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mabdrasol's avatar
mabdrasol
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May 26, 2019

LTM+GTM at same box

we have two LTM nodes at HA setup and we need to migrate External DNS to F5 GTM

LTM and GTM license at same node

 

but I cant find a clear steps to do that or the best practices.

 

  • Hi mabdrasol,

    it can be done, no problem on using LTM and GTM on the same box. In regards to best practices, I would suggest you create the DNS configuration on your GTM devices, create listener with an IP address different to the current one serving the DNS request. Test extensively via dig/lookups and only when you are sure all is good, you perform the cutover re-pointing the NS records to the GTM's listeners.

     

    Best Regards,

    Oscar Pucheta

    https://www.australtech.net

    https://www.linkedin.com/in/npucheta/

  • Hi Oscar,

    thanks for your replay

    I'm confused here in this implementations as my f5 has below interfaces

    -self IP (for LTM)

    -floating IP (for LTM)

    -HA IP

    when I try to add GTM and LTM as a servers do I need to add more self IPs for GTM as I cant use same self IP for GTM and LTM.

     

  • Hi, The selfip belongs to the device itself, it doesn't matter if you are using LTM or GTM, so, just add the device once, with the non-floating selfip and that's it. If you have LTM provisioned and you want to discover the Virtual Servers, then enable Virtual Server Discovery

  • if the devices are in HA, add both non-floating self-ips one for each device. But still add only once, so lets say the HA pair has these two devices:

    -ltm01

    -ltm02

     

    then add the HA pair with a name like this: ltm01-02 and use the non-floating self ip for each device. Important point is that even you have two devices, because they are in HA, you just add once.

    • AshrafKassem's avatar
      AshrafKassem
      Icon for Nimbostratus rankNimbostratus

      Hi,

      can you please, explain to me what you mean? I have same setup HA LTM working as Active/Standby and i will add GTM License to the box. 

      should I login to the active F5 and add Two servers with Self-IP (one for active and for standby)?

      should I do this step on active and standby F5?

      should i use the Synck group in GTM?

       

  • Hello Oscar,

    thanks for great tips.

    now I have added

    -F5 node with two self ips

    -create listener ip

    -create pool with existing LTM VS.

    -create wideip with a record for this pool.

    -use dig tool to test dns resolving using listening ip from internal lan and resolving worked fine.

    now I need to use this test from WAN side but I have a confusion here

    here is my design

    remote user >>WAN>>NET Router>>FW>>F5 DNS>>F5 LTM>>server

    how to map VIP private IP to Real IP?

    listener IP is a private IP do I need to NAT it in internet firewall to real IP?