DOMjudge JudgeHost AMI Creation

This repository automates the creation of an Amazon AMI that is ready to run the DOMjudge JudgeHost(the sandbox evaluation portion). It basically installs the Judgehost and its dependencies into an Ubuntu 14.04 image and makes the judgedaemons configurable in a way we expect.

Please refer to the parent project for more details: https://github.com/ubergeek42/domjudge-aws

Dependencies

This script depends on boto3 to be present on your workstation.

Boto3

The python script depends on boto3 to communicate with the AWS API in order to provision a virtual machine, set it up, and then create an AMI out of it.

Install boto3

pip install boto3

You can also install this in a virtual environment if you'd like.

Configure Boto3

Follow the steps here: http://boto3.readthedocs.org/en/latest/guide/quickstart.html#configuration

Basically, run aws configure, or edit the file ~/.aws/credentials to contain:

[default]
aws_access_key_id = YOUR_ACCESS_KEY
aws_secret_access_key = YOUR_SECRET_KEY

Creating the AMI

Once you've set up boto3, you just need to run the createami.py script. When it finishes it will print out the AMI ID. That's it!

Note that this process may take 20+ minutes to run.

You may want to edit the createami.py file to specify your AWS region and base ami to start from. See comments in the file.

Additional Information

What's this thing actually do?

This script will launch an EC2 Virtual Machine. It instructs the VM to run Ansible after booting and to evaluate the local.yml playbook from this repository. After Ansible finishes, the Virtual Machine will power down.

While Ansible is doing it's thing on the VM the python script is simply waiting in a loop for the virtual machine to power off. Once it does so, the script will tell AWS to create an AMI based off that machine. The script waits for this process to complete, then deletes the virtual machine.

Finally it will print out the AMI ID. You'll need this when you set up your DOMjudge cluster.

You'll probably be charged for less than an hour's worth of EC2 time on a t2.micro instance. Once the ami is created you'll be charged for storage of the snapshot backing it. See the pricing page here for details: https://aws.amazon.com/ebs/pricing/

Ok, but what does the ansible portion do?

The ansible bit runs everything in local.yml. Right now that installs the DOMjudge Judgehost from the DOMjudge repository. It will then set up some init scripts so that the one JudgeDaemon will be started for each processor core, but making sure to leave one core free to the system. E.g on a 4 core system it will set up 3 JudgeDaemons. It will also make sure that the system is configured properly for cgroup support.

It will install all the necessary compilers and tools for various the various languages your contest might want to use. It will also set up the chroot environment with the necessary runtimes(python, java, c#). The java runtime used is Oracle Java 8.

Hacking

If you wish to modify this repository, feel free to do so, however note that you'll want to change the github url in the createami.py file to correspond to your repository instead of mine. If you don't change it when the ami creation process launches ansible it will continue to use my local.yml file.

If you need additional programming language support, you should probably edit local.yml to include the package for your particular language, and also the files/make_chroot script to install any necessary runtime libraries your code will need.

License

This repository is made available under the terms of the GPL v2 License(Since we make use of the make_chroot file from DOMjudge). See the LICENSE file for more details.