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Luca_55898's avatar
Icon for Nimbostratus rankNimbostratus
Jun 25, 2011

Monitors not available at node level




I have 5 nodes in a pool, which i need to monitor for SMTP connectivity. These nodes do not reply to icmp or anything other than SMTP.



So i created a SMTP monitor, but noticed that the monitor is not available to assign to a node at the node level. I can only use the monitor on the pool.


The nodes were being marked down becase at the node level they were not responding to ICMP.


So i set the node level i set the monitor to None (since my SMTP one was not available) then made the node inherit the pool's monitor which was SMTP.



So in the node list they all get a little blue unknown square, but in the pool's node lise they are all green.



So is it normal for custom monitors not be to available at the node level?


And is the 'workaround' i did suitable to monitor the pool's nodes?





5 Replies

  • Hey guys,



    I ran into this same problem and figured out how to make the monitors work. When you setup the health monitor you need to make sure that you select advanced configuration and then under the alias port box you need to specify which port you want the monitor to check instead of using the default *all ports.


  • Hamish's avatar
    Icon for Cirrocumulus rankCirrocumulus
    What version of LTM?




    The docs are a bit vague on which monitors you can associate with nodes. Simply stating (9.2 docs, haven't gone back to check the later ones) that monitors explicitly designed to monitor pools or poolmembers aren't available to monitor nodes...



    I'm not sure which way it falls. I suspect it may be anything that monitors a port is pool level... And only IP level monitors are available to nodes... (Which pretty much means ICMP). Although tcp/echo is available for nodes I believe... But that won't help...



    Not sure about tcp and tcp/half-open... They'll probably just annoy whoever looks at your SMTP logs more than anything else. (If they even work at node level).



    You could perhaps try a custom (Scripted) monitor... Maybe theyre available 9Sorry for all the maybe's. I don't have access to an LTM where I am at the moment).






  • LTM version 10.2.1.


    We are running multiple route-domains as well.
  • Hi Luca,


    This monitor may not be avaliable on the Node level individually.... The gud reason is...if you have a server/node running more than one application/services and you assign SMTP monitor at the node level and if this SMTP service fails and the other service/application is running the box will mark this server as down similarly if the other service fails but SMTP is running then the server will be shown as up where as it has some problem.


    At the pool level we differentiate between the different services even if they are running on the same machine so that is why you see the avaliability of SMTP monitor. Monitors when applied at the Pool level will not effect the machine/server as a whole but only for a particular service. I hope you get this point.