F5 iRule – Serving Sorry Image

There are 3 steps to creating the F5 iRule to serve the image of a sorry page. Serving image of sorry page is utilized when you need to serve non-English characters which may not be compatible with F5. Of course, you can use it even for simple sorry pages with English characters.

There are 3 main steps:

• Create a base64 image of the original Sorry Page Image
• Create a datagroup that references the base64 Sorry Page Image
• Create an iRule that reference the datagroup and attach this to the Virtual Server that requires the Sorry Page iRule.

Create a base64 image of the original Sorry Page Image:

1. Copy the image (SORRY_IMAGE.png – this should be less than 46KB in size) onto F5’s directory /var/tmp/SORRY_IMAGE.png
2. The following command should be copied to the F5 shell as a single line in order to create the base64 image
   echo \"SORRYIMAGE\" \:\= \"`base64 /var/tmp/SORRY_IMAGE.png | xargs echo | sed 's/ //g'`\"\, > /var/class/SORRY.class
3. Check /var/class/SORRY.class
   [root@f5-ltm:Active] config # head /var/class/SORRY.class
"SORRYIMAGE" := "iVBORw0KGgoAAAANSUhEUgAABAAAAAMACAMAAACNZOU/A ...... <<remaining output omitted>>

Create a datagroup that references the base64 Sorry Page Image via GUI:

when HTTP_REQUEST {
  if { ([active_members [LB::server pool]] < 1)} {
      HTTP::respond 503 content [b64decode [class element -value 0 SORRY_PAGE]]
      event disable
     }
}