Using F5 as a fall back host

Yes, you can absolutely have multiple iRules reference a single event on one virtual server.

 

 

Colin

SO this logic should work - based on the trimmed down version without the image (for easier following):

when RULE_INIT {
  set polr "We are currently performing maintenance.  Please check back later."
}
when HTTP_REQUEST {
  if {[active_members Wildcard_Pool_Test] == 0} {
    HTTP::respond 200 content $::polr
  }
  elseif {[HTTP::cookie exists "cookieName"]} { 
        HTTP::cookie decrypt "cookieName" "passphrase" 
      }   
} 
  when HTTP_RESPONSE { 
      if {[HTTP::cookie exists "cookieName"]} { 
         HTTP::cookie encrypt "cookieName" "passphrase" 
      } 
  }

Excellent thanks, so I should just keep the cookie handling as a separate iRule...and put it behind the rule I have for checking if there aren't any nodes available?

The version you have listed should work fine. As there isn't any conflict between the two rules, you could also add them separately on the same VIP without any issues. The HTTP_RESPONSE event won't trigger if you're sending a response using HTTP::respond. And I don't think there is any issue with trying to decode the cookie even if you're sending a redirect. It's basically up to you as to which is easier to manage.

 

 

Aaron

Hello.

 

 

thx for the answer, i thought someting like that.

 

I still get an error when I try to insert the irule,

 

do i hav eto set the location in "HTTP::respond 301 "Location" "${::maint_prefix}/""

 

to the pool?

You can set the Location variable ::maint_prefix in the RULE_INIT event. I'm guessing the error you're seeing when trying to save the rule is because the example in the Codeshare post is exactly as it would appear in the bigip.conf. To save via the GUI, remove the rule definition "rule webserver {" and the last closing curly brace "}".

 

 

If you still get an error, can you reply with the error text?

 

 

Aaron

Hello,

 

but when I remove the whole webserver section, there is nothing left than the 2 class definition,

 

maybe I miss something here.

 

 

This is the error I get

 

01070151:3: Rule [offline_sites_redirect_2] error:

 

line 1: [undefined procedure: class] [class maint_index_html {

 

type string

 

filename "/var/class/maint.index.html.class"

 

...

If you're using the GUI or iRuler, here is the rule text you can paste in:

 
  when RULE_INIT { 
      
      maint_prefix must not contain a trailing slash 
      maint_prefix also must not exist on your real web servers 
      
     set maint_prefix "/maintenancepage" 
     set maint_len [string length $maint_prefix] 
   } 
   when HTTP_REQUEST { 
      
      Service requests for files (URIs) from the maintenance page 
      Note that we always service these pages, even if the http_pool is up 
      
     set uri [HTTP::uri] 
     if { $uri equals ${::maint_prefix} } { 
        HTTP::respond 301 "Location" "${::maint_prefix}/" 
        return 
     } 
     if { $uri starts_with "${::maint_prefix}/" } { 
         trim off the maintenance prefix 
        set uri [string range $uri $::maint_len end] 
  
         Return the requested page 
        switch $uri { 
          "/"              - 
          "/index.html"   { HTTP::respond 200 content [lindex $::maint_index_html 0]           "Content-Type" "text/html" } 
          "/logo.png"     { HTTP::respond 200 content [b64decode [lindex $::maint_logo_png 0]] "Content-Type" "image/png" } 
          default         { HTTP::respond 404 } 
        } 
        return 
     } 
  
      
      If the http_pool is down, redirect to the maintenance page 
      
     if { [active_members http_pool] < 1 } { 
       HTTP::redirect "${::maint_prefix}/index.html" 
       return 
     } 
   } 
 

The classes are defined separately in the GUI under Local Traffic >> iRules >> Datagroup List.

Aaron

That worked as listed in the Codeshare example on 9.4.4. Are you defining the external class as a type 'string'? Can you try manually editing the class file on the filesystem and escape the backslashes as listed below:

 
 class maint.index.html.class { 
    type string 
    filename "/var/class/maint.index.html.class" 
 } 
 

cat /var/class/main.index.html.class

 
 "Maintenance pageSorry! This site is down for maintenance.", 
 

And no, if you're redirecting the client the address bar will be updated with the new location. You can pick whatever URL by modifying the redirect location, but you can't hide the change with this type of implementation.

Aaron

in the conf is looks like this:

 

class maint_logo_png extern {

 

type string

 

filename "/var/class/maint.logo.png.class"

 

}

 

class maint_index_html extern {

 

type string

 

filename "/var/class/maint.index.html.class"

 

}

 

 

I liked the irule at the beginning of this thread,

 

 

when RULE_INIT {

 

set sorry "

All Servers Down

 

"

 

}

 

when HTTP_REQUEST {

 

if {[active_members myPool] == 0} {

 

HTTP::respond 200 content $::sorry

 

}

 

}

 

 

it did keep the original URL, so the visitor only sees the domain and no internal stuff.

 

Cant we insert a picture there?