F5 is not marking the pool member status as DOWN

Sarovani · ‎11-Jun-2020

Hi All ,

When the service on the member node 10.179.16.19 is DOWN, the F5 monitor is not marking the pool member status as offline .

When server team changes the receive string code to 503 from 200 from the server end , pool member is not marked as DOWN ,

We then tested it and decided to change the monitor string to "200 OK" from 200 on the F5 ,it than worked correctly .

Meaning when server team now changed the string to 503 , monitor on the F5 marked pool member down .

So what is the issue here ? What is the difference with string 200 and 200 OK ?

ltm pool gw-internet-test_POOL {

description gw-internet-test

members {

10.179.16.19%6:https {

address 10.179.16.19%6

session user-disabled --------------> Manually disabled

state user-down

}

10.179.18.12%6:https {

address 10.179.18.12%6

session monitor-enabled

state up

}

monitor gw-internet-test_Monitor

partition CORP

ltm monitor https gw-internet-test_Monitor {

adaptive disabled

cipherlist DEFAULT:+SHA:+3DES:+kEDH

compatibility enabled

defaults-from /Common/https

destination *:*

interval 5

ip-dscp 0

partition CACF

recv 200 >>>>>>>>>>>>>>>>>>>>>>>> When we changed the string to "200 OK" , it worked

recv-disable none

send "GET /test/admin/login.jsp HTTP/1.1\r\nHost:gw-internet-test.corp.com"

time-until-up 0

timeout 16

}

cjunior · ‎16-Jun-2020

Hello,

Probably the string "200" appears on head or body, while the string "200 OK" appears only on http response code status in headers.

e.g.

This output has "200 OK" on header and "200" on body.

# curl -kv http://172.30.0.1/default.asp
*   Trying 172.30.0.1...
* Connected to 172.30.0.1 (172.30.0.1) port 80 (#0)
> GET /default.asp HTTP/1.1
> Host: 172.30.0.1
> User-Agent: curl/7.47.1
> Accept: */*
>
< HTTP/1.1 200 OK
< Cache-Control: private
< Content-Type: text/html
< Server: Microsoft-IIS/10.0
< Set-Cookie: ASPSESSIONIDCADABDAD=OPKBINHAKLGGIGHNPBCBEDGP; path=/
< Date: Tue, 16 Jun 2020 17:04:22 GMT
< Content-Length: 118
<
<html>
<head>
</head>
<body>
 200  is a number that matches 200
 2002 is a number that matches 200 as well
 </body>
</html>
* Connection #0 to host 172.30.0.1 left intact

This other response header example, the HTTP code is 503 while content-length is 200 that matches your recv param.

HTTP/1.1 503 Service Unavailable
Cache-Control: private
Content-Type: text/html
Content-Length: 200

Regards.

View solution in original post

Sarovani · ‎12-Jun-2020

Can anyone help here please ....

cjunior · ‎12-Jun-2020

Hello,

That status means that you forced offline a member.

If you need to grab availability from members, you can run 'show" instead of "list" command:

Also, you can have this output in field format as well:

show ltm pool gw-internet-test_POOL members field-fmt

Look for "status.availability-state" field for each member and you will get member's availability.

For a monitor status result, there is a little difference when you disable or force offline a member, where this is "down" when monitor failed and "user-down" when forced offline.

I hope it helps

cjunior

Sarovani · ‎16-Jun-2020

Hi Cjunior ,

Thanks for your response .

Sorry I have corrected my question ,

Issue reported : When the service on the member node 10.179.16.19 is DOWN, the F5 monitor is not marking the pool member status as offline .

When server team changes the receive string code to 503 from 200 from the server end , pool member is not marked as DOWN ,

Action taken : We decided to change the monitor string to "200 OK" from 200 on the F5 ,it than worked correctly .

Meaning when server team now changed the string to 503 , monitor on the F5 marked pool member down .

So what is the issue here ? What is the difference with string 200 and "200 OK"

cjunior · ‎16-Jun-2020

Hello,

Probably the string "200" appears on head or body, while the string "200 OK" appears only on http response code status in headers.

e.g.

This output has "200 OK" on header and "200" on body.

# curl -kv http://172.30.0.1/default.asp
*   Trying 172.30.0.1...
* Connected to 172.30.0.1 (172.30.0.1) port 80 (#0)
> GET /default.asp HTTP/1.1
> Host: 172.30.0.1
> User-Agent: curl/7.47.1
> Accept: */*
>
< HTTP/1.1 200 OK
< Cache-Control: private
< Content-Type: text/html
< Server: Microsoft-IIS/10.0
< Set-Cookie: ASPSESSIONIDCADABDAD=OPKBINHAKLGGIGHNPBCBEDGP; path=/
< Date: Tue, 16 Jun 2020 17:04:22 GMT
< Content-Length: 118
<
<html>
<head>
</head>
<body>
 200  is a number that matches 200
 2002 is a number that matches 200 as well
 </body>
</html>
* Connection #0 to host 172.30.0.1 left intact

This other response header example, the HTTP code is 503 while content-length is 200 that matches your recv param.

HTTP/1.1 503 Service Unavailable
Cache-Control: private
Content-Type: text/html
Content-Length: 200

Regards.

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F5 is not marking the pool member status as DOWN

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