Forum Discussion

Peter_Reilly's avatar
Peter_Reilly
Icon for Nimbostratus rankNimbostratus
Jul 03, 2006

irule to detect if node is down

I'm trying to find an irule sample that does the following:

 

 

I have a pool with two nodes, and I only want node-b to be use if node-a is down.

 

 

I never want node-b to be used if node-a is up.

 

 

5 Replies

  • Hi preilly,

    Why not just use a "Priority" on the node?

    
    pool my_pool {
    lb_mode fastest
    min active members 1
    member 1.2.3.4:80 priority 2
    member 1.2.3.5:80 priority 1
    }

    This will mean that 1.2.3.4:80 will always be the "chosen" node, unless it is down, when 1.2.3.5:80 will be used...

    Check out the Config Guide for LTM "Specifying priority-based member activation".

    Cheers,

    - Derek.
  • Thanks, that looks promising, but I get an error as follows when I do a bigpipe merge:

     

     

    /config/bigip.conf: "syntax error" at character 'l' in line 399

     

    lb_mode fastest

     

     

    I'm using 9.0.4.

     

     

  • Which LB method is currently in use for this pool?

     

     

    You can use the one that's already applied.

     

     

    The trick here for your need (backup node) is really unsing prioritites for the Pool Members.

     

     

    Regards,

     

     

    -Rodrigo

     

     

  • I got past the error by using the gui to modify the pool.

     

     

    I have the following:

     

     

    pool TestAppHTTP {

     

    lb method fastest app resp

     

    min active members 1

     

    monitor all http

     

    member 172.17.244.2:7777

     

    member 172.17.245.21:http priority 2

     

    }

     

     

    However, it just round robins between each pool menber. I expected it to only select the menber set to priority 2, unless it was then down, and then select the other.

     

     

  • Seems to be a bug in 9.0.4.

     

     

    http://tech.f5.com/home/solutions/sol3983.html