docker-asterisk

A set of Dockerfiles for running asterisk (and a FastAGI, one for PHP as it stands)

Also checkout my blog article @ dougbtv.com.

You can pull the image from dockerhub.

Which is as simple as running:

# Asterisk 14
docker pull dougbtv/asterisk14

# Asterisk 13
docker pull dougbtv/asterisk13

# Asterisk 11
docker pull dougbtv/asterisk 

What is it based on?

Generally this is based on:

• Centos 7 base images
• Latest current available version of Asterisk certified branch (for LTS releases)

Dockerfile in the root directory is Asterisk 11 and available with docker pull dougbtv/asterisk

Looking for Asterisk 13 or 14?

• The Dockerfile is in asterisk/13/ or asterisk/14/

Check out the latest build!

The image is backed by bowline (a Docker build server, which I wrote) which watches for the latest tarball from downloads.asterisk.org, builds it into this docker image and then automatically pushes it to dockerhub.

Whenever a new build of Asterisk is created, the bot creates a pull request here, you can check out the latest merged pull requests. You'll see the results and logs of the image builds that are available via docker pull @ bowline.io

Bowline is under-work, but, was inspired by my Asterisk dockerfiles, seeing, it takes a while to compile Asterisk. (which is why it's nice to have an up-to-date image available)

Verified with CI using Travis

Check out the info on the latest build @ Travis-CI, it should give you a little confidence that the latest Dockerfile is building properly, and give you a little information about the build (for example, you can check out what modules are compiled in, a la module show). In short the Travis build has tests that ensure two instances of this Docker image can make a call between the two.

Don't be shy! Check out the .travis.yml file in the root and learn how to do it for yourself (it's not rocket science!)

Running it.

Asterisk with SIP tends to use a wide range of UDP ports (for RTP), so we have chosen to run the main aster container with --net=host option. We can now expose a range of ports with --expose=10000-20000, however, it can be very slow for a large number of ports.

We publish the port for the FastAGI container (which is running xinetd), and then we call the loopback address from AGI. You could separate these and run them on different hosts, should you choose.

An important function is that we need to access the CLI, which we use nsenter for, a shortcut script you'll run from the host is included here as tools/asterisk-cli.sh

This gist of how we get it going (and also memorialized in the tools/run.sh script) is:

NAME_ASTERISK=asterisk
NAME_FASTAGI=fastagi

# Run the fastagi container.
docker run \
    -p 4573:4573 \
    --name $NAME_FASTAGI \
    -d -t dougbtv/fastagi

# Run the main asterisk container.
docker run \
    --name $NAME_ASTERISK \
    --net=host \
    -d -t dougbtv/asterisk

However, this will run without any configuration what-so-ever, so you'll want to mount a volume with your configurations, a sample configuration is provided in this clone. So if your current working directory is this clone, you could mount the example configurations in /etc/asterisk however, I recommend you create your own configurations.

docker run \
    --name $NAME_ASTERISK \
    --net=host \
    -v $(pwd)/test/example/:/etc/asterisk/ \
    -d -t dougbtv/asterisk

Building it.

Just issue, with your current-working-dir as the clone:

docker build -t dougbtv/asterisk .
docker build -t dougbtv/fastagi fastagi/.

About it.

Let's inspect the important files in the clone

.
|-- Dockerfile
|-- extensions.conf
|-- fastagi/
|   |-- agiLaunch.sh
|   |-- agi.php
|   |-- Dockerfile
|   `-- xinetd_agi
|-- iax.conf
|-- modules.conf
|-- README.md
`-- tools/
    |-- asterisk-cli.sh
    |-- clean.sh
    `-- run.sh

In the root dir:

• Dockerfile what makes the dockerhub image dougbtv/asterisk
• extensions.conf a very simple dialplan
• iax.conf a sample iax.conf which sets up an IAX2 client (for testing, really)

The fastagi/ dir:

• Dockerfile creates a Docker image that runs xinetd
• xinetd_agi the configuration for xinetd to run agiLaunch.sh
• agiLaunch.sh a shell script to kick off our xinetd process (a php script)
• agi.php a sample AGI script, replace this with your main AGI php processes

In the tools/ dir are some utilities I find myself using over and over:

• asterisk-cli.sh runs the nsenter command (note: image name must contain "asterisk" for it to detect it, easy enough to modify to fit your needs)
• clean.sh kills all containers, and removes them.
• run.sh a suggested way to run the Docker container.

...Not listed is the asterisk/ dir, where there's a sample build for Asterisk 13 beta. This Dockerfile works. Just getting the ducks in a row for when it's released.

Bowline

This bot is backed by bowline, which is a Docker build server / application, that I also wrote. It's actually while making these files I was inspired to build this.

This ensures there's a fresh image built and available on Dockerhub. There used to be a prototype here, alas, I have removed it -- I recommend checking out bowline if you're interested.

Lessons Learned

• I needed to disable the BUILD_NATIVE compiler flag. Without asterisk would throw an illegal instruction when run in a new place.
  • This stackexchange answer helped. Thanks arheops
  • Also this note about Asterisk 11 release provides some reference, too.