RTCD Setup and Configuration

This guide provides detailed instructions for setting up, configuring, and validating a Mattermost Calls deployment using the dedicated RTCD service.

Prerequisites

Before deploying RTCD, ensure you have:

A Mattermost Enterprise license
A server or VM with sufficient CPU and network capacity (see the Performance baselines section for sizing guidance)

Network Requirements

The following network connectivity is required:

Installation and Deployment

There are multiple ways to deploy RTCD, depending on your environment. We recommend the following order based on production readiness and operational control:

Bare Metal or VM Deployment (Recommended)

This is the recommended deployment method for non-Kubernetes production environments, as it provides the best performance and operational control. For Kubernetes deployments, see the Calls Deployment on Kubernetes guide.

<Tip>

Looking for an automated setup? Check out these community-maintained Calls Installation Scripts for quick provisioning of the RTCD service on Ubuntu/Debian systems.

</Tip>

Download and install the RTCD binary:

Download the latest release from the RTCD GitHub repository:

bash

# Create the RTCD directory structure
sudo mkdir -p /opt/rtcd

# Download the latest RTCD binary (adjust URL for your architecture)
# For Linux x86_64:
wget https://github.com/mattermost/rtcd/releases/latest/download/rtcd-linux-amd64

# Make the binary executable and move it to the installation directory
chmod +x rtcd-linux-amd64
sudo mv rtcd-linux-amd64 /opt/rtcd/rtcd

{note}

Replace `rtcd-linux-amd64` with the appropriate binary for your system architecture (e.g., `rtcd-linux-arm64` for ARM64 systems). The binary should be placed at `/opt/rtcd/rtcd` as this is the expected location referenced in systemd service files and other documentation.

Create a configuration file (/opt/rtcd/rtcd.toml):

Mattermost recommends using the official config.sample.toml as a starting point. Download this file and use it as your base configuration.

Create a dedicated user for the RTCD service:

bash

sudo useradd --system --no-create-home --shell /bin/false mattermost

Create the data directory and set ownership:

bash

sudo mkdir -p /opt/rtcd/data/db
sudo chown -R mattermost:mattermost /opt/rtcd

Create a systemd service file (/etc/systemd/system/rtcd.service):

ini

[Unit]
Description=Mattermost RTCD Server
After=network.target

[Service]
Type=simple
User=mattermost
Group=mattermost
ExecStart=/opt/rtcd/rtcd --config /opt/rtcd/rtcd.toml
Restart=always
RestartSec=10
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target

Enable and start the service:

bash

sudo systemctl daemon-reload
sudo systemctl enable rtcd
sudo systemctl start rtcd

Check the service status:
bash
```
sudo systemctl status rtcd
```

Docker Deployment

Docker deployment is suitable for development, testing, or containerized production environments:

Run the RTCD container with basic configuration:

bash

docker run -d --name rtcd \
  -e "RTCD_LOGGER_ENABLEFILE=true" \
  -p 8443:8443/udp \
  -p 8443:8443/tcp \
  -p 8045:8045/tcp \
  mattermost/rtcd:latest

{note}

If you optionally use the `RTCD_API_SECURITY_ALLOWSELFREGISTRATION` setting, please note that it defaults to `false`. If enabled, it allows anyone who can connect to the service on the API port (8045) to successfully initiate calls. Understand the security implications of this setting before enabling it.

For debugging purposes, you can enable more detailed logging:

bash

docker run -d --name rtcd \
  -e "RTCD_LOGGER_ENABLEFILE=true" \
  -e "RTCD_LOGGER_CONSOLELEVEL=DEBUG" \
  -p 8443:8443/udp \
  -p 8443:8443/tcp \
  -p 8045:8045/tcp \
  mattermost/rtcd:latest

To view the logs:

bash

docker logs -f rtcd

You can also use a mounted configuration file instead of environment variables:

bash

docker run -d --name rtcd \
  -p 8045:8045 \
  -p 8443:8443/udp \
  -p 8443:8443/tcp \
  -v /path/to/config.toml:/rtcd/config/config.toml \
  mattermost/rtcd:latest

For a complete sample configuration file, see the RTCD config.sample.toml in the official repository.

Kubernetes Deployment

For detailed information on deploying RTCD in Kubernetes environments, including Helm chart configurations, resource requirements, and scaling considerations, see the Calls Deployment on Kubernetes guide.

Configuration

RTCD Configuration File

The RTCD service uses a TOML configuration file. Mattermost recommends using the official config.sample.toml as your base configuration file.

<Note>

A notable setting to be aware of is ice_host_override under the [rtc] section. You may need to configure this setting explicitly, particularly when RTCD is deployed behind NAT, in complex network topologies, or when automatic address discovery via STUN is unreliable. Setting ice_host_override directly to your server's public IP address or hostname is the preferred approach.

</Note>

TURN Configuration

For clients behind strict firewalls, you may need to configure TURN servers. In the RTCD configuration file, reference your TURN servers as follows:

toml

[rtc]
# TURN server configuration
   ice_servers = [
     { urls = ["turn:turn.example.com:3478"], username = "turnuser", credential = "turnpassword" }
   ]

We recommend using coturn for your TURN server implementation.

System Tuning

For high-volume deployments, tune your Linux system:

Add the following to /etc/sysctl.conf:

bash

# Increase UDP buffer sizes
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.core.optmem_max = 16777216

Apply the settings:
bash
```
sudo sysctl -p
```

Validation and Testing

After deploying RTCD, validate the installation:

Check service status and version:

bash

curl http://YOUR_RTCD_SERVER:8045/version
# Should return a JSON object with service information
# Example: {"build_hash":"abc123","build_date":"2023-01-15T12:00:00Z","build_version":"0.11.0","goVersion":"go1.20.4"}

Test UDP connectivity:

Before testing, ensure the RTCD service is stopped, as it binds to the same port.
bash
```
sudo systemctl stop rtcd
```
On the RTCD server:
bash
```
sudo ncat -u -l -k -p 8443 -c '/bin/cat'
```
On a client machine:
bash

sudo nmap -sU -p 8443 RTCD_SERVER_IP

   
If UDP connectivity is working, `nmap` reports as `open`.

Restart RTCD after the test:

```bash
sudo systemctl start rtcd

Test TCP connectivity (if enabled):

Run this check from a client machine:
bash
```
nmap -p 8443 RTCD_SERVER_IP
```
If TCP fallback is enabled and reachable, nmap reports as open.
Monitor metrics:

Refer to Calls Metrics and Monitoring for setting up Calls metrics and monitoring.

Horizontal Scaling

To scale RTCD horizontally:

Deploy multiple RTCD instances:

Deploy multiple RTCD servers, each with their own unique IP address.

Configure DNS record:

Set up a DNS record that points to multiple RTCD IP addresses:

bash

rtcd.example.com.    IN A    10.0.0.1
rtcd.example.com.    IN A    10.0.0.2
rtcd.example.com.    IN A    10.0.0.3

Configure health checks:

Set up health checks to automatically remove unhealthy RTCD instances from DNS.
Configure Mattermost:

In the Mattermost System Console, set the RTCD Service URL to your DNS name (e.g., rtcd.example.com).

When a call starts, the Mattermost server examines the available RTCD servers (via the configured DNS record) and starts the call on the RTCD server with the lowest CPU usage. All participants in the call will connect to that RTCD server; a single call cannot be shared across multiple servers.

Integration with Mattermost

Once RTCD is properly set up and validated, configure Mattermost to use it:

Go to System Console > Plugins > Calls
Set the RTCD Service URL to your RTCD service address (either a single server or DNS load-balanced hostname). Ensure you provide any generated credentials formulated in the URI (e.g., http://clientID:[email protected]).
Save the configuration
Test by creating a new call in any Mattermost channel
Verify that the call is being routed through RTCD by checking the RTCD logs and metrics

Prerequisites

Network Requirements

Installation and Deployment

Bare Metal or VM Deployment (Recommended)

Docker Deployment

Kubernetes Deployment

Configuration

RTCD Configuration File

TURN Configuration

System Tuning

Validation and Testing

Horizontal Scaling

Integration with Mattermost

Other Calls Documentation