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Corporal_Pike_1's avatar
Corporal_Pike_1
Icon for Nimbostratus rankNimbostratus
Feb 26, 2018

Monitor a non-pool member as additional status check?

Hi, Sorry if this has been asked many times but I cant find an answer yet on devcentral.

 

I have a simple round robin virtual server with two member servers, server 1 and server 2. I am checking each server status using a HTTPS monitor.

 

I also want to monitor the status of two completely different servers, servers 3 and 4 as servers 1 and 2 depend on them to operate.

 

How do I create a monitor that will check a different destination server that I can then bind to my original server so that it requires both its own monitor and this second server monitor to be up to be in service? I don’t want servers 3 or 4 to be pool members, but I want their status available as an extra check for servers 1 and 2?

 

Does this require an external monitor?

 

Thanks a lot!

 

application delivery
LTM

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  • nathe's avatar
    nathe
    Icon for Cirrocumulus rankCirrocumulus
    Feb 26, 2018

    Corporal Pike,

     

    To do this you will need to create two new monitors, one for server 3 and one for server 4. Create the monitor as you would normally but set the Alias Address to the IP address of server 3 for one monitor, and server 4 for the other.

     

    Then in your pool with server 1 and 2 you would need to configure the monitors on the individual pool members, rather than at the group level. For example, for server 1 add the existing HTTPS monitor and the monitor with Alias Address for server 3. Set the minimum available monitors to 2. That way both monitors need to come up to mark server 1 up. If server 3 went down it would mark down server 1 from the pool.

     

    Hope this helps,

     

    N

     

  • JRahm's avatar
    JRahm
    Icon for Admin rankAdmin
    Feb 27, 2018

    Is there a way to test through servers 1 and 2 to servers 3 and 4? In past employ, I had a test check page for dependent services so I knew that backend services were available to the tier I was delivering traffic to from the BIG-IP. What Nathan is suggesting is a solid way to go, but it does add complexity, especially at scale.

     

  • Corporal_Pike_1's avatar
    Corporal_Pike_1
    Icon for Nimbostratus rankNimbostratus
    Feb 27, 2018

    Great this is just what ive been looking for - i didnt realise Alias set a different target address.

     

    Thanks a lot!