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Herman2024's avatar
Herman2024
Icon for Nimbostratus rankNimbostratus
Sep 17, 2024

dns config is not sync to standby f5 for HA cluster

Hi , I have setup a HA cluster big-ip, the virtual server will be automatically created on standby unit, but any config under DNS is not sync to standby unit. Is it normal ? I am new to f5, anyone please help advise, thanks in advance!

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  • mkyrc's avatar
    mkyrc
    Icon for Cirrus rankCirrus
    Sep 17, 2024

    Hello,
    sync between "DNS/GTM" is based on different way as "LTM". HA between DNS devices is required only if you need configure cluster of DNS devices (for DNS listener - it is virtual server in background). When you have independent DNS/GTM devices (in different geo locations) HA is not required.

    For sync configuration data between DNS devices (data centers, servers, prober pools, wide IPs, pools, etc) you need configure several parts. In short:

    1. install the same version of big3d on all devices (`big3d_install <peer-device>` is you friend)
    2. exchange device certs (`big_add <peer>`)
    3. configure sync group (DNS -> Settings -> GSLB -> General) and there check "synchronize" and (recommended) set "group name"
    4. add another gtm to "sync group" (`gtm_add`). Be carefully, LOCAL config will be replaced by remote config.
    5. ^^ sync group is created.

    Good to know:

    • DNS devices are synced over "data" interface (not "mgmt" or "HA"), because they can sit on different data centers around the world
    • You need to add all DNS members (in sync group) in server list (not only "LTM" or "generic" hosts where virtual servers are running). This is very common mistake when DNS sync is not working.

    You can find more details about DNS sync here: https://my.f5.com/manage/s/article/K45907236

    Martin