OCI VM: initramfs IP=dhcp causes DHCP lease to be persisted as static config

[CMGS]

Problem

OCI VMs on DHCP networks (e.g., dhcp-noipam with no CNI IPAM) get their DHCP lease persisted as a static systemd-networkd config file on first boot. This creates a behavioral inconsistency between source VMs and cloned VMs:

• Source VM (cold boot): initramfs IP=dhcp → configure_networking runs DHCP in initramfs → writes /run/net-eth0.conf → systemd-network-generator converts it to /etc/systemd/network/10-<mac>.network with static Address=/Gateway=/DNS= → subsequent reboots use static IP
• Clone VM (snapshot restore): skips initramfs entirely → post-clone hint writes DHCP=ipv4 config → reboots use DHCP

Same network, same image, different behavior after reboot.

Root Cause

/etc/initramfs-tools/initramfs.conf has IP=dhcp (set in the OCI image Dockerfile). This is intended for kernel ip= parameter bootstrapping, but when no ip= is present, configure_networking falls back to DHCP. The systemd-network-generator service then reads /run/net-*.conf and generates a 10- priority static .network file that overrides the image's 20-wired.network (DHCP=yes).

Observed Behavior

# Source VM (first boot, dhcp-noipam network)
$ cat /etc/systemd/network/10-8639ccd45f70.network
[Match]
MACAddress=86:39:cc:d4:5f:70
[Network]
Address=10.99.0.180/24      # static!
Gateway=10.99.0.1
DNS=10.99.0.1 8.8.8.8

# Clone of same VM (after post-clone hint)
$ cat /etc/systemd/network/10-327dc895e9ae.network
[Match]
MACAddress=32:7d:c8:95:e9:ae
[Network]
DHCP=ipv4                   # dynamic!

Proposed Fix

Remove IP=dhcp from /etc/initramfs-tools/initramfs.conf in the OCI image Dockerfile. The kernel ip= parameter (when present) still triggers configure_networking regardless of the IP= setting — static network configuration for bridge+host-local CNI is unaffected. DHCP networks should be handled entirely by systemd-networkd via the existing 20-wired.network (DHCP=yes).

This ensures both source VMs and cloned VMs have consistent DHCP behavior on DHCP networks.

[CMGS]

Fixed in feature/firecracker branch:

1. IP=off in initramfs.conf — prevents initramfs from running DHCP during boot
2. configure_networking only called when kernel ip= parameter is present — eliminates ~180s hang on --nics 0 VMs
3. All 5 Ubuntu Dockerfiles (22.04, 24.04, 24.04-chrome, 24.04-xface, 24.04-picoclaw) updated

Static IP workflow unchanged: CNI assigns IP → kernel ip= → initramfs writes static networkd config.

DHCP workflow fixed: CNI does bridge+veth+TAP wiring only → no ip= → initramfs skips networking → cocoon-network writes DHCP=ipv4 config → systemd-networkd handles DHCP directly with external DHCP server.

Verified in E2E tests: 0NIC boots in <15s, DHCP VMs get lease from dnsmasq, source/clone behavior consistent.