Network interface name mismatch when using vmbuilder

Question

I created a VM using vmbuilder and it failed to bring up the network interface. I was able to log into the VM using Virtual Machine Manager and saw that the interface in /etc/network/interfaces was eth0, but in networkctl was ens3 (a Predictable Network Interface Name). I looked at /var/log/syslog and found

Oct 17 19:26:43 servername kernel: [ 1.314794] virtio_net virtio0 ens3: renamed from eth0
Oct 17 19:26:43 servername ifup[394]: Cannot find device "eth0"
Oct 17 19:26:43 servername ifup[394]: Failed to bring up eth0.
Oct 17 19:26:43 servername systemd[1]: networking.service: Main process exited, code=exited, status=1/FAILURE
Oct 17 19:26:43 servername systemd[1]: Failed to start Raise network interfaces.
Oct 17 19:26:43 servername systemd[1]: networking.service: Unit entered failed state.
Oct 17 19:26:43 servername systemd[1]: networking.service: Failed with result 'exit-code'.

among the other log entries.

The following are empty or don't exist:

• GRUB_CMDLINE_LINUX="" in /etc/default/grub (and GRUB_CMDLINE_LINUX_DEFAULT="quiet splash")
• /etc/udev/rules.d/70-persistent-net.rules
• /lib/udev/rules.d/75-persistent-net-generator.rules

Here are the interfaces:

$ ls -l /sys/class/net
total 0
lrwxrwxrwx 1 root root 0 Oct 17 20:36 ens3 -> ../../devices/pci0000:00/0000:00:03.0/virtio0/net/ens3
lrwxrwxrwx 1 root root 0 Oct 17 20:36 lo -> ../../devices/virtual/net/lo

Here is the vmbuilder command line I used:

sudo vmbuilder kvm ubuntu --suite xenial --templates /homes/administrator/vmfiles \
    --hostname servername --dest ./servername --rootsize 200000 --mem 16384 \
    --ip 1.1.1.1 --dns 1.1.1.1 --gw 1.1.1.1 --bridge br0 \
    --network=bridge:br0 --timezone=America/Chicago --libvirt qemu:///system \
    --user USER --name USER --pass PASSWORD \
    --ssh-user-key /homes/USER/.ssh/authorized_keys \
    --addpkg linux-image-generic --addpkg openssh-server \
    --addpkg unattended-upgrades --addpkg python-apt --copy vmfiles/copyspecs

As a test, I changed /etc/network/interfaces to refer to ens3 and I was able to bring up the interface.

I'm fine with using Predictable Names, but how do I solve this mismatch?

Answer 1

In searching through the log that vmbuilder created in /tmp, I found that it created /etc/network/interfaces using a template from /etc/vmbuilder/ubuntu/interfaces.tmpl which blindly uses eth0 (or dhcp if that was selected instead of an IP).

This appears to be a bug.