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Wangzixuan_3147's avatar
Wangzixuan_3147
Icon for Nimbostratus rankNimbostratus
Aug 09, 2018

How to change the LC type on GTM from energic-host to bigip

Hello everyone, our customer's topology environment as shown. I found that the GTM did not add the LC as a bigip type server, but instead added it as generic-host, so you can't use the auto discovery feature. Therefore, every time a new application is released, after creating a new VS on the LC, it needs to be re-added on the GTM. This is more troublesome. I don’t know why the engineer was designed like this. What are the benefits of this design? No firewall or address translation in GTM and LC。 And there is no LINK found on GTM? Is there a link on the LC, is the LINK on the GTM optional?

 

Now customers think about changing to bigip server, using auto discovery function, will direct modification affect the virtual server on the previous GTM?

 

application delivery
BIG-IP
BIG-IP DNS

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  • Dan_Pacheco's avatar
    Dan_Pacheco
    Icon for Cirrus rankCirrus
    Aug 09, 2018

    If your LC devices are F5 LTMs you can add them to your GTMs and enable VS discovery.

     

    1. on LTMs ensure client side self IPs allow ports 22 and 4353
    2. In the GTM
    3. Create data centers
    4. Create “Links” for each data center using the IP of the LTM's default gateway.
    5. Create Servers for LTMs select type BIG-IP Redundant
    6. Login with root. From each GTM enter into bash and run bigip_add x.x.x.x (IP= Client side self IP) for both IPs of the LTM redundant pair. After doing this the servers should change from blue to green. Note: Use command iqdump x.x.x.x (IP of target system )to analyze iquery traffic
  • Wangzixuan_3147's avatar
    Wangzixuan_3147
    Icon for Nimbostratus rankNimbostratus
    Aug 10, 2018

    The LC device is F5 LTM. The Data center has been created on the GTM, and the generic-host LC server has been created. Many virtual servers have been created under the server. Now if you change the LC server type from generic-host to bigip type, it will affect the virtual server already built, because the automatically discovered virtual server will conflict with the previous manual. If I want to change the server type, do I have to delete both the previous server and the virtual server.

     

  • Dan_Pacheco's avatar
    Dan_Pacheco
    Icon for Cirrus rankCirrus
    Aug 10, 2018

    You can create new servers in the same datacenter. However, you will have to manually replace the old manually creatwd virtuals with the new ones in each gtm pool. After that you can delete the old generic hosts.

     

  • Wangzixuan_3147's avatar
    Wangzixuan_3147
    Icon for Nimbostratus rankNimbostratus
    Aug 13, 2018

    Okay thank you. Ask another question, the customer only has only one data center physically, and three Datacenters are logically established according to the three ISPs, and Link is not configured. Is there any advantage to configuring the LC as a generic-host server? In fact, I want to know why engineers originally designed this way.

     

  • Dan_Pacheco's avatar
    Dan_Pacheco
    Icon for Cirrus rankCirrus
    Aug 30, 2018

    No, there is no advantage that I can think of to configure an F5 LTM as a generic host. It just gives you less visibility and poorer healthchecks. It is fine/necessary for non-F5 devices.