I am trying to use the 'when LB_FAILED' to send requests a pool just for apologies. The issue is that the requests coming into the VS have crazy long URI strings like '/ABC/def/g/hij/klmno/' and my sorry server is running a simple HTML page at '/apologies/apologies.htm' I have configured this directory and page to be the default, so I can hit the server directly at 'http://host.domain.com/' and get the correct content. I have tried a few different variations, and can't seem to be able to change the URI after 'when LB_FAILED' before the request goes to the apologies pool. Rev 1, I added some logging to see what was being passed when LB_FAILED { log local0. "URI is [HTTP::uri]" log local0. "$poolname has [active_members [LB::server pool]] members" log local0. "URI is [HTTP::uri]" pool pool_apologies_http log local0. "Directed to pool [LB::server pool]" } Rev 2, tied the HTTP::uri command when LB_FAILED { log local0. "URI is [HTTP::uri]" log local0. "$poolname has [active_members [LB::server pool]] members" HTTP::uri "/" log local0. "URI is [HTTP::uri]" pool pool_apologies_http log local0. "Directed to pool [LB::server pool]" } Can I do this with the 'when LB_FAILED' command, or does it have to be HTTP_REQUEST?? Thanks, -L

Hi lsouth, You can force a reselect from a new pool using LB::reselect pool $my_pool, but it gets more complicated if you want to serve multiple files (like html and images) from that pool: Maintenance Page iRule (Click here) If you do need to support multiple objects for the maintenance page, you could not rewrite the URI if the Referer header ends with the maintenance page. I haven't test any of this, but at least the HTTP::uri update was working for DJ-Boston. Aaron

Changing to LB::reselect works, but I am having the same issue as DJ-Boston, no images....

Here is the rule with mods for my environment when LB_FAILED { log local0. "[IP::client_addr]:[TCP::client_port]: Request to pool failed, [LB::server pool]" Check if this request was not generated from the maintenance page using the HTTP referer header if {not ([HTTP::header value referer] ends_with "/apologies.htm")}{ log local0. "[IP::client_addr]:[TCP::client_port]: Referer wasn't the maintenance page. Rewriting URI to maintenance page." HTTP::uri "/" } Send request to the apologies pool LB::reselect pool pool_apologies_http log local0 "[IP::client_addr]:[TCP::client_port]: Reselecting member from the apologies pool" } and here are my logs Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page. 01220001:3: TCL error: Rule rule_apologies_http-referrer - wrong args: should be "log" Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page. 01220001:3: TCL error: Rule rule_apologies_http-referrer - wrong args: should be "log" Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page. 01220001:3: TCL error: Rule rule_apologies_http-referrer - wrong args: should be "log" Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page. 01220001:3: TCL error: Rule rule_apologies_http-referrer - wrong args: should be "log" Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page. 01220001:3: TCL error: Rule rule_apologies_http-referrer - wrong args: should be "log" Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page. Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page. Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page. Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page. Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page. Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page. Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page. Rule rule_apologies_http-referrer : 10.20.45.9:2758: Request to pool failed, pool_prod Rule rule_apologies_http-referrer : 10.20.45.9:2758: Referer wasn't the maintenance page. 01220001: repeated 8 times

Using LB_FAILED and change the URI w/o 302

hooleylist
Cirrostratus
Oct 17, 2008
Hi lsouth,

You can force a reselect from a new pool using LB::reselect pool $my_pool, but it gets more complicated if you want to serve multiple files (like html and images) from that pool:

Maintenance Page iRule (Click here)

If you do need to support multiple objects for the maintenance page, you could not rewrite the URI if the Referer header ends with the maintenance page.

I haven't test any of this, but at least the HTTP::uri update was working for DJ-Boston.

Aaron
Leslie_South_55
Nimbostratus
Oct 20, 2008
Changing to LB::reselect works, but I am having the same issue as DJ-Boston, no images....

hooleylist

Cirrostratus

Oct 20, 2008

Can you try this then? I assume HTTP::referer should work in LB_FAILED if HTTP::uri does, but haven't tested this before.

 
 when LB_FAILED { 
  
    log local0. "[IP::client_addr]:[TCP::client_port]: Request to pool failed, [LB::server pool]" 
  
     Check if this request was not generated from the maintenance page using the HTTP referer header 
    if {not ([HTTP::header value referer] ends_with "/maintenance_page.html")}{ 
  
       log local0. "[IP::client_addr]:[TCP::client_port]: Referer wasn't the maintenance page.  Rewriting URI to maintenance page." 
       HTTP::uri "/maintenance_page.html" 
    } 
  
     Send request to the apologies pool 
    LB::reselect pool pool_apologies_http 
    log local0. "[IP::client_addr]:[TCP::client_port]: Reselecting member from the apologies pool" 
 }

Aaron

Leslie_South_55
Nimbostratus
Oct 20, 2008
Here is the rule with mods for my environment

when LB_FAILED { log local0. "[IP::client_addr]:[TCP::client_port]: Request to pool failed, [LB::server pool]" Check if this request was not generated from the maintenance page using the HTTP referer header if {not ([HTTP::header value referer] ends_with "/apologies.htm")}{ log local0. "[IP::client_addr]:[TCP::client_port]: Referer wasn't the maintenance page. Rewriting URI to maintenance page." HTTP::uri "/" } Send request to the apologies pool LB::reselect pool pool_apologies_http log local0 "[IP::client_addr]:[TCP::client_port]: Reselecting member from the apologies pool" }

and here are my logs

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page.

01220001:3: TCL error: Rule rule_apologies_http-referrer - wrong args: should be "log"

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page.

01220001:3: TCL error: Rule rule_apologies_http-referrer - wrong args: should be "log"

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page.

01220001:3: TCL error: Rule rule_apologies_http-referrer - wrong args: should be "log"

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page.

01220001:3: TCL error: Rule rule_apologies_http-referrer - wrong args: should be "log"

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page.

01220001:3: TCL error: Rule rule_apologies_http-referrer - wrong args: should be "log"

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page.

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page.

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page.

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page.

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2756: Referer wasn't the maintenance page.

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page.

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2757: Referer wasn't the maintenance page.

Rule rule_apologies_http-referrer : 10.20.45.9:2758: Request to pool failed, pool_prod

Rule rule_apologies_http-referrer : 10.20.45.9:2758: Referer wasn't the maintenance page.

01220001: repeated 8 times
Leslie_South_55
Nimbostratus
Oct 20, 2008
no images yet
Leslie_South_55
Nimbostratus
Oct 20, 2008
I also checked the HTTP headers and I am not seeing a referrer, but I am seeing

Content-Location: http://host.domain.com/apologeis.htm

-L

hooleylist

Cirrostratus

Oct 21, 2008

In order to work, the URI you check for in the Referer header and what you set the URI should be the same value in both places in the rule. And it should be different from normal pages that a user would request (so not something like "/" or "index.htm"). Can you test by renaming the maintenance page on the sorry pool server to something like /maintenanace.htm and use the rule below with more logging?

Also, there was an error in your example from a missing period in the syslog facility (log local "...") which generated the TCL error in the logs.

 
  when LB_FAILED {  
    
     log local0. "[IP::client_addr]:[TCP::client_port]: Request for [HTTP::uri] from [HTTP::header Referer] to pool failed, [LB::server pool]"  
    
      Check if this request was not generated from the maintenance page using the HTTP referer header  
     if {not ([HTTP::header value referer] ends_with "/maintenance.htm")}{  
    
        log local0. "[IP::client_addr]:[TCP::client_port]: Referer wasn't the maintenance page.  Rewriting URI to maintenance page."  
        HTTP::uri "/maintenance.htm"  
     } 
    
      Send request to the apologies pool  
     LB::reselect pool pool_apologies_http  
     log local0. "[IP::client_addr]:[TCP::client_port]: Reselecting member from the apologies pool"  
  }

Aaron

Leslie_South_55
Nimbostratus
Oct 21, 2008
Sorry about the type-o in the log statement..I have renamed the site to maintenance.htm and it has an associated maintenance_files folder for all the "stuff" (images, css, js) I see now that the request is for my full app path "/Library/controller/e/web/Portal/en/maintenance_files/c.gif" for all the images, etc. ideally we would want "/maintenance_files/c.gif"..any way around this that you can think of? The maintenance page is provided by our customer, so we can't really change the content, hence all the JS and CSS files.

: 10.20.45.9:4741: Request for /Library/controller/e/web/Portal/en/Customer:Enter from to pool failed, pool_prod

: 10.20.45.9:4741: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4741: Reselecting member from the apologies pool

: 10.20.45.9:4741: Request for /Library/controller/e/web/Portal/en/maintenance_files/main.css from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4741: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4741: Reselecting member from the apologies pool

: 10.20.45.9:4742: Request for /Library/controller/e/web/Portal/en/maintenance_files/screen.css from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4742: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4742: Reselecting member from the apologies pool

: 10.20.45.9:4741: Request for /Library/controller/e/web/Portal/en/maintenance_files/table.css from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4741: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4741: Reselecting member from the apologies pool

: 10.20.45.9:4742: Request for /Library/controller/e/web/Portal/en/maintenance_files/print.css from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4742: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4742: Reselecting member from the apologies pool

: 10.20.45.9:4741: Request for /Library/controller/e/web/Portal/en/maintenance_files/detection.js from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4741: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4741: Reselecting member from the apologies pool

: 10.20.45.9:4742: Request for /Library/controller/e/web/Portal/en/maintenance_files/dropdown.js from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4742: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4742: Reselecting member from the apologies pool

: 10.20.45.9:4741: Request for /Library/controller/e/web/Portal/en/maintenance_files/c.gif from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4741: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4741: Reselecting member from the apologies pool

: 10.20.45.9:4742: Request for /Library/controller/e/web/Portal/en/maintenance_files/mast-logo.gif from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4742: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4742: Reselecting member from the apologies pool

: 10.20.45.9:4741: Request for /Library/controller/e/web/Portal/en/maintenance_files/image001.gif from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4741: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4741: Reselecting member from the apologies pool

: 10.20.45.9:4742: Request for /Library/controller/e/web/Portal/en/maintenance_files/pmh.js from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4742: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4742: Reselecting member from the apologies pool

: 10.20.45.9:4741: Request for /Library/controller/e/web/Portal/en/maintenance_files/left-nav-corner.gif from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4741: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4741: Reselecting member from the apologies pool

: 10.20.45.9:4742: Request for /Library/controller/e/web/Portal/en/maintenance_files/443.jpg from http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter to pool failed, pool_prod

: 10.20.45.9:4742: Referer wasn't the maintenance page. Rewriting URI to maintenance page.

: 10.20.45.9:4742: Reselecting member from the apologies pool

hooleylist

Cirrostratus

Oct 21, 2008

Of course... the client never knows about the maintenance URI as it's not being sent a redirect. So the Referer header value still shows the original URI it was making the request from. How about checking for the string "/maintenance_files/" in the requested URI and not rewriting those requests? Is it safe to assume that only the maintenance files will have that in the URI?

 
   when LB_FAILED {   
      
      log local0. "[IP::client_addr]:[TCP::client_port]: Request for [HTTP::uri] from Referer '[HTTP::header Referer]' to pool failed, [LB::server pool]"   
      
       Check if this request was not generated from the maintenance page using the HTTP referer header   
      if {not ([HTTP::path] contains "/maintenance_files/")}{   
      
         log local0. "[IP::client_addr]:[TCP::client_port]: Referer wasn't the maintenance page.  Rewriting URI to maintenance page."   
         HTTP::uri "/maintenance.htm"   
      }  
      
       Send request to the apologies pool   
      LB::reselect pool pool_apologies_http   
      log local0. "[IP::client_addr]:[TCP::client_port]: Reselecting member from the apologies pool"   
   }

Aaron

Leslie_South_55
Nimbostratus
Oct 22, 2008
Now I am getting 404's for all the images

GET /Library/controller/e/web/Portal/en/maintenance_files/maintenance_files/main.css HTTP/1.1

Accept: */*

Referer: http://host.domain.com/Library/controller/e/web/Portal/en/Customer:Enter

Accept-Language: en-us

Accept-Encoding: gzip, deflate

User-Agent: Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; InfoPath.1; .NET CLR 2.0.50727; MS-RTC LM 8)

Host: host.domain.com

Connection: Keep-Alive

Cookie: f5_cookie=369694218.20480.0000

HTTP/1.1 404 Not Found

Content-Length: 1635

Content-Type: text/html

Server: Microsoft-IIS/6.0

X-Powered-By: ASP.NET

Date: Wed, 22 Oct 2008 15:10:37 GMT

Connection: keep-alive

Set-Cookie: f5_cookie=369694218.20480.0000; path=/

Here is the log from the webserver, 10.22.9.22 is the server IP and 10.22.9.10 is the LTM's SNAT IP

2008-10-22 15:10:37 W3SVC1799446788 10.22.9.22 GET /Library/controller/e/web/Portal/en/maintenance_files/maintenance_files/main.css - 80 - 10.22.9.10 Mozilla/4.0+(compatible;+MSIE+6.0;+Windows+NT+5.1;+SV1;+InfoPath.1;+.NET+CLR+2.0.50727;+MS-RTC+LM+8) 404 0 64

This repeats for every request to the 'maintenance_files' objects.

-L

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