LeaseWeb DL120 G7 NixOS systemd network interface naming

18.03.txt

# udevadm info /sys/class/net/eno1
P: /devices/pci0000:00/0000:00:1c.5/0000:03:00.0/net/eno1
E: DEVPATH=/devices/pci0000:00/0000:00:1c.5/0000:03:00.0/net/eno1
E: ID_BUS=pci
E: ID_MODEL_FROM_DATABASE=82574L Gigabit Network Connection (NC112i 1-port Ethernet Server Adapter)
E: ID_MODEL_ID=0x10d3
E: ID_NET_LABEL_ONBOARD=enNIC Port 2
E: ID_NET_NAME_MAC=enxe83935edad4b
E: ID_NET_NAME_ONBOARD=eno1
E: ID_NET_NAME_PATH=enp3s0
E: ID_OUI_FROM_DATABASE=Hewlett Packard
E: ID_PCI_CLASS_FROM_DATABASE=Network controller
E: ID_PCI_SUBCLASS_FROM_DATABASE=Ethernet controller
E: ID_VENDOR_FROM_DATABASE=Intel Corporation
E: ID_VENDOR_ID=0x8086
E: IFINDEX=3
E: INTERFACE=eno1
E: PATH=/nix/store/n67bza7f1j6q43w01lsl1kmxppqyb641-udev-path/bin:/nix/store/n67bza7f1j6q43w01lsl1kmxppqyb641-udev-path/sbin
E: SUBSYSTEM=net
E: SYSTEMD_ALIAS=/sys/subsystem/net/devices/eno1 /sys/subsystem/net/devices/eno1
E: TAGS=:systemd:
E: USEC_INITIALIZED=13828199

# udevadm info /sys/class/net/enp2s0
P: /devices/pci0000:00/0000:00:1c.4/0000:02:00.0/net/enp2s0
E: DEVPATH=/devices/pci0000:00/0000:00:1c.4/0000:02:00.0/net/enp2s0
E: ID_BUS=pci
E: ID_MODEL_FROM_DATABASE=82574L Gigabit Network Connection (NC112i 1-port Ethernet Server Adapter)
E: ID_MODEL_ID=0x10d3
E: ID_NET_NAME_MAC=enxe83935edad4a
E: ID_NET_NAME_PATH=enp2s0
E: ID_OUI_FROM_DATABASE=Hewlett Packard
E: ID_PCI_CLASS_FROM_DATABASE=Network controller
E: ID_PCI_SUBCLASS_FROM_DATABASE=Ethernet controller
E: ID_VENDOR_FROM_DATABASE=Intel Corporation
E: ID_VENDOR_ID=0x8086
E: IFINDEX=2
E: INTERFACE=enp2s0
E: PATH=/nix/store/n67bza7f1j6q43w01lsl1kmxppqyb641-udev-path/bin:/nix/store/n67bza7f1j6q43w01lsl1kmxppqyb641-udev-path/sbin
E: SUBSYSTEM=net
E: SYSTEMD_ALIAS=/sys/subsystem/net/devices/enp2s0 /sys/subsystem/net/devices/enp2s0
E: TAGS=:systemd:
E: USEC_INITIALIZED=13820267


# Perhaps relevant, linked by @flokli:
# https://github.com/flokli/systemd/commit/04b67d49254d956d31bcfe80340fb9df7ed332d3
# It reads `name_assign_type`:

# cat /sys/class/net/eno1/name_assign_type 
4

# cat /sys/class/net/enp2s0/name_assign_type 
4

20.03.txt

# udevadm info /sys/class/net/eno0
P: /devices/pci0000:00/0000:00:1c.4/0000:02:00.0/net/eno0
L: 0
E: DEVPATH=/devices/pci0000:00/0000:00:1c.4/0000:02:00.0/net/eno0
E: INTERFACE=eno0
E: IFINDEX=2
E: SUBSYSTEM=net
E: USEC_INITIALIZED=16012713
E: PATH=/nix/store/cc7x9b7ih0m6z0ypa1qc9gwlh9pl1c1y-udev-path/bin:/nix/store/cc7x9b7ih0m6z0ypa1qc9gwlh9pl1c1y-udev-path/sbin
E: ID_NET_NAMING_SCHEME=v243
E: ID_NET_NAME_MAC=enxe83935edad4a
E: ID_OUI_FROM_DATABASE=Hewlett Packard
E: ID_NET_NAME_ONBOARD=eno0
E: ID_NET_LABEL_ONBOARD=NIC Port 1
E: ID_NET_NAME_PATH=enp2s0
E: ID_BUS=pci
E: ID_VENDOR_ID=0x8086
E: ID_MODEL_ID=0x10d3
E: ID_PCI_CLASS_FROM_DATABASE=Network controller
E: ID_PCI_SUBCLASS_FROM_DATABASE=Ethernet controller
E: ID_VENDOR_FROM_DATABASE=Intel Corporation
E: ID_MODEL_FROM_DATABASE=82574L Gigabit Network Connection (NC112i 1-port Ethernet Server Adapter)
E: ID_PATH=pci-0000:02:00.0
E: ID_PATH_TAG=pci-0000_02_00_0
E: ID_NET_DRIVER=e1000e
E: ID_NET_LINK_FILE=/nix/store/xw26cpshps6lapgfpnyn2qfzrrlp4mby-systemd-243.7/lib/systemd/network/99-default.link
E: ID_NET_NAME=eno0
E: SYSTEMD_ALIAS=/sys/subsystem/net/devices/eno0 /sys/subsystem/net/devices/eno0
E: TAGS=:systemd:

# udevadm info /sys/class/net/eno1
P: /devices/pci0000:00/0000:00:1c.5/0000:03:00.0/net/eno1
L: 0
E: DEVPATH=/devices/pci0000:00/0000:00:1c.5/0000:03:00.0/net/eno1
E: INTERFACE=eno1
E: IFINDEX=3
E: SUBSYSTEM=net
E: USEC_INITIALIZED=16024671
E: PATH=/nix/store/cc7x9b7ih0m6z0ypa1qc9gwlh9pl1c1y-udev-path/bin:/nix/store/cc7x9b7ih0m6z0ypa1qc9gwlh9pl1c1y-udev-path/sbin
E: ID_NET_NAMING_SCHEME=v243
E: ID_NET_NAME_MAC=enxe83935edad4b
E: ID_OUI_FROM_DATABASE=Hewlett Packard
E: ID_NET_NAME_ONBOARD=eno1
E: ID_NET_LABEL_ONBOARD=NIC Port 2
E: ID_NET_NAME_PATH=enp3s0
E: ID_BUS=pci
E: ID_VENDOR_ID=0x8086
E: ID_MODEL_ID=0x10d3
E: ID_PCI_CLASS_FROM_DATABASE=Network controller
E: ID_PCI_SUBCLASS_FROM_DATABASE=Ethernet controller
E: ID_VENDOR_FROM_DATABASE=Intel Corporation
E: ID_MODEL_FROM_DATABASE=82574L Gigabit Network Connection (NC112i 1-port Ethernet Server Adapter)
E: ID_PATH=pci-0000:03:00.0
E: ID_PATH_TAG=pci-0000_03_00_0
E: ID_NET_DRIVER=e1000e
E: ID_NET_LINK_FILE=/nix/store/xw26cpshps6lapgfpnyn2qfzrrlp4mby-systemd-243.7/lib/systemd/network/99-default.link
E: ID_NET_NAME=eno1
E: SYSTEMD_ALIAS=/sys/subsystem/net/devices/eno1 /sys/subsystem/net/devices/eno1
E: TAGS=:systemd:


# cat /sys/class/net/eno0/name_assign_type 
4

# cat /sys/class/net/eno1/name_assign_type 
4

Analysis.md

Analysis

On 18.03 the dmesg says:

enp2s0: renamed from eth0
eno1: renamed from eth1

On 20.03 the dmesg says:

eno0: renamed from eth0
eno1: renamed from eth1

Conclusion

With the 20.03 kernel, suddenly both interfaces are marked onboard (ID_NET_LABEL_ONBOARD), when before only one was.

That is why the interface name changed from enp2s0 to eno0.