Forum Discussion
CirrusDynamic ratio calculation
Hi,
I would like to calculate ratio that would be assigned to pool members. The values that i want to use are displayed in a web (xml) health check page (those are indeed java instances health information). So i want to LB according the health of the Java instances. I suppose that an iRule can do the job, but my worry is that an iRule is only triggered when traffic is received, not like a monitor. So i'm wondering how this could probably work. :s
I have red about Dynamic ratio and snmp-dca monitor, in which, from my understanding, LB occurs according to snmp queries results, but i don't know if that could match my need.
Any help much welcome Thank you
3 Replies
- Kevin_Stewart
Employee
It sounds like you need to collect health information from web calls and then modify load balancing ratio accordingly. As you've discovered, the dynamic ratio mechanism relies on SNMP data, so you'll most likely need a custom script monitor that polls for the health check information, performs some ratio calculation, then modifies the ratio settings for each pool member.
Can you provide more information about what the health check data looks like?
- Kevin_Stewart
I understood you to say that the health information is available via an HTTP call. Does the application also support SNMP?
- Kevin_Stewart
If the servers support SNMP, then you have potentially three options:
- Use the built-in dynamic ratio monitor, described in detail here:
http://support.f5.com/kb/en-us/solutions/public/9000/100/sol9125.html?sr=32489745
- Use Kirk's advanced SNMP ratio script (which would need to be updated for v11):
https://devcentral.f5.com/wiki/advdesignconfig.SNMPDynamicRatioMonitor.ashx
- Or create a custom HTTP monitor script that polls the health information page and modifies pool member ratios based on aggregate data.
