Apache ARIA Service Proxy Plugin

Introduction

The Apache ARIA project, is an OASIS TOSCA Simple YAML 1.0 reference implementation that includes a CLI and orchestration/execution engine. With it, TOSCA YAML service templates can be parsed and validated, instantiated, and have workflows run against them. Like Cloudify, the orchestration engine is extensible via plugins. This post is about the implementation and features of one such plugin which has a similar counterpart in Cloudify, the ARIA Service Proxy Plugin.

Rationale

TOSCA concerns itself with defining service templates, which contain a model of a given deployment structure or stack. TOSCA also defines normative operations (e.g. create, configure, start..) for template components (nodes) which an orchestrator can call to produce desired effects (e.g. install, uninstall). TOSCA also define a form of template composition known as substitution mapping. Substitution mapping permits the construction of service templates that can expose a simple interface for reference by other service templates. For example, a database service template, including compute and networking configuration, can be consumed by another template as a single TOSCA node.