Forum Discussion
NimbostratusF5 - Sharepoint App Pool down does not load balancing
F5 is our loadbalancer for 2 SharePoint WFE's. When on Server Nr. 1 the App Pool is stopped then F5 balances the traffic to Server Nr. 2. If the App Pool on Server Nr. 2 is stopped then F5 is not redirecting the traffice to Server Nr. 1. What could be the reason for that? The Monitor on F5 shows allways a green Status on both testcases.
12 Replies
KevinA_246454Cirrostratus
HI
I have not seen your configuration but basically you mentioned that when you stop your App Pool the monitor stays green or in an avialble state.
With that said the F5 will still load balance to server where the app pool has stopped because your monitor is reporting the pool member is available. Please check your monitor configuration you have applied to the pool. Please post your configuration if you still have issues.
tmsh ltm list virtual "virtual server name"
tmsh ltm list pool "name of pool which is configured with the above virtual server"
Heinrich12_3671Hello
It is a TCP-Probe on the Port. The strange thing the load balancer stays green. The testcase is:
Stopp AppPool on Server 1 / AppPool on Server 2 is running -> F5 switches and Website is displayed
Stopp AppPool on Server 2 / AppPool on Server 1 is running -> F5 does not switch and Website is Not displayed
Actually the behaviour should be the same on both testcases.
Greetings
Heinrich- KevinA_246454
load balancing behaviors will be based on your health monitor, in a very basic configuration the f5 will load balance a connection to pool member as long as the pool member has a green status/available, Do you mind posting your configuration, not 100% but I would assume the default settings in the tcp monitor will check the port if its up and running. You will need to more then a simple port monitor to check your application status on the web server.
Best to ask your web team to create a test page for you, that contains a simple sting such as SERVER_UP, then create a custom http monitor to request the page with a recv string. Below is an example
ltm monitor http custom-monitorhttp { adaptive disabled defaults-from http destination : interval 5 ip-dscp 0 recv SERVER_UP recv-disable none send "GET /HealthCheck.html\r\n" time-until-up 0 timeout 16
[root@bipipbrplab01:Active:Disconnected] config curl --get http://10.1.2.12/HealthCheck.html
F5 Test PageSERVER_UP
The web server software is running.
[root@bipipb01:Active:Disconnected] config
- Heinrich12_3671
Hello Hier the output
ltm virtual CM-CH-PRD-APPNAME-STAGE-443 {
description CM-CH-PRD-APPNAME-STAGE-443
destination 10.123.123.123%2:https
ip-protocol tcp
mask 255.255.255.255
partition T3-ZZ02-F5S01
persist {
source_addr_3m {
default yes
}
}
pool SF01-CH-PRD-APPNAME-STAGE-443
profiles {
/Common/tcp { }
}
source 0.0.0.0/0
source-address-translation {
pool vlan_1265_8
type snat
}
translate-address enabled
translate-port enabled
vlans {
T3-CH02-VL1220
T3-CH02-VL1221
T3-CH02-VL1222
T3-CH02-VL1226
T3-CH02-VL1227
T3-CH02-VL1263
T3-CH02-VL1264
T3-CH02-VL1265
T3-CH02-VL1268
T3-CH02-VL74ltm pool SF01-CH-PRD-APPNAME-STAGE-443 {
members {
SERVER1:any {
address 10.123.83.125
session monitor-enabled
state up
}
SERVER2:any {
address 10.123.83.126
session monitor-enabled
state up
}
}
monitor PROBE-CH-ZZZ-APPNAME-STAGE-8082
partition T3-ZZ02-F5S01
- KevinA_246454
Hi Heinrich
Please see below, very good discussion on Sharepoint Monitor, I did say earlier ask your web administrator to create a health check page for you, configure your monitor to request the page and based on the response from the web server you can mark offline or online.
https://devcentral.f5.com/questions/sharepoint-health-monitors-59674
- Heinrich12_3671
Hi KevinA Thank you. I will try. Regards Heinrich
- Heinrich12_3671
Hi KevinA
2 weeks you asked me about the monitor configurationThanks the last thing we need to look at is the monitor configurations "tmsh ltm monitor "parent monitor" PROBE-CH-ZZZ-APPNAME-STAGE-8082
Here it is:
ltm monitor tcp PROBE-CH-ZZZ-APPNAME-STAGE-8082 {
adaptive disabled
adaptive-divergence-type relative
adaptive-divergence-value 25
adaptive-limit 200
adaptive-sampling-timespan 300
app-service none
defaults-from /Common/tcp
description none
destination *:us-cli
interval 10
ip-dscp 0
manual-resume disabled
partition T3-ZZ02-F5S01
recv none
recv-disable none
reverse disabled
send none
time-until-up 0
timeout 31
transparent disabled
up-interval 0
}Hope this helps
Regards
Heinrichxx - KevinA_246454
HI
 
Ok your monitor is a tcp monitor, here is a pretty good link explaining a tcp monitor https://devcentral.f5.com/s/articles/monitoring-tcp-applications-01
 
you can stop the app pool and see if you can open a connection to the web server if it responds then the tcp monitor will mark the server as green. If it does not respond when you open up a connection and the monitor is still marking the server as green, then it something we can look at.
 
I suggest you ask the web admin to setup a test page for you change your monitor to a https monitor if https is required, then configure a send string link I have posted earlier.
 
