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dmenardSABA_235's avatar
dmenardSABA_235
Icon for Nimbostratus rankNimbostratus
Aug 25, 2011

Irule for redirect when all pool members down, need one for each pool? and what is the standard practice for sorry server?

This is what I have for an iRule to implement when all members of a pool are not available due to maintenance or unplanned outage 

when HTTP_REQUEST { if { [active_members EXAMPLETEST_POOL] == 0 } { HTTP::redirect "http://209.196.27.42/" } }

Now this is for one pool, we have over 10 pools. Is there a way to re-write this so the same iRule can be applied to each virtual server? Or do I need to create a separate iRule for each pool?

Lastly, the re-direct is going to one server serving the web page. This has to be mapped to a public IP at the firewall with the non-nat'd IP as the virtual server for that web server. Then a DNS record created for that public IP address.

Is this the typical practice for a sorry server? Are there any steps I can take to mitigate any risks if any in my present setup?

Thanks,

application delivery
dev
devops
iRules

20 Replies

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  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Aug 25, 2011
    You can use [LB::server pool] to get the currently selected pool instead of hardcoding it in the iRule. Your network config for the sorry VS seems standard.

     

     

    Aaron
  • dmenardSABA_235's avatar
    dmenardSABA_235
    Icon for Nimbostratus rankNimbostratus
    Aug 25, 2011
    Aaron,

     

     

    thanks, so you are saying instead of [active_members ] you would use [active_members LB:::server pool]?
  • Michael_Yates's avatar
    Michael_Yates
    Icon for Nimbostratus rankNimbostratus
    Aug 25, 2011
    Hi dmenardSABA,

     

     

    I think that what Hoolio is saying is that you don't have to hard code the pool name in the iRule. If you use [LB::server pool] that it will use the default pool assigned to the Virtual Server.

     

     

     
when HTTP_REQUEST {
if { [active_members [LB::server pool]] == 0 } {
HTTP::redirect "http://209.196.27.42/"
}
}
  • dmenardSABA_235's avatar
    dmenardSABA_235
    Icon for Nimbostratus rankNimbostratus
    Aug 25, 2011
    Thanks to you both. I'll give that a try with that change. Regarding the standard practice for a sorry server I am still open to knowing what other are doing?

     

     

    Thanks again,

     

     

    Dave
  • Michael_Yates's avatar
    Michael_Yates
    Icon for Nimbostratus rankNimbostratus
    Aug 25, 2011
    I would say that there is no best practice. There is only "what best fits your situation".

    I use a combination of redirects for custom content vanity splash and sorry pages and iRules.

    Here is a basic example: 

    
when HTTP_RESPONSE {
HTTP::respond 200 content "Site unavailable



System Maintenance
NOTICE: This site is down for maintenance.
"
}
  • Techgeeeg's avatar
    Techgeeeg
    Icon for Nimbostratus rankNimbostratus
    Jan 26, 2013
    Hi Everyone,

    I had a similar requirement of iRule as the one written here... Michael I need to know one thing from you... how can I merge the irule...

    when HTTP_REQUEST {

    if { [active_members [LB::server pool]] == 0 } {

    HTTP::redirect "http://209.196.27.42/"

    }

    }

    With this....

    when HTTP_RESPONSE {

    HTTP::respond 200 content "Site unavailable

    System Maintenance NOTICE: This site is down for maintenance.

    "

    }

    when HTTP_REQUEST {

    if { [active_members [LB::server pool]] == 0 } {

    HTTP::redirect "http://209.196.27.42/"

    }

    }when HTTP_REQUEST {

    if { [active_members [LB::server pool]] == 0 } {

    HTTP::redirect "http://209.196.27.42/"

    }

    }

  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    Jan 26, 2013
    how can I merge the irule... what action do you want to take when pool is down? is it redirection to http://209.196.27.42/ or responding maintenance page??
  • Techgeeeg's avatar
    Techgeeeg
    Icon for Nimbostratus rankNimbostratus
    Jun 13, 2013
    Hi Nitas,

     

    It's been some time I was not able to get back due to some issues .... well getting back to the topic.... what I need to do is when the first part has checked that all the pool members are down then I simply want to display a message that the Site is down for maintenance how can i achieve this.

     

     

    Regards,
  • Techgeeeg's avatar
    Techgeeeg
    Icon for Nimbostratus rankNimbostratus
    Jun 13, 2013
    Hi Nitas,

     

    It's been some time I was not able to get back due to some issues .... well getting back to the topic.... what I need to do is when the first part has checked that all the pool members are down then I simply want to display a message that the Site is down for maintenance how can i achieve this.

     

     

    Regards,
  • Kevin_Davies_40's avatar
    Kevin_Davies_40
    Icon for Nacreous rankNacreous
    Jun 13, 2013
    when HTTP_REQUEST {  
    if { [active_members [LB::server pool]] == 0 } { 
        HTTP::respond 200 content "  

             

        " 
    } 
 }