Add Jitsi support

docs/configuring-dns.md

@@ -23,6 +23,7 @@ If you decide to go with the alternative method ([Server Delegation via a DNS SR
 | A     | `matrix`                     | -        | -      | -    | `matrix-server-IP`     |
 | CNAME | `riot`                       | -        | -      | -    | `matrix.<your-domain>` |
 | CNAME | `dimension` (*)              | -        | -      | -    | `matrix.<your-domain>` |
+| CNAME | `jitsi` (*)                  | -        | -      | -    | `matrix.<your-domain>` |
 | SRV   | `_matrix-identity._tcp`      | 10       | 0      | 443  | `matrix.<your-domain>` |
 
 
@@ -38,6 +39,8 @@ If you'd rather instruct the playbook not to install Riot (`matrix_riot_web_enab
 
 The `dimension.<your-domain>` subdomain may be necessary, because this playbook could install the [Dimension integrations manager](http://dimension.t2bot.io/) for you. Dimension installation is disabled by default, because it's only possible to install it after the other Matrix services are working (see [Setting up Dimension](configuring-playbook-dimension.md) later). If you do not wish to set up Dimension, feel free to skip the `dimension.<your-domain>` DNS record.
 
+The `jitsi.<your-domain>` subdomain may be necessary, because this playbook could install the [Jitsi video-conferencing platform](https://jitsi.org/) for you. Jitsi installation is disabled by default, because it may be heavy and is not a core required component. To learn how to install it, see our [Jitsi](configuring-playbook-jitsi.md) guide. If you do not wish to set up Jitsi, feel free to skip the `jitsi.<your-domain>` DNS record.
+
 
 ## `_matrix-identity._tcp` SRV record setup
 

docs/configuring-playbook-jitsi.md

@@ -0,0 +1,39 @@
+# Jitsi
+
+The playbook can install the [Jitsi](https://jitsi.org/) video-conferencing platform and integrate it with [Riot](configuring-playbook-riot-web.md).
+
+Jitsi installation is **not enabled by default**, because it's not a core component of Matrix services.
+
+The setup done by the playbook is very similar to [docker-jitsi-meet](https://github.com/jitsi/docker-jitsi-meet).
+
+
+## Prerequisites
+
+Before installing Jitsi, make sure you've created the `jitsi.DOMAIN` DNS record. See [Configuring DNS](configuring-dns.md).
+
+You may also need to open the following ports to your server:
+
+- `udp/10000` - RTP media over UDP
+- `tcp/4443` - RTP media fallback over TCP
+
+
+## Installation
+
+Add this to your `inventory/host_vars/matrix.DOMAIN/vars.yml` configuration:
+
+```yaml
+matrix_jitsi_enabled: true
+
+# We only need this temporarily - until Jitsi integration in riot-web is finalized.
+# Remove this line in the future, to switch back to a stable riot-web version.
+matrix_riot_web_docker_image: "vectorim/riot-web:develop"
+```
+
+Then re-run the playbook: `ansible-playbook -i inventory/hosts setup.yml --tags=setup-all,start`
+
+.. and fully reload your riot-web page (at `riot.DOMAIN`).
+
+Starting a video-conference in a room with more than 2 members should then create a Jitsi widget which utilizes your self-hosted Jitsi server.
+
+
+**NOTE**: the playbook currently configures the Jitsi JVB component to use Google's STUN servers even in cases where our own [Coturn TURN server](configuring-playbook-turn.md) is enabled (it is by default). This is because JVB fails to discover its own external IP correctly when pointed to our own Coturn server. The failure happens because JVB reaches Coturn via the localnetwork and discovers a local Docker IP address instead of the public one, leading to a non-working service.