On Mon, Nov 29, 2021 at 11:47 PM Nathanaël Blanchet <blanchet@abes.fr> wrote:
Hi all,


I 've finished migration from 4.4.4 to 4.4.9 and I'm facing a strange
issue with routing table on my hosts: all IP addressed interfaces (and
in particular gluster and migration ones that requiere an IP) are not
part of the "254" or "0" usual ip rule.

Only network with default route role will be in the default table (254). This has been the case for quite a while.
What has changed in 4.4.8 is that now NetworkManager is aware of that, before the routes were managed outside of
NM and it might have caused some issues.

for instance:

[root@fuego ~]# nmcli con sh gluster |grep ipv4.route-table
ipv4.route-table:                       202179335

[root@fuego ~]# nmcli con sh migration |grep ipv4.route-table
ipv4.route-table:                       316605387

but ovirtmgmt:

[root@fuego ~]# nmcli con sh ovirtmgmt |grep ipv4.route-table
ipv4.route-table:                       254 (main)

and obviously the main route table is empty:

[root@ ~]# ip ro
default via dev ovirtmgmt proto dhcp metric 425 dev ovirtmgmt proto kernel scope link src
metric 425

Well the main table should contain only the default route gateway.
You can take a look at other routes by:
ip route show table all

None of the concerned hosts can ping each other on such interface, and
live migrations systematically fail.

That might be a different issue related to BZ#2022354. To check if that's really the case
please take a look into oVirt engine and there you should see all affected networks out-of-sync.
On the BZ there are two possible workarounds.

This behaviour is new with 4.4.9 and I don't know if it is a new (and
not achevied) network feature introduced with centos stream to deal
network filtering packets.

A simple workaround would be "nmcli connection mod migration
ipv4.route-table 0 && nmcli con up migration", but I'd like to
understand why such  strange (and unuseful ?) rule table are now
randomly attributed?

I would highly suggest against that because the default route in the default table should be only one, with exception to some backup scenarios.

Nathanaël Blanchet

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Let us know if it's the mentioned bug, if not we can investigate deeper what might be wrong.

Thank you.
Best Regards,


Ales Musil

Software Engineer - RHV Network

Red Hat EMEA

amusil@redhat.com    IM: amusil