Forum Discussion
NimbostratusECV Health Monitor issue
We have BIGIP LTM 2000v for load Balancing Oracle WMS application.we have an issue with ECV health monitor configured in Pool. Detailed Problem Description:-
There are 3 real servers are accessible by below URLS
1.http://lmrydwmsap1.riydah.cpksa.local:7778/forms/frmservlet?config=wmshcrdc-hh 2.http://lmrydwmsap2.riydah.cpksa.local:7778/forms/frmservlet?config=wmshcrdc-hh 3.http://lmrydwmsap3.riydah.cpksa.local:7778/forms/frmservlet?config=wmshcrdc-hh
We have configured a Pool where these three real servers are added as pool member . we had configured ECV HTTP health Monitor to monitor these pool members i.e. the real servers
The details of health monitor are as below:-
Monitor Type :- HTTP Interval :- 5 Send String :- GET /forms/frmservlet?config=wmshcrdc-hh HTTP/1.1\r\nHost:\r\nConnection: close\r\n\r\n Receive String :- 200 OK . Service port :- 7778
Now the issue is when these real servers URL are down( Real server IPs are rechable from BIG IP but the Real server URLS are not accessible still the Pool members are showing healthy ( i.e. up ) .
We are not sure whether ECV health monitors are configured correctly and it is affecting our production .
Can anybody help on that .
Regds...Indrajit
5 Replies
What_Lies_Bene1Cirrostratus
You don't seem to have specified a host value in your send string?
Indrajit_Basak_Hi , here we have three real servers so what is the best practice . Shall we need to create three Health Monitor and associate specific host value health value in each health monitor . And add all three health monitor in Pool Configuration . For example :-
health Monitor 1 :- Send string GET /forms/frmservlet?config=wmshcrdc-hh HTTP/1.1\r\nHost:lmrydwmsap1.riydah.cpksa.local \r\nConnection: close\r\n\r\n
Health Monitor 2 :- Send String GET /forms/frmservlet?config=wmshcrdc-hh HTTP/1.1\r\nHost:lmrydwmsap2.riydah.cpksa.local \r\nConnection: close\r\n\r\n
Health Monitor 3 :- Send String GET /forms/frmservlet?config=wmshcrdc-hh HTTP/1.1\r\nHost:lmrydwmsap3.riydah.cpksa.local \r\nConnection: close\r\n\r\n.
Can you pls suggest best possible solution in our case ......
- nitass
Employee
Shall we need to create three Health Monitor and associate specific host value health value in each health monitor.
i understand it depends on how web server is configured. blank host header value (Host: ) or virtual server's FQDN may also work.
Now the issue is when these real servers URL are down( Real server IPs are rechable from BIG IP but the Real server URLS are not accessible still the Pool members are showing healthy ( i.e. up ).
do you have tcpdump when the issue was happening?
Troubleshooting Ltm Monitors by Aaron
https://devcentral.f5.com/wiki/advdesignconfig.TroubleshootingLtmMonitors.ashx The Lack of a Host header is certainly a problem. If there are multiple web sites hosted on the same servers accessible via different hostnames, then your monitor might be monitoring the default sites on those servers rather than the one you think you are monitoring.
If all three servers require different hostnames, I don't see how you could construct a single HTTP monitor to handle all three of them.
If you are putting your web servers behind a load balancer, you should configure them all to serve the same domain name.
JGCumulonimbus
The lack of a Host header may not be a problem, since you don't have that header under HTTP 1.0 anyway -- at least under HTTP 0.9, as I recall.
The simplest way is to configure one default HTTP server at all the backend application servers, making it accept all queries, whether there is a Host header or not, or whatever the value of the header might be.
