deis
Custom "Site Maintenance" page
It'll be nice to be able to customise the blank "Site Maintenance" page, seen after deis maintenance:on.
Maybe a volume of static files can be mounted for nginx to read from. Not sure which volume type fits best?
A simpler implementation would be (optional) support for a designated "maintenance app" to which all traffic for an app under maintenance can be routed.
Heroku has a pretty simple solution of using config variables pointing to static page urls: https://devcenter.heroku.com/articles/error-pages#configure-your-application. So a user could set a config variable MAINTENANCE_PAGE_URL pointing to some static site to display.
From a cursory glance through the code base, this will require changes across multiple repos (there are probably more): controller, router model, router nginx config, workflow-cli
EDIT: Just realized Workflow is EOL... ☹️
