I found it was the installation of ifupdown2 that caused grief. I only installed it since the GUI suggested it is needed to apply networking configurations. After apt remove ifupdown2 and verifying ifenslave is already installed the vlan directives work.
I believe this is what you were...
The 10.10.10.0/24 subnet is used for cluster network traffic between proxmox nodes. It's what I do to isolate it from front end traffic on the 10.0.0.0/16 subnet.
The proxmox gui is front facing so I use https://10.0.1.11:8006 to access the gui.
I have also used additional vlans within...
I should also mention that the below configuration used to work but doesn't anymore. I don't have the faintest clue why either. This morning my cluster nodes weren't seeing each other and the vlan detail above is what fixed it. The only hint I noticed was in the gui the vlan parameters where...
Here's my actual running config with using bonding for 802.3ad , 802.1Q VLAN 5 and Jumbo Frames. I had to apt install ifenslave but that may not be necessary now.
iface lo inet loopback
iface eno1 inet manual
iface enxd03745bf33e4 inet...