GTM Design | LTM+ ASM+GTM on same VM
Dears,
I am planning to publish the same service through two sites by LTM and ASM. Each site has two F5 VMs (LTM and ASM).
The customer is required to make the two sites active-active, we recommend using GTM.
My questions:
1- Do we need GTM at each site or we can use one GTM and one of the two sites? and what is the best practice?
2- Are we can add LTM+ASM+GTM at the same VM or do we need to separate GTM?
3- How can I publish GTM? I need the full design.
4- If I need to publish GTM through two ISPs, Is i need two public IPs or one IP enough?
Hi,
My answers based on a few similar projects:
1- You can have one GTM, but it won't provide true NS redundancy. Best practice I've seen is to have at least two NS geographically separated, each NS pointing to a GTM cluster (2VMs per site to provide in-site F5 redundancy). Other advanced architecture have more NS but same number of F5s by adding secondary ISP link to the mentioned GTMs
2- In theory you can have the three modules in the same VM (I recommend 16GB of RAM) but in practice it's better to have GTM in a separated VM and separated subnet.
3- There's two parts: where to position GTM? and how to handle DNS requests? For the first I usually prefer to have DNS as close as possible to the WAN edge router. For the second, you usually delegate a subdomain, or if managing all your domain by GTM you can point the entire domain to your GTM listeners
4- Two IPs, one for each ISP