We can leverage off a load balancing service that will automatically check to see if a server is up, and will fail back to the maintenance page if the server is not reachable. For example we can leverage of
One of such examples is Global Server Load Balancing hosted by Illinois. GSLB is a load balancing system that will respond to DNS queries and returns an IP address associated with the name. GSLB will continuously check the main IP address to see if this up and responding. Once it detects no response it will switch to the backup IP address. Once the main IP address is back up, GSLB will switch back to the regular IP address.
A discussion has started with the neteng team to see how we can support a system like this at NCSA. Examples being considered is a nginx high availability, keepalived, etc.
All files will be hosted in /home/maintenance/<server>, the following is what is recommended: