feat: coturn TURN-relay + bandwidth defaults for mobile

Adds a coturn pod that gives clients a relay path when direct UDP to
JVB:10001 doesn't make it through carrier NAT (the typical mobile-data
failure mode the user hit). Same domain as the rest — meet.it.financeflow.de
— because TURN ports (3478/5349) don't collide with the Ingress on 443.

- 80-coturn.yaml: hostNetwork Deployment binding STUN+TURN on 3478
  (UDP/TCP) and TURNS on 5349 (UDP/TCP), inline-templates turnserver.conf
  with PUBLIC_IP + TURN_CREDENTIALS_SECRET. TLS cert mounted from the
  same jitsi-tls Secret cert-manager already manages for the web Ingress.
  CronJob restarts coturn weekly so cert renewals propagate.
- 10-config.yaml: STUN now points at our own coturn; TURN_HOST/TURNS_HOST
  set so Prosody mod_external_services hands TURN endpoints to clients
  during XMPP session init. RESOLUTION capped at 480p,
  START_VIDEO_MUTED=5 keeps large rooms light on bandwidth.
- generate-secrets.sh + 20-secrets.yaml.example: TURN_CREDENTIALS_SECRET
  added so Prosody and coturn share the HMAC key (already pre-synced
  out-of-band into the cluster).
- deploy.yml: sed __PUBLIC_IP__ in coturn manifest, rollout-status coturn.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

.gitea/workflows/deploy.yml

@@ -25,13 +25,13 @@ jobs:
           chmod 600 "$HOME/.kube/config"
           kubectl config current-context
 
-      # __PUBLIC_IP__ placeholder in jvb manifest needs the actual public
-      # IP of darkember. Inject from a repo secret so the manifest stays
-      # generic in git.
-      - name: Patch JVB public IP
+      # __PUBLIC_IP__ placeholder lives in JVB + coturn manifests — both
+      # advertise their public address so clients can reach them. Single
+      # sed pass over the directory keeps the secret out of git.
+      - name: Patch __PUBLIC_IP__ in manifests
         run: |
           test -n "${{ secrets.DARKEMBER_PUBLIC_IP }}" || (echo "secret DARKEMBER_PUBLIC_IP missing" && exit 1)
-          sed -i "s|__PUBLIC_IP__|${{ secrets.DARKEMBER_PUBLIC_IP }}|g" infra/k3s/60-jvb.yaml
+          sed -i "s|__PUBLIC_IP__|${{ secrets.DARKEMBER_PUBLIC_IP }}|g" infra/k3s/60-jvb.yaml infra/k3s/80-coturn.yaml
 
       - name: Apply manifests
         # 20-secrets.yaml is intentionally NOT applied — secret must be
@@ -45,6 +45,7 @@ jobs:
           kubectl apply -f infra/k3s/50-web.yaml
           kubectl apply -f infra/k3s/60-jvb.yaml
           kubectl apply -f infra/k3s/70-ingress.yaml
+          kubectl apply -f infra/k3s/80-coturn.yaml
 
       # ConfigMap-only changes don't restart pods on their own, so a
       # deploy that just edits 10-config.yaml would otherwise leave the
@@ -59,6 +60,7 @@ jobs:
           kubectl -n jitsi rollout status deployment/jicofo --timeout=3m
           kubectl -n jitsi rollout status deployment/jitsi-web --timeout=3m
           kubectl -n jitsi rollout status deployment/jvb --timeout=3m
+          kubectl -n jitsi rollout status deployment/coturn --timeout=3m
 
       - name: Smoke-check
         run: |

infra/k3s/10-config.yaml

@@ -43,8 +43,17 @@ data:
   # === Videobridge brewery (where jicofo finds JVBs over XMPP) ===
   JVB_BREWERY_MUC: "jvbbrewery"
 
-  # === STUN — default Jitsi-hosted STUN servers; ok for getting started ===
-  JVB_STUN_SERVERS: "meet-jit-si-turnrelay.jitsi.net:443"
+  # === STUN/TURN — our own coturn (deploy 80-coturn.yaml). JVB itself
+  # uses STUN to discover its public-side mapping; clients additionally
+  # learn the TURN endpoints from Prosody via mod_external_services and
+  # fall back to relay when direct UDP doesn't reach JVB:10001 (typical
+  # for mobile-carrier NATs). ===
+  JVB_STUN_SERVERS: "meet.it.financeflow.de:3478"
+  TURN_HOST: "meet.it.financeflow.de"
+  TURNS_HOST: "meet.it.financeflow.de"
+  TURN_PORT: "3478"
+  TURNS_PORT: "5349"
+  TURN_TRANSPORT: "udp,tcp"
 
   # === UX / lockdown ===
   # Pre-join page on — gives joiners a chance to set audio/video before
@@ -58,3 +67,12 @@ data:
   ENABLE_CLOSE_PAGE: "0"
   ENABLE_TRANSCRIPTIONS: "0"
   ENABLE_RECORDING: "0"
+
+  # === Bandwidth defaults — keep things sane on mobile ===
+  # Cap outgoing video at 480p so even slow connections can stream.
+  # Users on fat pipes can still manually bump it via the toolbar.
+  RESOLUTION: "480"
+  RESOLUTION_MIN: "180"
+  # In rooms with >5 people, new joiners start with video muted —
+  # saves bandwidth in larger team meetings, easy 1-click to enable.
+  START_VIDEO_MUTED: "5"

infra/k3s/20-secrets.yaml.example

@@ -25,3 +25,7 @@ stringData:
   #   kubectl -n embertime exec -it deploy/embertime-postgres -- \
   #     psql -U embertime -t -c "select meeting_jwt_secret from app_settings"
   JWT_APP_SECRET: "REPLACE_WITH_VALUE_FROM_EMBERTIME"
+  # HMAC secret shared between coturn and Prosody. Prosody mints
+  # time-limited TURN credentials; coturn validates with the same key.
+  # Generate fresh via generate-secrets.sh.
+  TURN_CREDENTIALS_SECRET: "REPLACE_WITH_32_RANDOM_CHARS"

infra/k3s/80-coturn.yaml

@@ -0,0 +1,162 @@
+# coturn — STUN+TURN relay for clients whose network can't reach JVB
+# directly. Hosted on the same node as JVB; hostNetwork: true so the
+# TURN listening ports bind on the public NIC. The TLS cert is the
+# same one cert-manager already issues for the jitsi-web Ingress —
+# we mount the jitsi-tls Secret as a volume. Watch out: when the cert
+# renews, this pod must be restarted to pick up the new file (the
+# weekly CronJob below handles that).
+#
+# Auth model: HMAC time-limited credentials. coturn validates with
+# `use-auth-secret` + `static-auth-secret=<TURN_CREDENTIALS_SECRET>`;
+# Prosody hands out matching credentials per session via
+# mod_external_services. Both read the secret from the same k8s
+# Secret entry so they stay in lockstep.
+#
+# Port plan (mirrors required FritzBox forwards):
+#   UDP 3478          STUN + TURN (cleartext)
+#   TCP 3478          TURN over TCP — first cleartext fallback
+#   UDP 5349          TURN over DTLS
+#   TCP 5349          TURN over TLS  — works through most firewalls
+#   UDP 50000-50100   relay range — actual media flows on these
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: coturn
+  namespace: jitsi
+spec:
+  replicas: 1
+  strategy:
+    type: Recreate
+  selector:
+    matchLabels: { app: coturn }
+  template:
+    metadata:
+      labels: { app: coturn }
+    spec:
+      hostNetwork: true
+      dnsPolicy: ClusterFirstWithHostNet
+      containers:
+        - name: coturn
+          image: coturn/coturn:4.7-alpine
+          # Inline-template the config so we can interpolate the env-var
+          # secret without an extra ConfigMap-then-envsubst dance.
+          command: ["/bin/sh", "-c"]
+          args:
+            - |
+              set -eu
+              cat > /tmp/turnserver.conf <<EOF
+              listening-port=3478
+              tls-listening-port=5349
+              listening-ip=0.0.0.0
+              external-ip=${PUBLIC_IP}
+              relay-ip=${PUBLIC_IP}
+              cert=/certs/tls.crt
+              pkey=/certs/tls.key
+              # Jitsi/Prosody hands out HMAC-signed time-limited creds
+              # using this same secret — coturn validates them.
+              use-auth-secret
+              static-auth-secret=${TURN_CREDENTIALS_SECRET}
+              realm=meet.it.financeflow.de
+              # Relay port range. Forward these on the router.
+              min-port=50000
+              max-port=50100
+              log-file=stdout
+              simple-log
+              no-loopback-peers
+              no-multicast-peers
+              no-tlsv1
+              no-tlsv1_1
+              fingerprint
+              # Don't allow relaying to internal addresses — TURN should
+              # only relay to the public internet.
+              denied-peer-ip=10.0.0.0-10.255.255.255
+              denied-peer-ip=172.16.0.0-172.31.255.255
+              denied-peer-ip=192.168.0.0-192.168.255.255
+              EOF
+              exec turnserver -c /tmp/turnserver.conf
+          env:
+            - name: PUBLIC_IP
+              value: "__PUBLIC_IP__"
+            - name: TURN_CREDENTIALS_SECRET
+              valueFrom:
+                secretKeyRef:
+                  name: jitsi-secrets
+                  key: TURN_CREDENTIALS_SECRET
+          ports:
+            - { name: stun-udp, containerPort: 3478, hostPort: 3478, protocol: UDP }
+            - { name: stun-tcp, containerPort: 3478, hostPort: 3478, protocol: TCP }
+            - { name: turns-udp, containerPort: 5349, hostPort: 5349, protocol: UDP }
+            - { name: turns-tcp, containerPort: 5349, hostPort: 5349, protocol: TCP }
+          volumeMounts:
+            - { name: tls, mountPath: /certs, readOnly: true }
+          resources:
+            requests: { cpu: 100m, memory: 128Mi }
+            limits: { cpu: 1, memory: 512Mi }
+      volumes:
+        - name: tls
+          secret:
+            secretName: jitsi-tls
+            items:
+              - { key: tls.crt, path: tls.crt }
+              - { key: tls.key, path: tls.key }
+---
+# Cert-manager renews the Let's-Encrypt cert ~30 days before expiry.
+# The Secret content updates automatically, but coturn keeps the old
+# in-memory cert until it's restarted. Restart once a week — Sundays
+# 03:00 — gives us plenty of slack vs. the 90-day cert lifetime and
+# 30-day renewal window.
+apiVersion: batch/v1
+kind: CronJob
+metadata:
+  name: coturn-cert-refresh
+  namespace: jitsi
+spec:
+  schedule: "0 3 * * 0"
+  concurrencyPolicy: Forbid
+  successfulJobsHistoryLimit: 1
+  failedJobsHistoryLimit: 2
+  jobTemplate:
+    spec:
+      template:
+        spec:
+          serviceAccountName: coturn-restarter
+          restartPolicy: OnFailure
+          containers:
+            - name: kubectl
+              image: bitnami/kubectl:1.30
+              command: ["/bin/sh", "-c"]
+              args:
+                - kubectl -n jitsi rollout restart deployment/coturn
+---
+# Minimal RBAC for the CronJob — only allows rolling-restart of the
+# coturn Deployment, nothing else. Scoped to the jitsi namespace.
+apiVersion: v1
+kind: ServiceAccount
+metadata:
+  name: coturn-restarter
+  namespace: jitsi
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: Role
+metadata:
+  name: coturn-restarter
+  namespace: jitsi
+rules:
+  - apiGroups: ["apps"]
+    resources: ["deployments"]
+    resourceNames: ["coturn"]
+    verbs: ["get", "patch"]
+---
+apiVersion: rbac.authorization.k8s.io/v1
+kind: RoleBinding
+metadata:
+  name: coturn-restarter
+  namespace: jitsi
+subjects:
+  - kind: ServiceAccount
+    name: coturn-restarter
+    namespace: jitsi
+roleRef:
+  kind: Role
+  name: coturn-restarter
+  apiGroup: rbac.authorization.k8s.io

scripts/generate-secrets.sh

@@ -17,6 +17,7 @@ rand() { openssl rand -hex 16; }  # 32 hex chars = 16 bytes entropy, plenty for
 JICOFO_COMPONENT_SECRET=$(rand)
 JICOFO_AUTH_PASSWORD=$(rand)
 JVB_AUTH_PASSWORD=$(rand)
+TURN_CREDENTIALS_SECRET=$(rand)
 
 cat <<EOF
 apiVersion: v1
@@ -31,4 +32,5 @@ stringData:
   JICOFO_AUTH_PASSWORD: "${JICOFO_AUTH_PASSWORD}"
   JVB_AUTH_USER: "jvb"
   JVB_AUTH_PASSWORD: "${JVB_AUTH_PASSWORD}"
+  TURN_CREDENTIALS_SECRET: "${TURN_CREDENTIALS_SECRET}"
 EOF