ProxmoxVE: nameservers not configured if multiple nameservers are provided in network-data

[mx-shift]

Bug

Configuring a Proxmox VM with the following network-config causes the IP and gateway to be set during early boot but no nameservers are configured:

version: 1
config:
    - type: physical
      name: eth0
      mac_address: 'bc:24:11:e5:98:ff'
      subnets:
      - type: static
        address: '192.168.88.43'
        netmask: '255.255.255.0'
        gateway: '192.168.88.1'
    - type: nameserver
      address:
      - '192.168.88.30'
      - '192.168.88.31'

using a single nameserver works correctly.

Operating System Version

Fedora CoreOS 42.20250705.1.0

Afterburn Version

Afterburn-multi 5.8.2

Environment

What hardware/cloud provider/hypervisor is being used to run Afterburn?

Proxmox VE 8.4.1

Expected Behavior

[root@test ~]# resolvectl
Global
Protocols: LLMNR=resolve -mDNS -DNSOverTLS DNSSEC=no/unsupported
resolv.conf mode: stub

Link 2 (ens18)
Current Scopes: DNS LLMNR/IPv4 LLMNR/IPv6
Protocols: +DefaultRoute LLMNR=resolve -mDNS -DNSOverTLS DNSSEC=no/unsupported
Current DNS Server: 192.168.88.30
DNS Servers: 192.168.88.30
Default Route: yes

## Actual Behavior ##

[root@test ~]# resolvectl
Global
Protocols: LLMNR=resolve -mDNS -DNSOverTLS DNSSEC=no/unsupported
resolv.conf mode: stub

Link 2 (ens18)
Current Scopes: LLMNR/IPv4 LLMNR/IPv6
Protocols: -DefaultRoute LLMNR=resolve -mDNS -DNSOverTLS DNSSEC=no/unsupported
Default Route: no

## Reproduction Steps ##

  1. Create a new Proxmox VM
  2. Import https://builds.coreos.fedoraproject.org/prod/streams/next/builds/42.20250705.1.0/x86_64/fedora-coreos-42.20250705.1.0-proxmoxve.x86_64.qcow2.xz as the root disk 
  3. Add a cloud-init drive
  4. Configure IP, gateway, and two nameservers in Proxmox's cloud-init UI
  5. Boot the OS
  6. Run `resolvectl` and see no nameservers are configured
  7. Check /etc/NetworkManager/system-connections/default_connection.nmconnection and see no nameservers are configured
 
 ## Other Information ##

https://github.com/coreos/afterburn/blob/main/src/providers/proxmoxve/cloudconfig.rs#L246 seems to be wrong.  According to https://www.man7.org/linux/man-pages/man7/dracut.cmdline.7.html, each nameserver needs a separate nameserver= argument, not commas.