Proxmox reload ifupdown2 network config from cli

The correct way to remove nod from proxmox cluster.

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Debian
Description:	Debian GNU/Linux 11 (bullseye)
Release:	11
Codename:	bullseye

Install ifupdown2 package which is a ifupdown re-written in Python.

apt get install ifupdown2

Display utility version.

$ ifreload --version

Inspect configuration for network interfaces.

$ cat /etc/network/interfaces
auto lo
iface lo inet loopback

iface enp2s0 inet manual

auto vmbr0
iface vmbr0 inet static
        bridge-ports enp2s0 
        bridge-stp off
        bridge-fd 0

auto vxlan100
iface vxlan100
  vxlan-id 100

auto vmbr100
iface vmbr100
  bridge-ports vxlan100
  post-up bridge fdb add 00:00:00:00:00:00 dev vxlan100 dst
# Check configuration syntax.
$ sudo ifreload --syntax-check --all

# Check configuration syntax using verbose mode.
$ sudo ifreload --syntax-check --all --verbose

# Check configuration syntax using debug mode.
$ sudo ifreload --syntax-check --all --debug

# Perform a verbose dry run.
$ sudo ifreload --no-act --all --verbose

# Reload network configuration.
$ ifreload --all

Simple, but useful utility.