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GTM Device groups

Hello,

I have 2 F5 DNS clusters in two datacenters acting as external DNS server. Each cluster should be able to operate fully standalone to server requests for a specific domain. How I see it I should create a device group for both units in DC_US and a another device group for both units in DC_EU. Each device group wil only synchronize configuration data within the local cluster.

Besides this, is there an option to synchronize data between both DNS groups (like GSLB pools per DC) within impacting the 'local'cluster?

Thanks :-)

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USER ACCEPTED ANSWER & F5 ACCEPTED ANSWER

The HA configuration "local" has no relation with GTM Sync Group. You can have an HA configuration,... active/standby, active/active.

GTM is always standalone (and implicitly active). If you have more than one GTM, they will work together. For example, splitting work (like monitor), and sharing data (DNS zone files, WIPs, DNS pools).

When you have LTM and GTM together, LTM will still work independently from the GTM, but you can configure the GTM to take advantage of "local" HA clustering.

The GTM listener is a LTM virtual server for all intents and purposes. If you use the floating IP, only the active unit will respond to queries. If you configure the GTM devices with Listeners using the non-floating self IP, both can process DNS requests. Keep in mind the last scenario means that the DNS clients will have both IPs configured for DNS Servers.

More simply put, the HA "local" clustering, and the GTM Sync group clustering are completely separate.

Based on your overview, I would think you would want two HA clusters with one listener each. And all 4 GTM devices, in a sync group, sharing all DNS information (Bind, WIPs, GTM Pools,,.. and so on.). Also, depending on how you monitor the resources, use prober pools to keep the heavy lifting localized.

Hope it helps!

Good luck!

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Comments on this Answer
Comment made 1 month ago by Kees Smit 4

Excellent, thankyou for this clear explanation. I was able to configure my platform completely and this information helped me understanding the basics and thus configure accordingly. Only thing nagging me was a missing route to my NTP server (via the management interface) which resulted in strange sync behaviour :-)

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USER ACCEPTED ANSWER & F5 ACCEPTED ANSWER

There are many ways to do this - GTM does not often use LTM failover for the listener ( though it can ). Ideally, you want your GTMs to all be in sync so if this were me then i would have 4 GTMs, all in a single sync group.

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Comment made 2 months ago by Kees Smit 4

I'm a bit puzzled here:

Traffic groups are the core component of failover. A traffic group is a collection of related configuration objects, such as a floating self IP address, a floating virtual IP address, and a SNAT translation address, that run on a BIG-IP® device. Together, these objects process a particular type of application traffic on that device.

I want to keep my floating addresses within the DC....

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Comment made 2 months ago by Pete White

OK, so you can also use floating IP addresses and LTM failover if you want to.

Even so, ensure that all 4 devices are in the same GTM sync group.

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Comment made 1 month ago by Kees Smit 4

Thank you for helping out ! Combining your answers helped me a lot !

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