No network after upgrading to latest kernel (pve 5.4)

[limone]

Hi, when I upgraded to the newest kernel (4.15.18-23-pve) the machine cannot find interface ens3 anymore.
I wanted to upgrade to 6.0, but I guess thats only working when you're on the latest kernel.

If i boot into 4.15.18-15 everything works fine.

auto lo
iface lo inet loopback

allow-hotplug ens3
iface ens3 inet static
        address  123.123.123.123
        netmask  255.255.255.0
        gateway  123.123.123.1

        post-up "ip addr a 111.111.111.111/32 dev ens3"

by the way pve5to6 shows "FAIL: Resolved node IP '123.123.123.123' not configured or active for 'pve'"
but my /etc/hosts is

127.0.0.1       localhost
123.123.123.123  pve.example.org   pve     pvelocalhost

# The following lines are desirable for IPv6 capable hosts
::1     localhost ip6-localhost ip6-loopback
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters

any idea how to debug that? i could'nt find anything suspicious in syslog or dmesg

 

[Stoiko Ivanov]

Hmm - on a hunch - maybe ens13 got renamed with the kernel-upgrade (usually this happens sometimes with BIOS upgrades, but I think I remember a case where a kernel-update changed the predictable network name [0])

boot into the newest kernel and run:

ip link
ip a

that should show you which name all network devices have - if it changed adapt /etc/network/interfaces accordingly

I hope this helps!
[0]https://www.freedesktop.org/wiki/Software/systemd/PredictableNetworkInterfaceNames/

 

[limone]

Thanks, it changed to eth0.
I don't know if there was a bios update, as it's just a kvm which i run proxmox on, maybe the host did the updates.

I saw in dmesg (i think) that eth0 was renamed to ens3, so i thought everything is as it's supposed to be.
ip a didnt show ens3 or eth0, probably because it wasn't configured.

 

[Stoiko Ivanov]

Thanks, it changed to eth0.

That's odd and usually means some manual configuration in a systemd config file (overriding the default from '/lib/systemd/network/99-default.link')

AFAIR the upgrade to PVE6/Debian buster depracates the old network names (eth0,...) - so maybe try to get that fixed

I hope this helps!

 

[limone]

Hmm I didnt change anything, the content is

[Link]
NamePolicy=kernel database onboard slot path
MACAddressPolicy=persistent

I'll just see what happens after upgrading to 6

 

[limone]

Okay the upgrade went fine, but for some reason all my post-up rules don't work anymore, e.g.

auto vmbr0
iface vmbr0 inet static
    address  10.10.10.1
    netmask  255.255.255.0
    bridge-ports none
    bridge-stp off
    bridge-fd 0

    post-up   iptables -t nat -A POSTROUTING -s '10.10.10.0/24' -o eth0 -j MASQUERADE
    post-down iptables -t nat -D POSTROUTING -s '10.10.10.0/24' -o eth0 -j MASQUERADE

any idea why? network interface is still eth0

nevermind another reboot fixed it