CentOS - Oct 2019 - Odd issue with 7.7.1908 updated with qemu-kvm-ev

So, I have a client that has an internal use application that needs an 
ancient version of libc5.? That's not a typo; libc5.? Before the server 
that ran it died about a year and a half ago (said server was an AMD 
K6-2/450 with a 6GB Western Digital Caviar drive that had been spinning 
nearly continuously for almost 20 years!) it was running on Red Hat 
Linux 5.2.? The last version of CentOS that shipped with a libc5 was 
2.1.? So I set them up a KVM guest running CentOS 2.1, mainly because 
Red Hat 5.2 wouldn't recognize the network at all, using the e1000 
network driver, and it ran well.

Now, yes, there are no updates, but no it doesn't matter; it's an 
internal use application that has a very small footprint and very low risk.

After the update on the host to 7.7.1908, the network stopped running.? 
The host also has a CentOS 7 guest that is still working properly.? If I 
change the 2.1 system to not automatically load the e1000 driver and 
console in and 'modprobe e1000' manually, it starts working again, for a
while.

Any ideas as to where to start looking?? qemu-kvm-ev itself, or 
libvirt?? I'm planning to start out with rollbacks to the previous 
versions of each to try to find where the issue starts.

Hi,
> So, I have a client that has an internal use application that needs an
> ancient version of libc5.? That's not a typo; libc5.? Before the server
> that ran it died about a year and a half ago (said server was an AMD
> K6-2/450 with a 6GB Western Digital Caviar drive that had been spinning
> nearly continuously for almost 20 years!) it was running on Red Hat
> Linux 5.2.? The last version of CentOS that shipped with a libc5 was
> 2.1.? So I set them up a KVM guest running CentOS 2.1, mainly because
> Red Hat 5.2 wouldn't recognize the network at all, using the e1000
> network driver, and it ran well.
>
> Now, yes, there are no updates, but no it doesn't matter; it's an
> internal use application that has a very small footprint and very low
> risk.
>
> After the update on the host to 7.7.1908, the network stopped running.?
> The host also has a CentOS 7 guest that is still working properly.? If I
> change the 2.1 system to not automatically load the e1000 driver and
> console in and 'modprobe e1000' manually, it starts working again,
for a
> while.
Just as a workaround, did you try to use another network card than the e1000?

Simon

On 10/15/19 10:28 AM, Simon Matter via CentOS wrote:
> Hi,
>> ... After the update on the host to 7.7.1908, the network stopped 
>> running. The host also has a CentOS 7 guest that is still working 
>> properly.? If I change the 2.1 system to not automatically load the 
>> e1000 driver and console in and 'modprobe e1000' manually, it
starts
>> working again, for a while. 
> Just as a workaround, did you try to use another network card than the 
> e1000?
Yes, I did; the only other option was for the 8139 NIC, which in CentOS 
2.1 is the '8139too' driver. And it worked; until I rebooted the guest 
and the driver was loaded automatically.? If either driver is loaded 
manually, after the 'ifup eth0' has already been executed, it works, at 
least for a few hours.? There are no virtio drivers that I could find 
for C2.1 (not surprising).

I did forget to mention that this is bridged networking, and is working 
great for the C7 guest that is on the same C7 host.? Even when the C2.1 
guest's connectivity goes down, the bridge shows as up and not blocking.