Passthrough

Sooner or later almost every Proxmox host grows a USB device that needs to talk to one specific guest. A Zigbee or Z-Wave radio for Home Assistant, a TV tuner for a media server, a serial adapter for a UPS, a security dongle for some old piece of software that still checks for one. Getting that device into the right VM or container is usually simple the first time and then mysteriously stops working after the next reboot, because the setup that worked was tied to something that wasn’t actually stable. Here’s how passthrough actually works for both VMs and LXCs, and where the stability problem comes from. ...

Buying the right GPU for your homelab is one decision. Getting Proxmox to actually hand that GPU to a VM or container is a separate one, and it’s where a lot of people get stuck, because Proxmox actually supports two completely different ways to do it, and picking the wrong one for the job means either a fight with IOMMU groups you didn’t need to have, or a container that can’t do what you needed a full GPU for. Here’s what each path actually requires, and how to pick between them. ...