Hi Ryan, [Journal Output] Attached.
[Reproducer] uvt-kvm create xenial-test release=xenial arch=amd64 virsh edit xenial-test # change network interface pci slot: s/0x03/0x10/ virsh destroy xenial-test virsh start xenial-test uvt-kvm ssh xenial-test dmesg|grep rename [ 2.790623] virtio_net virtio3 ens16: renamed from eth0 [ 6.048520] virtio_net virtio3 ens3: renamed from ens16 [Analysis] I've been working on this a lot, and I think I have the cause of the difference. In udev-events.c, udev_execute_rules will _forcibly_ rename a device with via a netlink message if there is a matching rule that sets a name. Under Xenial, there *is* a matching rule, in 70-persistent-net.rules, so this forces a rename. This rename will occur even if the device already has a name, and therefore even if the rules file isn't in the initramfs. Under Bionic, this rules file doesn't exist, there is a .link file instead. Unfortunately, a name in a .link file will only take effect if the device hasn't been renamed - because of the renaming in initrd, this means that a link file that is not present in the initrd will never be able to cause a rename. [Solutions] There are a couple of ways we could fix this that come to mind: - make netplan generate a file in /run/udev/rules.d for each device - make systemd rename devices from a link file even if they've been renamed My preference is the first, but I'm open to anything we can get upstream. Thanks again. Regards, Daniel ** Attachment added: "journalctl -b output on Xenial VM with multiple renames" https://bugs.launchpad.net/netplan/+bug/1770082/+attachment/5139894/+files/journalctl-b.txt -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to systemd in Ubuntu. https://bugs.launchpad.net/bugs/1770082 Title: systemd-networkd not renaming devices on boot Status in netplan: Incomplete Status in systemd package in Ubuntu: New Bug description: === systemd issue === Renaming devices doesn't seem to work. If I disable all other network configuration and create /etc/systemd/network/10-network.link with: [Match] MACAddress=52:54:00:c1:c9:bb [Link] Name=myiface3 I expect this to cause the device with that MAC address to be renamed to myiface3. However, when I reboot, I instead see: $ ip l 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN mode DEFAULT group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN mode DEFAULT group default qlen 1000 link/ether 52:54:00:c1:c9:bb brd ff:ff:ff:ff:ff:ff The device is not renamed. This link file is pretty much identical to Example 2 in https://www.freedesktop.org/software/systemd/man/systemd.link.html. The renaming does work if I boot with net.ifnames=0, and oddly, it also works if I unbind the device and rebind it as netplan apply does. No setting of NamePolicy seems to help. === Original Bug == 'set-name:' doesn't change the name of a network interface on boot, it only works when you do netplan apply. Say I take this 50-cloud-init.yaml file: # This file is generated from information provided by # the datasource. Changes to it will not persist across an instance. # To disable cloud-init's network configuration capabilities, write a file # /etc/cloud/cloud.cfg.d/99-disable-network-config.cfg with the following: # network: {config: disabled} network: version: 2 ethernets: ens3: dhcp4: true match: macaddress: 52:54:00:de:bd:f6 set-name: ens3 Say I change set-name to 'myiface3' and reboot. I expect that the device will be called myiface3 and brought up fine with dhcp. However, instead I see: $ ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 2: ens3: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000 link/ether 52:54:00:de:bd:f6 brd ff:ff:ff:ff:ff:ff The name has not been changed, and the device has not been brought up. If I run netplan apply however, I see the following: 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000 link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00 inet 127.0.0.1/8 scope host lo valid_lft forever preferred_lft forever inet6 ::1/128 scope host valid_lft forever preferred_lft forever 3: myiface3: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000 link/ether 52:54:00:de:bd:f6 brd ff:ff:ff:ff:ff:ff inet 192.168.122.151/24 brd 192.168.122.255 scope global dynamic myiface3 valid_lft 3575sec preferred_lft 3575sec inet6 fe80::5054:ff:fede:bdf6/64 scope link valid_lft forever preferred_lft forever So names are successfully changed with netplan apply. This seems to be some udev-related timing or priority issue that I'm still trying to hunt down. This breaks some forms of migration in certain cloud environments. 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