Re: autostart fails on host boot. NAT-bridge doesn't come up fast enough
On 8/26/24 12:33 PM, Fred Clift wrote:
I have 18 VMs that are all supposed to attach to a NAT-bridge.
The bridge definition seems to be ok - it used to work when I didn't
have any guests defined. It worked when I had only a couple guests
defined. Now that I have 18 of them, it seems to take more than a
minute for virbr0 to come up, and the guests all fail to autostart
because the bridge doesn't exist yet.
Are your guest interfaces defined with "<interface type='network'> ...
<source network='default'/>"? Or are they defined with
"<interface
type='bridge'> ... <source bridge='virbr0'/>"?
If it's the former, then libvirt *should* make sure that the network is
started by the time any guest needs it (perhaps that changed when we
switched to having a separate daemon for the network driver and the qemu
driver, and we just never noticed it until now?) If this isn't working
properly, we should definitely fix it.
However, if your guest configs are using the latter config, then there
is no official guarantee that the virtual network will be active (and
thus the virbr0 bridge will be available) when the guest starts.
If you can verify which method your guests are using, that could affect
the direction of investigation.
The host system (AlmaLinux 9.4) has dual Xeon(R) CPU E5-2680v4 with
plenty of cores and ram.
Is there some easy way to delay the start of the guests to wait for
virbr0 to be up? Or can I specify a boot order? I assume that
libvirtd autostarts networks before guests but I really have no
idea... Can I specify an autostart dependency?
As a stopgap measure I turned 'autostart' off on these and made a
systemd-run bash script that just starts the network, and then starts
the guests all serially. It has worked 10 or so test boots in a row.
I'd prefer not to have to use an external script if possible.
Fred Clift