VM's loose network connectivity after few minutes

[Sprinterfreak]

Hi.
I'am running proxmox on a rockpi-x wich hosts a few tiny routers and telegraf instances.

After a recent dist-update from basicly 5.4.98-1-pve to 5.4.106-1-pve on the host one openwrt (gluon) based vm shows unstable network connectivity.
The vm has 5 NICs configured of wich two of them net3,net4 are used to pass access to vlans via vlan aware vmbr0+tag to the vm.

Consistently after a couple minutes theese two interfaces stop forwarding packets now.
Theese interfces connect to vlan's wich are used to carry batman-adv encapsulated in vxlan-traffic.
If forward stopps, nothing is logged to syslog, messages etc. neither on the host nor inside vm.
Interface down/up fixes the issue temporarely.

Kernel inside vm is openwrt 4.14.193 custom built wich I don't suspect is the couldprit. Ran fine before host-upgrade.

- NDP yes
- RA yes
- DHCP yes
- even with Firewall off
- same result with virtio-net, e1000, rtl
- same result with i440fx and q35
- same result after re-installing vm
- same result after booting previous pve-kernel via grub - so I suspect the issue in user-space on the host

I'am out of ideas what else to look for...
Does this ring a bell for anyone?

Regards

 

[Sprinterfreak]

This issue still persists.

What I've configured above was
host:
- vmbr0 vlan aware with enp1s0 as slave
vm:
- net3 vmbr0 tag 97
- net4 vmbr0 tag 98
In this case net3 and net4 stop forwarding packets after about a minute.

What I've tried now, wich runs stable
host:
- vmbr0 without vlan aware and enp1s0 as slave
- vmbr97 without vlan aware and enp1s0.97 as slave
- vmbr98 without vlan aware and enp1s0.98 as slave
vm:
- net3 vmbr97
- net4 vmbr98

Now the question: Why does the first not work and the latter does?
I'm not particurlaly happy with the latter approach, because it exposes the hosts ip stack into the dmz network.

 

[Sprinterfreak]

Turns out disabling multicast_snooping on the proxmox host has solved connectivity issues so far.

echo -n 0 > /sys/class/net/*/bridge/multicast_snooping