Here is my requirement.
a) user tries opening the signin.html that will be used to log in to the application
b) if the webserver or app server is down at this time, instead of showing the signin.html,
user should be taken to a maintenance.html ( Maintenance.html page will have more descriptive
text for the user to read)
c) Send email to the application DBA when (b) is true saying that the web/app server is/are down.