NimbostratusI am trying to use Dynamic Ratio Load Balancing based upon CPU thresholds learned via the WMI monitor. However, all the documentation I've seen only gives you the instructions on installing it for IIS, not Apache.. Although, from what I've read it sounds like it will run on any Windows Server running WMI.
NimbostratusThis answer may be a bit stale by now, but here goes...
Although Windows servers will have the WMI available (if installed), the required plugin is designed for IIS. The plugin will perform the WMI queries and return a formatted (XML I believe) response to the F5.
So, in theory, it could be possible to roll your own WMI interface for anything, such as Tomcat, as long as it accepted the same POST requests and spit out the equivalent XML.
You're probably better off using SNMP though. I just opened and sadly closed a support ticket with F5 regarding problems with the WMI plugin (the F5.IsHandler.dll for IIS 7+ servers). It fails to return valid data on a Hyper-V virtual machine with the latest version of that DLL (1.0.5). Older versions of that DLL (1.0.4) will report data back, but only the first CPU. Plus, even on a physical system, it only reports the actual physical CPU cores, but not any hyper-threaded cores.
If all your systems are identical, not a big deal, but if you have a mix, then systems with a lot of CPU's (virtual or hyperthreaded) might not get reported correctly, throwing off the metrics.
I think it boils down to the WMI queries they're using being a little too generic. I asked if they would just release the source code for that DLL but I won't hold my breath. Seems like an easy task to just fix the WMI query so it pulls the correct info, but then it would need to be regression tested and so on.
So yeah, I'll be using SNMP even though I've been using WMI for a while.