HALB Crashing With Kernel Panic

[ChrisS58]

Hello,
We've been using Parallels (version 16) for many years and it has been fairly trouble-free. However, we've recently been experiencing an issue with one of our HALB appliances... it will be running fine and then all of a sudden crash with a kernel panic, which ends-up temporarily disconnecting all of our users who are connected to applications. The system fails over to the secondary HALB and everything continues fine, once everyone re-launches their session.

Here is what I've tried so far:
1) Reboot HALB appliance --> Works for about a day and then crashes again with no warning
2) Delete and reinstall the HALB appliance via the OVA --> Same as above, works for about a day and then crashes

The HALB's are running in our VMWare ESXi environment on two separate hosts. Here is an example of the kernel panic/crash on the console:


I see some references to a knowledge base article regarding HALB Kernel Panic's, however, it appears that the article is no-longer available:
https://kb.parallels.com/128472
I see that newer versions of the HALB can be downloaded, but am not sure if they are compatible with our existing deployment (Version 16).
Has anyone run into this before? Any idea what might be causing the crash and how it can be resolved?
Regards,
Chris

 

[ChrisS58]

Just a further update... it seems that this issue is now affecting both of our HALB appliances. They seem to run for about a day and then will randomly crash with a kernel panic. There's lots of memory free and disk space, CPU utilization is low. At a bit of a loss of what could be happening here, although, after some digging it looks like it could be some sort of bug with the kernel / IP Tables module? Hopefully there's some sort of quick fix or work-around? It's just bizarre as these have been running for 7-8 years completely trouble free until a week ago.
Any ideas??

 

[TylerD9]

Hey Chris,

I think your best course of action would be to upgrade to a modern build. The old appliances may be using packages that are really out of date, and potentially vulnerable. Are these exposed to the public internet? If so, someone could be trying to exploit them causing the kernel panics.

Kernel 3.2.68-1 was released in 2012 and may also not properly support modern hardware.

 

[ChrisS58]

Thanks - No, these aren't public-facing and are behind a hardware firewall on a private network. I did some further testing and have confirmed that the problem lies with the IP Tables kernel module. When this is disabled, the appliance functions properly with no crashing.

-Chris