Fix for community.general.proxmox (now community.proxmox.proxmox) dynamic inventory not setting ansible_host for QEMU VMs with DHCP networking. Without this, you need -e ansible_host=192.168.1.x every time you target the VM.

The Problem

The Proxmox inventory plugin has want_proxmox_nodes_ansible_host for nodes, but nothing equivalent for QEMU guests. For VMs using cloud-init with ip=dhcp, the plugin sets proxmox_ipconfig0 to:

{"ip": "dhcp"}

Not an actual address. The documented compose example from the plugin docs:

compose:
  ansible_host: proxmox_ipconfig0.ip | default(proxmox_net0.ip) | ipaddr('address')

doesn’t help — "dhcp" isn’t an IP, and proxmox_net0 only contains the MAC address and bridge config, not an IP.

The Solution

If the QEMU guest agent is running (agent: 1 in the VM config), the inventory plugin populates proxmox_agent_interfaces with live network data from inside the VM. This includes actual DHCP-assigned addresses.

The tricky part: the agent data uses hyphenated keys (ip-addresses, mac-address) which Jinja2 interprets as subtraction. You can’t use map(attribute='ip-addresses') — it parses as attribute='ip' - addresses. Use .get('ip-addresses', []) instead.

compose:
  ansible_host: >-
    ((proxmox_agent_interfaces | default([])
    | selectattr('name', 'equalto', 'eth0') | list | first | default({}))
    .get('ip-addresses', [])
    | ansible.utils.ipv4 | first | default(''))
    | ansible.utils.ipaddr('address')
    | default(ansible_host | default(inventory_hostname, true), true)

What this does:

  1. Finds the eth0 interface in proxmox_agent_interfaces
  2. Extracts its ip-addresses list (working around the hyphenated key)
  3. Filters to IPv4 only with ansible.utils.ipv4
  4. Strips the CIDR suffix (192.168.1.83/24 → 192.168.1.83)
  5. Falls back to existing ansible_host or inventory_hostname for hosts without agent data

The default(..., true) at the end is important — without the second argument, Jinja2’s default only triggers on undefined variables, not on None or False. The ipaddr filter returns False for invalid input, and want_proxmox_nodes_ansible_host can set ansible_host to None.

Requirements

  • QEMU guest agent installed and running in the VM
  • agent: 1 in the VM config (so Proxmox queries the agent)
  • want_facts: true in the inventory plugin config
  • ansible.utils collection (included with the full ansible package)
  • netaddr Python library (pulled in as a dependency of ansible.utils)

Verification

ansible-inventory -i inventory/pve.proxmox.yaml --list 2>/dev/null \
  | python3 -c "
import json, sys
data = json.load(sys.stdin)
for host, vars in data['_meta']['hostvars'].items():
    print(f\"{host}: {vars.get('ansible_host', 'NOT SET')}\")"

homeassistant: homeassistant
pve: pve
tank: tank
ubuntu-cloud: 192.168.1.83