docs: How to deploy Jitsi (and potentially other examples) into DOKS about stunner

[rg0now]

Nice, thanks. What about adding a new subsection to the Jitsi tutorial README, something along the lines of "Enable health-checking" or similar?

Some notes:

• With the new (yet unreleased) version of STUNner you can add per-Gateway annotations: any annotation added to the Gateway will be automatically added to the LB service created by the STUNner operator to expose the Gateway. Gateway annotations override GatewayConfig.Spec.LoadBalancerServiceAnnotations on conflict.

apiVersion: stunner.l7mp.io/v1alpha1
kind: GatewayConfig
metadata:
  name: stunner-gatewayconfig
  namespace: stunner
spec:
  authType: longterm
  sharedSecret: "my-shared-secret"
---
apiVersion: gateway.networking.k8s.io/v1alpha2
kind: Gateway
metadata:
  name: udp-gateway
  namespace: stunner
  annotations:
    service.beta.kubernetes.io/do-loadbalancer-healthcheck-port: "8086"
    service.beta.kubernetes.io/do-loadbalancer-healthcheck-protocol: "http"
    service.beta.kubernetes.io/do-loadbalancer-healthcheck-path: "/live"
spec:
  gatewayClassName: stunner-gatewayclass
  listeners:
    - name: health-check
      port: 8086
      protocol: TCP
    - name: udp-listener
      port: 3478
      protocol: UDP

• Multiprotocol LB services are not supported as of now, since support is fairly uneven across Kubernetes versions. The STUNner operator will remove the TCP service-port from the LB service it creates, leaving only the UDP port in. This means you will have to create the LB service to expose the Gateway manually: just copy the Service created by STUNner and add the missing service-ports.

• In order to avoid having two LB Services for the Gateway (one created automatically and the manual copy), which usually costs extra $$$, we can fix the type of the service created by STUNner to ClusterIP by adding the special annotation stunner.l7mp.io/service-type: ClusterIP to the Gateway (or to the GatewayConfig loadBalancerServiceAnnotations but that will affect all services created by STUNner). This will still create a service but the type will be ClusterIP so it will not be exposed to the Internet, and this usually does not cause extra $$$.

apiVersion: gateway.networking.k8s.io/v1alpha2
kind: Gateway
metadata:
  name: udp-gateway
  namespace: stunner
  annotations:
    stunner.l7mp.io/service-type: ClusterIP
    service.beta.kubernetes.io/do-loadbalancer-healthcheck-port: "8086"
    service.beta.kubernetes.io/do-loadbalancer-healthcheck-protocol: "http"
    service.beta.kubernetes.io/do-loadbalancer-healthcheck-path: "/live"
spec:
  gatewayClassName: stunner-gatewayclass
  listeners:
    - name: health-check
      port: 8086
      protocol: TCP
    - name: udp-listener
      port: 3478
      protocol: UDP

[rg0now]

Closing this due to inactivity. Feel free to reopen if the problem persists.