For developing or testing out Singularity with Docker, you will need to install docker and docker-compose.

Example cluster with Docker Compose

Run docker-compose pull first to get all of the needed images. Note: This may take a few minutes

Then simply run docker-compose up and it will start containers for...

  • mesos master
  • mesos agent (docker/mesos containerizers enabled)
  • zookeeper
  • Singularity
  • Baragon Service for load balancer management
  • Baragon Agent + Nginx as a load balancer

...and the following UIs will be available:

if using boot2docker or another vm, replace localhost with the ip of your vm

The docker-compose example clsuter will always run off of the most recent release tag.

Developing With Docker


In the root of this project is a dev wrapper script to make developing easier. It will run using images from the current snapshot version. You can do the following:

./dev pull           # Get the latest images from docker hub
./dev start          # start mesos clsuter in background
./dev attach         # start mesos cluster and watch output in console
./dev restart        # stop all containers and restart in background
./dev rebuild        # stop all containers, rebuild Singularity and docker images, then start in background
./dev rebuild attach # rebuild and watch output when started
./dev remove         # remove stopped containers
./dev stop           # stop all containers
./dev kill           # kill all containers (ungraceful term)

The output from the dev script will give you information about where the SingularityUI can be reached.

Building new images

Singularity uses the docker-maven-plugin for building its images. There are a few images related to Singularity:

  • hubspot/singularityservice - The Singularity scheduler itself
  • hubspot/singularityexecutorslave - A mesos agent with java/logrotate and the custom SingularityExecutor installed
  • hubspot/singularitybase - A base image for singularityexecutorslave that takes care of installing java/logrotate/etc on top of the mesos agent image (not built with maven plugin)

Logs and Entering Containers

If you are not attached to the docker-compose process, you can check the output of your containers using docker logs. Start by checking docker ps to see what containers are running. Generally they will have names like singularity_(process name). From there you can run docker logs (name) to see the stdout for that container.

Need to see more than stdout? You can also get a shell inside the container and poke around. Once you know the name of your container, you can run docker exec -it (name) /bin/bash to get am interactive shell inside the running container.

Integration Tests

The SingularityServiceIntegrationTests module will run tests on a cluster consisting of a singularity scheduler, zk instance, mesos master, and three mesos agents. These will run during the integration-test lifecycle phase.