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mlick2's avatar
mlick2
Icon for Nimbostratus rankNimbostratus
Mar 17, 2006

Downtime redirect

I am trying to figure out the best way to redirect an application when it is determined to be down. This unfortunately has to be a manual process in determining if the app is down or not. What we would like to do is have the load balancer look for a file on a web server that will be put in place when we consider the app down, and when it sees that page up, it will direct users to that web site rather than the actual application pool. Can someone please lead me in the right direction. I would expect that I need an I-Rule for that virtual server stating something such as:

 

 

Example:

 

Use poolA (app down page) if true

 

else

 

Use poolB (normal appliction)

 

 

Please let me know if you need additional information.

 

 

Thanks in advance for your assistance.
application delivery
dev
devops
iRules
  • JRahm's avatar
    JRahm
    Icon for Admin rankAdmin
    Mar 17, 2006
    actually, that can be done without rules. You can create a custom monitor to look for the page, and mark the pool member down if present. Redirection can be done without rules by setting a fallback host that will kick in when all pool members are down.
  • mlick2's avatar
    mlick2
    Icon for Nimbostratus rankNimbostratus
    Mar 17, 2006
    Thank you for the quick response. Fallback host will work for us when all the hosts are down. But we also want to be able to redirect while the pool is still up when it is deteremined that the back end application is down.
  • JRahm's avatar
    JRahm
    Icon for Admin rankAdmin
    Mar 17, 2006
    Ok, sorry, misunderstood. Is the middleman a webserver? If so, you can use a reverse http monitor that is UP while the condition is NOT met. Configure the action on service down to reselect and you should be fine.

    
monitor my_http {
   defaults from http
   reverse
   recv "APPLICATION IS DOWN!"
   send "GET /yourpath/yourfile.txt"
}

    Note that the send is the file that is there only when the app is down, and the recv is a string in the file that can be matched appropriately.