Bug#931173: Configuring static networking via NoCloud with Network Config Version 2 does not work

[Sven Bartscher <kritzefitz@debian.org>]

Package: cloud-init
Version: 18.3-6
Severity: normal

I was trying to start a machine with a static network setup using
cloud-init. I supplied cloud-init with the following data on a NoCloud
ISO image:

/meta-data:
instance-id: iid-foo-1
local-hostname: foo

/user-data:
#cloud-config
chpasswd: { expire: False }
password: <removed>
ssh_authorized_keys:
  - <removed>
ssh_pwauth: True
timezone: Europe/Berlin
users:
  - default

/network-config:
version: 2
ethernets:
  enp1s0:
    match:
      macaddress: "52:54:00:95:3b:42"
    addresses:
      - 192.168.123.2/255.255.255.0
    gateway4: 192.168.123.1

The specified network-config doesn't seem to have any actual effect on
what actually happens when the system boots. From what I see,
cloud-init generates a configuration file from my specified
configuration in /etc/network/interfaces.d/50-cloud-init.cfg with the
following contents:

# 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}
auto lo
iface lo inet loopback

auto enp1s0
iface enp1s0 inet static
    address 192.168.123.2/24
    gateway 192.168.123.1

but the file apparently has not effect, as
/run/network/interfaces.d/enp1s0 seems to have precedence and
apparently always uses dhcp for the interface.

I also tried to use the set-name option of the Network Configuration
Version 2 format, to change the name of the interface, but apparently
that really confuses ifup, because it still tries to bring up the old
interface name.

-- System Information:
Debian Release: 10.0
  APT prefers testing-debug
  APT policy: (990, 'testing-debug'), (990, 'testing'), (102, 'unstable-debug'), (102, 'unstable'), (101, 'experimental-debug'), (101, 'experimental')
Architecture: amd64 (x86_64)

Kernel: Linux 4.19.0-5-amd64 (SMP w/4 CPU cores)
Locale: LANG=de_DE.utf8, LC_CTYPE=de_DE.utf8 (charmap=UTF-8), LANGUAGE=de_DE.utf8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled

Versions of packages cloud-init depends on:
ii  cloud-guest-utils   0.29-1
ii  fdisk               2.33.1-0.1
ii  gdisk               1.0.3-1.1
ii  ifupdown            0.8.35
ii  locales             2.28-10
ii  lsb-base            10.2019051400
ii  lsb-release         10.2019051400
ii  net-tools           1.60+git20180626.aebd88e-1
ii  procps              2:3.3.15-2
ii  python3             3.7.3-1
pn  python3-configobj   <none>
ii  python3-jinja2      2.10-2
pn  python3-jsonpatch   <none>
ii  python3-jsonschema  2.6.0-4
pn  python3-oauthlib    <none>
ii  python3-requests    2.21.0-1
ii  python3-six         1.12.0-1
ii  python3-yaml        3.13-2
ii  util-linux          2.33.1-0.1

Versions of packages cloud-init recommends:
ii  eatmydata  105-7
ii  sudo       1.8.27-1

Versions of packages cloud-init suggests:
ii  btrfs-progs  4.20.1-2
ii  e2fsprogs    1.44.5-1
ii  xfsprogs     4.20.0-1