VPN Server Capacity Monitor

VPN Server Capacity Monitor

I am new to the Linux world and am clueless how to go about accomplishing
this task. Any help is GREATLY appreciated.
The task is to monitor VPN servers and 1) provide a real-time VPN Status
Page showing % utilized for each server, and 2) provide management with
warnings when server capacity reaches a predefined threshold. I am looking
for something kind of like what the uptime command provides (# users and
average cpu utilization over the past 1 minute, 5 minutes, and 15 minutes)
only I need to know:
Number of VPN Users connected
Percent CPU utilization
Percent Memory utilization (over what's required when the server is idle)
Percent Bandwidth utilization
And then I need to boil these down to a single number for a status page.
I'm thinking the maximum percentage of the four metrics above for the 1
minute mark would be good for the status page. Thoughts?
Oh yeah. I also need to be able to extract these metrics remotely.
I am open to other metrics that might help me know when a server is
becoming overloaded.
Thanks in advance