Forum Discussion

aalvino_578's avatar
aalvino_578
Icon for Nimbostratus rankNimbostratus
Jul 09, 2008

Failover, but not fail back

I am trying to do something that I thought would be fairly straight forward, but I cannot figure out how to do it.

 

 

I have a pool of 2 nodes which serve out an application. They cannot run in active/active mode, so they run primary/backup. Using the priority within the pool, I have things setup so that when the primary goes down, things properly start to go to the backup. The problem is that when the primary comes backup, it again starts to receive the reqeusts. I need the newly assigned (used to be backup) server to remain as the active one. I thought there would be a way using LB_STATUS within an iRule to change the priory of the members of the pool, but I cannot seem to find a way to do that. Does anyone know if there is a way within an iRule to change the priority of pool members?

 

 

application delivery
dev
devops
iRules

2 Replies

Sort By
  • hooleylist's avatar
    hooleylist
    Icon for Cirrostratus rankCirrostratus
    Jul 09, 2008
    I think this fits the bill nicely:

     

     

    Single Node Persistence

     

    http://devcentral.f5.com/wiki/default.aspx/iRules/SingleNodePersistence.html

     

     

    Aaron
  • aalvino_578's avatar
    aalvino_578
    Icon for Nimbostratus rankNimbostratus
    Aug 18, 2008
    Hello All,

     

     

    I am back.. sorry this sat so long, but I am having an issue with this. For some reason, the tcp connection goes down occasionally between the F5 and my application. This triggers the other node to now recieve the requests. I know the connection should stay up, but it is going down, and really causing a problem. Is there anyway to get this to failover only if one of the monitors for the node triggers the node being marked down?

     

     

    The other problem that I am facing with this solution is that if for some reason a switchover does occur because the tcpconnection goes down, I don't get any notifications. I.e. there is no snmp event, or even anything in the ltm log to indicate that the switchover has occurred...

     

     

    Any other thoughts on this would be greatly appreciated!

     

     

    Thanks