The scratch environment (http://core-functional.ci.folio.org/) is a shared environment for deploying and testing back-end modules. Back-end devs can use it in place of the local Okapi setups described in this document: https://dev.folio.org/guides/run-local-folio/, which eliminates a lot of the work of setting up a local development environment. No fiddling with virtualboxes, local host networks, or the Okapi module registration process necessary.
What is Rancher?
From the Rancher site: Rancher is an open source software platform that enables organizations to run and manage Docker and Kubernetes in production. With Rancher, organizations no longer have to build a container services platform from scratch using a distinct set of open source technologies. Rancher supplies the entire software stack needed to manage containers in production.
To put it another way, Rancher is a tool for deploying Docker containers to the scratch environment quickly and relatively painlessly. You can overwrite the stock docker container for a given module with your own and be testing it on the scratch environment in minutes.
Requirements:
Docker will need to be installed on your system, and you will need to set up a public docker repo in docker hub. Working with back-end modules also requires Maven and a recent version of the Java SE.
How to do it:
Clone the module you need to work on from github using the --recursive flag.
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...make sure that you go back to the upgrade screen for that module in Rancher and remove the new answer fields you added, then hit the upgrade button. This should clear your image from the scratch environment.
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