • configure STUNner to expose Janus to clients.

Prerequisites

The below installation instructions require an operational cluster running a supported version of Kubernetes (>1.22). Most hosted or private Kubernetes cluster services will work, but make sure that the cluster comes with a functional load-balancer integration (all major hosted Kubernetes services should support this). Otherwise, STUNner will not be able to allocate a public IP address for clients to reach your WebRTC infra. As a regrettable exception, Minikube is unfortunately not supported for this demo. The reason is that Let's Encrypt certificate issuance is not available with nip.io; later on you will learn more about why this is crucial above.

Setup

The recommended way (or at least the possible way, link, link) to install Janus into Kubernetes is deploying the media servers into the host-network namespace of the Kubernetes nodes (hostNetwork: true). This deployment model, however, comes with a set of uncanny operational limitations and security concerns. Using STUNner, however, media servers can be deployed into ordinary Kubernetes pods and run over a private IP network, like any "normal" Kubernetes workload.

The figure below shows Janus deployed into regular Kubernetes pods behind STUNner without the host-networking hack. Here, Janus is deployed behind STUNner in the media-plane deployment model, so that STUNner acts as a "local" STUN/TURN server for Janus, saving the overhead of using public a 3rd party STUN/TURN server for NAT traversal.

STUNner Janus integration deployment architecture

In this tutorial we deploy Janus Gateway with a set of preimplemented and packaged server plugins for media exchange, a Janus Web Demo, a Kubernetes Ingress gateway to secure signaling connections and handle TLS, and STUNner as a media gateway to expose the Janus server pool to clients.

Installation

Note

Let's start with a disclaimer. The Janus client-side application must work over a secure HTTPS connection, because getUserMedia is available only in secure contexts. This implies that the client-server signaling connection must be secure too. In this demo, we will aim to obtain a proper CA-signed certificate (self-signed certificates haven't been tested). Obtaining a valid TLS certificate is a challenge. Thus, the majority of the below installation guide will be about securing client connections to Janus over TLS; as it turns out, once HTTPS is correctly working integrating Janus with STUNner is very simple.

In the below example, STUNner will be installed into the identically named namespace (stunner), while Janus and the Ingress gateway will live in the default namespace.

Docker images

Janus does not come with an official Docker image; thus, we built one using a self-made Dockerfile based on the available documents in the official Janus repository. Actually, we've made two Dockerfiles. One for the Janus Gateway server and one for the Janus Web Demos. The Janus Gateway server Dockerfile should be ran in the root directory of the Janus repository. The Janus Web Demos Dockerfile should be used in the /html directory of the same repository. The images (l7mp/janus-gateway:v1.2.4 and l7mp/janus-web:latest) used in the following demo are hosted on Docker Hub under the L7MP organization.

TLS certificates

As mentioned above, the Janus WebRTC server will need a valid TLS cert, which means it must run behind an existing DNS domain name backed by a CA signed TLS certificate. This is simple if you have your own domain, but if you don't then nip.io provides a dead simple wildcard DNS for any IP address. We will use this to "own a domain" and obtain a CA signed certificate for Janus. This will allow us to point the domain name client-<ingress-IP>.nip.io to an ingress HTTP gateway in our Kubernetes cluster, which will then use some automation (namely, cert-manager) to obtain a valid CA signed cert.

Note that public wildcard DNS domains might run into rate limiting issues. If this occurs you can try alternative services instead of nip.io.

Ingress

The first step of obtaining a valid cert is to install a Kubernetes Ingress: this will be used during the validation of our certificates and to terminate client TLS encrypted contexts.

Install an ingress controller into your cluster. We used the official nginx ingress, but this is not required.

helm repo add ingress-nginx https://kubernetes.github.io/ingress-nginx
helm repo update
helm install ingress-nginx ingress-nginx/ingress-nginx

Wait until Kubernetes assigns an external IP to the Ingress.

until [ -n "$(kubectl get service ingress-nginx-controller -o jsonpath='{.status.loadBalancer.ingress[0].ip}')" ]; do sleep 1; done

Store the Ingress IP address Kubernetes assigned to our Ingress; this will be needed later when we configure the validation pipeline for our TLS certs.

kubectl get service ingress-nginx-controller -o jsonpath='{.status.loadBalancer.ingress[0].ip}'
export INGRESSIP=$(kubectl get service ingress-nginx-controller -o jsonpath='{.status.loadBalancer.ingress[0].ip}')
export INGRESSIP=$(echo $INGRESSIP | sed 's/\./-/g')

Cert manager

We use the official cert-manager to automate TLS certificate management.

Add the Helm repository, which contains the cert-manager Helm chart, and install the charts:

helm repo add cert-manager https://charts.jetstack.io
helm repo update
helm install cert-manager jetstack/cert-manager --namespace cert-manager \
    --create-namespace --set global.leaderElection.namespace=cert-manager \
    --set crds.enabled=true --timeout 600s

At this point we have all the necessary boilerplate set up to automate TLS issuance for Janus.

STUNner

Now comes the fun part. The simplest way to run this demo is to clone the STUNner git repository and deploy (after some minor modifications) the manifest packaged with STUNner.

Install the STUNner gateway operator and STUNner via Helm:

helm repo add stunner https://l7mp.io/stunner
helm repo update
helm install stunner-gateway-operator stunner/stunner-gateway-operator --create-namespace --namespace=stunner

Configure STUNner to act as a STUN/TURN server to clients, and route all received media to the Janus Gateway pods.

git clone https://github.com/l7mp/stunner
cd stunner
kubectl apply -f docs/examples/janus/janus-call-stunner.yaml

The relevant parts here are the STUNner Gateway definition, which exposes the STUNner STUN/TURN server over UDP:3478 to the Internet, and the UDPRoute definition, which takes care of routing media to the pods running the Janus Gateway service.

apiVersion: gateway.networking.k8s.io/v1
kind: Gateway
metadata:
  name: udp-gateway
  namespace: stunner
spec:
  gatewayClassName: stunner-gatewayclass
  listeners:
    - name: udp-listener
      port: 3478
      protocol: UDP
---
apiVersion: stunner.l7mp.io/v1
kind: UDPRoute
metadata:
  name: janus
  namespace: stunner
spec:
  parentRefs:
    - name: udp-gateway
  rules:
    - backendRefs:
        - kind: Service
          name: janus-gateway
          namespace: default

Once the Gateway resource is installed into Kubernetes, STUNner will create a Kubernetes LoadBalancer for the Gateway to expose the TURN server on UDP:3478 to clients. It can take up to a minute for Kubernetes to allocate a public external IP for the service.

Wait until Kubernetes assigns an external IP and store the external IP assigned by Kubernetes to STUNner in an environment variable for later use.

until [ -n "$(kubectl get svc udp-gateway -n stunner -o jsonpath='{.status.loadBalancer.ingress[0].ip}')" ]; do sleep 1; done
export STUNNERIP=$(kubectl get service udp-gateway -n stunner -o jsonpath='{.status.loadBalancer.ingress[0].ip}')

Janus

The crucial step of integrating any WebRTC media server with STUNner is to ensure that the server instructs the clients to use STUNner as the STUN/TURN server. In order to achieve this, first we patch the public IP address of the STUNner STUN/TURN server we have learned above into our Janus Web and Gateway deployment manifests:

sed -i "s/stunner_ip/$STUNNERIP/g" docs/examples/janus/janus-server.yaml

Janus Web tells the connected clients where to look for the Janus Gateway server and which ICE servers should be used for ICE negotiation. Assuming that Kubernetes assigns the IP address 1.2.3.4 to STUNner (i.e., STUNNERIP=1.2.3.4), the relevant part of the Janus Web config would be something like the below:

...
  settings.js: |
    var server = "wss://server-$INGRESSIP.nip.io"
    var iceServers = [{urls: "turn:1.2.3.4:3478?transport=udp", username: "user-1", credential: "pass-1"}]

This will make sure that Janus Web tells the clients to use STUNner as the STUN/TURN server. If unsure about the STUNner settings to use, you can always use the handy stunnerctl CLI tool to dump the running STUNner configuration.

stunnerctl -n stunner config udp-gateway
Gateway: stunner/udp-gateway (loglevel: "all:INFO")
Authentication type: static, username/password: user-1/pass-1
Listeners:
  - Name: stunner/udp-gateway/udp-listener
    Protocol: TURN-UDP
    Public address:port: 34.118.88.91:3478
    Routes: [stunner/iperf-server]
    Endpoints: [10.76.1.4, 10.80.4.47]

Note that Janus itself will not use STUNner as a TURN server (that would amount to a less efficient symmetric ICE mode); with the above configuration we are just telling Janus Web to instruct its clients to use STUNner to reach the Janus Gateway server.

We also need the Ingress external IP address we have stored previously: this will make sure that the TLS certificate created by cert-manager will be bound to the proper nip.io domain and IP address.

sed -i "s/ingressserviceip/$INGRESSIP/g" docs/examples/janus/janus-server.yaml

Finally, fire up Janus.

kubectl apply -f docs/examples/janus/janus-server.yaml

The demo installation bundle includes a lot of resources to deploy Janus:

  • a Janus Gateway server,
  • a web server serving the landing page using Janus Web Demos
  • a cluster issuer for the TLS certificates,
  • an Ingress resource to terminate the secure connections between your browser and the Kubernetes cluster.

Wait until all pods become operational and jump right into testing!

Test

After installing everything, execute the following command to retrieve the URL of your freshly deployed Janus demo app:

echo client-$INGRESSIP.nip.io

Copy the URL into your browser, and now you should be greeted with the About page. On the landing page navigate to the Video call plugin demo (/demos/videocall.html). Duplicate the tab and register two users in the system and make a call. If everything is set up correctly, you should be able to connect to a room. If you repeat the procedure in a separate browser tab you can enjoy a nice video-conferencing session with yourself, with the twist that all media between the browser tabs is flowing through STUNner and the Janus Gateway server deployed in you Kubernetes cluster.

Help

STUNner development is coordinated in Discord, feel free to join.