Re: [RFC proxmox{,-backup} 0/2] fix #7198: count veth uplink for PBS running in an LXC

[Jakob Klocker <j.klocker@proxmox.com>]

Sorry for the noise, this was meant for the PBS ML.

On 7/7/26 12:56 PM, Jakob Klocker wrote:
> When PBS runs inside an LXC container, network traffic graphs stay
> empty for interfaces with non-standard names (e.g. wan0, vxb01). The
> reporter [0] observed that renaming to eth0 and restarting made data
> appear.
> 
> The cause is in collect_netdev_stats(): an interface is recorded as
> NetdevType::Physical only if is_physical() returns true. Inside a
> container the uplink is one end of a veth pair (info_kind = "veth"), so
> is_physical() returns false and the code falls back to
> PHYSICAL_NIC_REGEX, which only matches conventional names. A standard
> name like eth0 matches the regex and is counted; a custom name does 
> not, so its stats are silently dropped. In a VM the guest NIC appears
> as a normal hardware NIC without info_kind, which is why the VM case
> works.
> 
> This series adds is_veth() to proxmox-network-api and gates the
> collector on whether PBS runs in a container (checking
> /run/systemd/container). 
> 
> 
> RFC / open questions:
> 
> This patch fixes the reported single-uplink case, but in a container 
> with several veths it counts all of them, including a veth enslaved to 
> a bridge. In testing (see below) a bridge-enslaved veth was still 
> counted. An alternative would be to count root-level interfaces without 
> a master instead of matching veth, which would exclude enslaved 
> interfaces and also generalise beyond veth.
> Also this fix does not work if PBS is run in docker/podman,
> since the interface is not a veth there (it was `tap` in podman).
> LXC is the case that matters for PVE, so not covering podman/docker
> seems acceptable to me.
> 
> 
> Related, not fixed here:
> 
> NETWORK_INTERFACE_CACHE is a OnceLock populated once at proxy startup 
> and never refreshed, so interfaces added or renamed after startup are 
> not picked up until a restart. This matches the reporter's note that a
> restart was required. It's pre-existing and independent of this fix.
> 
> 
> Testing:
> 
> Reproduced in a PVE LXC running PBS with a custom-named veth uplink
> ("test"). Before: the interface produces no graph data. After: it is
> counted. Verified via a temporary debug print in the collector that:
> 
>   * the custom-named veth uplink is counted,
>   * a bridge (info_kind = bridge) is correctly excluded,
>   * with multiple veths present, all veths are counted, including a
>     bridge-enslaved one - the limitation noted above.
> 
> [0] https://bugzilla.proxmox.com/show_bug.cgi?id=7198
> 
> 
> proxmox:
> 
> Jakob Klocker (1):
>   network-api: add is_veth helper to IpLink
> 
>  proxmox-network-api/src/config/helper.rs | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> 
> proxmox-backup:
> 
> Jakob Klocker (1):
>   fix #7198: metric collection: count veth uplink when running in a
>     container
> 
>  src/server/metric_collection/mod.rs | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
> 
> 
> Summary over all repositories:
>   2 files changed, 20 insertions(+), 1 deletions(-)
>