Hello everyone,
I have the following scenario:
* 2 host machines (H1 and H2) running VMs. I execute migrations (QEMU)
from one host to the other, and so on. The migrations are done in a
dedicated LAN (eth1 in both hosts) while regular department LAN runs on eth0
* 1 computer (my desktop computer) also connected to this common LAN on
eth0.
The VMs have a Python script sending UDP packets to my desktop computer
(which has the server part of the Python script), every 250 ms, to be
able to mesure downtime and other stuff. Once I run a live migration
from H1 to H2, I would expect the downtime to be in the order of ms, or
maybe a few seconds, but it takes something like 10 to 20 seconds on
average for the packets to resume arriving at my computer. One could
think about the network reconfiguration delay, or other reasons, but
here comes the tricky part:
If I have a ping running on the destination host to the internal IP that
the VM is supposed to have once the migration is done, the UDP packets
resume just a few ms after the migration os done.
Is like: if the VM only has outgoing connections, it takes a lot of time
to resume its operation, but if it has some incoming connection, the
network resumes very quick.
I know it may sound wierd, but maybe there is a clear reason for this
issue. Any ideas?
Thank you!