topic Re: ION HA with dedicated controller port in Prisma SD-WAN Discussions

ION HA with dedicated controller port

Markus_B — Thu, 22 Jun 2023 14:10:57 GMT

Hi everyone,

we recently re-IP'd a set of two ION3000s in an HA group and saw that site losing connectivity at every single step. That got me thinking - these IONs have two controller ports, one of which is completely unused. Can we configure that empty controller port on both IONs to be in some none-routable /30 subnet and connect the IONs directly to each other? We're doing essentially that on all our panOS firewalls already and it works great.

Re: ION HA with dedicated controller port

kn — Fri, 23 Jun 2023 04:12:39 GMT

Hi @Markus_B

In-person, I don't think connecting the ION controller2 interfaces back to back is a smart idea. When the active ION is powered off, the backup ION cannot become operational since its HA-control port (controller2) is likewise shut down.
You may run a fast test on this behavior to confirm the above assertion.

-kn

Re: ION HA with dedicated controller port

Markus_B — Fri, 23 Jun 2023 12:53:12 GMT

Thanks for your reply, @kn

unfortunately, I don't have any lab units to test this with. I also haven't been able to find any technical details on how HA is designed, so I can only speculate. However, let me think your comment a bit further.

You're essentially saying, that an ION in an operational HA-group and passive state will refuse to ever become active, if the port configured for HA-sync is physically down. That would mean, that if I have the controller ports on a physically separate management network and the corresponding switch fails (or the cable gets damaged or unplugged), I lose HA completely. I would personally consider that questionable system design and be worried about deploying these IONs until an Engineer with Palo/Cloudgenix has a very good explanation on why that is. However I assume, that you're guessing as much as I am?

Thanks

Re: ION HA with dedicated controller port

kn — Fri, 23 Jun 2023 13:11:23 GMT

Hi @Markus_B

The possibility you explained with the switch will not face the issue because the drive with an HA-active state will continue its functioning. All my inputs are from experience. and HA logic is similar to VRRP here with Prisma-SDWAN.