Using the Autopilot pattern to deploy container resources at a WLCG Tier-2

Containers are becoming ubiquitous within the WLCG, with CMS announcing a requirement for its sites to provide Singularity during 2018. The ubiquity of containers means it is now possible to reify the combination of an application and its configuration into a single easy-to-deploy unit, avoiding the need to make use of a myriad of configuration management tools such as Puppet, Ansible or Salt. This allows use to be made of industry-standard devops techniques within the operations domain, such as Continuous Integration (CI) and Continuous Deployment (CD), which can lead to faster upgrades and greater system security. One interesting technique is the Autopilot pattern, which provides mechanisms for application life-cycle management which are accessible from within the container itself. Using modern service discovery techniques, each container manages its own configuration, monitors its own health, and adapts to changing requirements through the use of event triggers. In this paper, we expand on previous work to create and deploy resources to a WLCG Tier-2 via containers, and investigate the viability of using the Autopilot pattern at a WLCG site to deploy and manage computational resources.