How to Setup a Coturn Docker Image

MeetrixIO team is well experienced with WebRTC related technologies. We provide commercial support for Jitsi Meet, Kurento, OpenVidu, BigBlue Button, Coturn Server and other webRTC related opensource projects.

Long Term Credential Mechanism

Most of the webRTC libraries including SimpleWebRTC, SpreedWebRTC requires the turn server to be configured in long-term credentials mechanism. When a turn server is installed, we can start the turn server with long term credentials mechanism using -a flag and we can pass the shared secret like this.

--static-auth-secret=mysecret

Following is a complete command to run the turn server

turnserver -a -v -L 0.0.0.0 --server-name coturn --static-auth-secret=mysecret --realm=north.gov  -p 3478 --min-port 10000 --max-port 20000

-a is to enable long-tern-credentials machanism.
-v means the verbose mode.
With -L we can specify the ip address that the turn-server listen.

Other parameters have obvious meanings as in their names.

Containerization

Now, lets setup Coturn inside a docker container. Create directory named CoturnDocker and create a Dockerfile with following content inside that directory.

FROM Ubuntu:16.04
MAINTAINER Buddhika Jayawardhana <jay@meetrix.io>

RUN apt-get update && apt-get install -y coturn && apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*

ENV TURN_PORT 3478
ENV TURN_PORT_START 10000
ENV TURN_PORT_END 20000
ENV TURN_SECRET mysecret
ENV TURN_SERVER_NAME coturn
ENV TURN_REALM north.gov

ADD start_coturn.sh start_coturn.sh
RUN chmod +x start_coturn.sh

CMD ["./start_coturn.sh"]

Here we have defined 6 environmental variables to be used in start_coturn.sh file. Then create the start_coturn.sh file inside the same directory with following content.

#!/bin/bash

echo "Starting TURN/STUN server"

turnserver -a -v -L 0.0.0.0 --server-name "${TURN_SERVER_NAME}" --static-auth-secret="${TURN_SECRET}" --realm=${TURN_REALM}  -p ${TURN_PORT} --min-port ${TURN_PORT_START} --max-port ${TURN_PORT_END} ${TURN_EXTRA}

Now it's build time. Run following command to build the image inside CoturnDocker directory. Dont forget the trailing period

docker build -t coturn-long-term-cred .

Lets spin up a container from this image.

docker run --net=host --name my-coturn -t coturn-long-term-cred

with --net=host we are instructing to use the host network instead of docker network. This is needed for Coturn to operate properly.

Testing

To test whether our coturn server works as a perfect turn server, first we need to generate username and password. The algorithm is described in coturn wiki. Following shell script will generate the username and password when you provide the secret (mysecret in this case).

secret=mysecret && \
time=$(date +%s) && \
expiry=8400 && \
username=$(( $time + $expiry )) &&\
echo username:$username && \
echo password : $(echo -n $username | openssl dgst -binary -sha1 -hmac $secret | openssl base64)

output of this script would be some thing like following

username:1525325424
password : YuzkH/Th9BBaRj4ivR03PiCfr+E=

Now go to trickle ice page to test our turn server. If there any existing ICE servers remove them. Then input your turn server URI, username and password. Turn server URI should be in following format.

turn:<YOUR_SERVER_IP>:<YOUR_SERVER_PORT>

for example

turn:1.2.3.4:3478

For Username and Password enter the respective outputs from the above bash script. Then click Add Server button and press Gather candidates button. If you are getting a message saying Done, you have successfully configured the turn server.

Pushing the image to Docker Hub

After the image is built run the following command to find out the image id.

docker images | grep coturn-long-term-cred

You'll find something like this as the output

coturn-long-term-cred      latest              8bd04b84d978        About a minute ago   138MB

copy that id (8bd04b84d978 in this case).

Then tag the image with your docker hub user name

docker tag 8bd04b84d978 meetrix/coturn-long-term-cred:latest

docker login
docker push meetrix/coturn-long-term-cred:latest

Source Code & Docker Image

Sourcecode for this guide can be found at meetrix github repo Public Docker image for this project has been published to meetrix docker hub account

Looking for commercial support ? Please contact us via hello@meetrix.io