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Jason_Hook_4092's avatar
Jason_Hook_4092
Icon for Nimbostratus rankNimbostratus
Mar 10, 2015

Select member from within two pools via 4th octet value in URI

The following iRule works well, but I'm in need of some expert help altering this to accept a number equal to the 4th octet of the member IP, looking at more than one pool.

 

https://devcentral.f5.com/wiki/iRules.Select_pool_member_based_on_HTTP_query_string_parameter.ashx

 

I'd like to put this one iRule on two VIPs (so it's more generic) and be able to select a member from 2 pools (the default of each VIP) from either VIP. So, pass in member=23 and look at 2 pools at the same time to find 192.168.1.23

 

This is to facilitate a test request for application support to a server in either the live pool (using the live VIP) or the 'dark' pool (but via the same live VIP). the LTM VIPs alternate based on GTM setting. Both VIPs/Pools are on the same LTM.

 

I'm ok with coding the two pool names, so merge the members from both pools to find the matching member/IP.

 

Any help would be appreciated!

 

application delivery
devops
iRules

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  • Brad_Parker's avatar
    Brad_Parker
    Icon for Cirrus rankCirrus
    Mar 10, 2015

    [getfield [LB::server addr] "." 4]
    would give you the 4th octet of a pool members IP. Not exactly sure what you are wanting to change in that iRule, but this snippet should get you started.

  • Jason_Hook_4092's avatar
    Jason_Hook_4092
    Icon for Nimbostratus rankNimbostratus
    Mar 10, 2015

    I'm wondering how to combine two pools worth of member lists (or look in each pool separately) to find the matching member IP (in the noted iRule, it does a lIndex to pick the member from a sorted list, not real sure how to best alter that part to search the list for content matching on the 4th octet)

     

    • Brad_Parker's avatar
      Brad_Parker
      Icon for Cirrus rankCirrus
      Mar 10, 2015
      why are you searching for a specific pool member? Why not just use the node command if you know the specific node you are trying to send traffic to? Big picture, what are you trying to accomplish?
    • Jason_Hook_4092's avatar
      Jason_Hook_4092
      Icon for Nimbostratus rankNimbostratus
      Mar 10, 2015
      call the website with a URI param to connect to a specific server in one of the two pools and set a session cookie to persist for the session...so support can troubleshoot a single server in either the live pool or 'dark' pool. I suppose putting the entire IP in the URI as the param would be ok, figured just the 4th octet would be easier to type in. This app is also mobile enhanced so less typing would be desirable.
  • nitass's avatar
    nitass
    Icon for Employee rankEmployee
    Mar 10, 2015

    is it something like this?

     configuration

[root@ve11c:Active:In Sync] config  tmsh list ltm virtual bar
ltm virtual bar {
    destination 172.28.24.10:80
    ip-protocol tcp
    mask 255.255.255.255
    pool foo
    profiles {
        http { }
        tcp { }
    }
    rules {
        qux
    }
    source 0.0.0.0/0
    source-address-translation {
        type automap
    }
    vs-index 9
}
[root@ve11c:Active:In Sync] config  tmsh list ltm pool foo
ltm pool foo {
    members {
        200.200.200.101:80 {
            address 200.200.200.101
        }
    }
}
[root@ve11c:Active:In Sync] config  tmsh list ltm pool foobar
ltm pool foobar {
    members {
        200.200.200.111:80 {
            address 200.200.200.111
        }
    }
}
[root@ve11c:Active:In Sync] config  tmsh list ltm rule qux
ltm rule qux {
    when RULE_INIT {
   List of pool name
  set static::poollist { foo foobar }
   Parameter name
  set static::uriparam "member"
}
when HTTP_REQUEST {
  set param [URI::query "?[HTTP::query]" $static::uriparam]
  if { $param ne "" } {
    foreach name $static::poollist {
      foreach mbr [active_members -list $name] {
        if { [lindex $mbr 0] ends_with $param } {
          log local0. "Param=$param Pool=$name Pool member=$mbr"
          pool $name members [lindex $mbr 0] [lindex $mbr 1]
          return
        }
      }
    }
  } else {
     No parameter
  }
}
}

 /var/log/ltm

[root@ve11c:Active:In Sync] config  tail -f /var/log/ltm
Mar 10 22:21:14 ve11c info tmm[15262]: Rule /Common/qux : Param=111 Pool=foobar Pool member=200.200.200.111 80
Mar 10 22:21:24 ve11c info tmm[15262]: Rule /Common/qux : Param=101 Pool=foo Pool member=200.200.200.101 80