need help with an irule

At the first look, you will not need an iRule for that. If I understand your scenario, you want to remove the load-balancing and high-availability for the DB service. As you described your scenario:

Can you specify what should happen if one of the DB servers fails? i.e DB1 comes unavailable, should the traffic from App Server 1 land in the DB2 server or is it not important?

yes that is how it should work

App server1 --- DB1 App server2----DB2

If either DB server fails then Ap1 and Ap2 should communicate to the other available database server.

Given the requirement to cover for High Availability despite strict IP-based routings, you're better off using an iRule.

I believe the code below covers your requirements.

Please give it a try and let me know if you have any questions. Replace the values of IP addresses, port numbers and the don't forget to modify the pool name "DB_servers_pool".

when CLIENT_ACCEPTED {


  if { [active_members DB_servers_pool] < 2}{
     Bypass the execution of strict IP-based routing. Allows F5 to select any node that is available
    return
  } elseif { [IP::client_addr] == "1.1.1.1" }{
     Explicitly forward App Server 1 traffic to a specific database pool member via TCP port 3306
    pool DB_servers_pool member 10.10.10.1 3306
  } elseif { [IP::client_addr] == "1.1.1.2" }{
     Explicitly forward App Server 2 traffic to a specific database pool member via TCP port 3306
    pool DB_servers_pool member 10.10.10.2 3306
  }

}

Regards,

doi need specify the port or can I get have the irule as below

when CLIENT_ACCEPTED {

if { [active_members DB_servers_pool] < 2}{ return } elseif { [IP::client_addr] == "1.1.1.1" }{ pool DB_servers_pool member 10.10.10.1 } elseif { [IP::client_addr] == "1.1.1.2" }{ pool DB_servers_pool member 10.10.10.2 }

}

and i more question if anyother source makes a connection to the database servers it should be based on the predictor and persistence correct .Only App1 and app2 traffic will be directed to the database servers based on the irule.

when CLIENT_ACCEPTED {

  if { [active_members DB_servers_pool] < 2 }{
    return
  } elseif { [IP::client_addr] == "1.1.1.1" }{
    persist none
    pool DB_servers_pool member 10.10.10.1
  } elseif { [IP::client_addr] == "1.1.1.2" }{
    persist none
    pool DB_servers_pool member 10.10.10.2
  }

}

Thanks a lot for your help ,finally I got this irule tested and its working . want to know if we need to enabled presistence rebalance where do i get this setup on http profile.