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Networking & Storage Sharing

Network model (v0.3.8+)

Microvms use systemd-networkd directly — no cloud-init required.

  • DHCP by default: 20-microvm-dhcp.network matches all ethernet interfaces by Type=ether — no MAC dependency, survives cloning.
  • Static IP: write /etc/microvm-static-net: 
    echo "ADDRESS=10.0.0.5/24 GATEWAY=10.0.0.1 DNS=1.1.1.1" > /etc/microvm-static-net
reboot
  • No cloud-init drive (scsi1) needed.
  • No MAC matching — works with any interface name (eth0, enp0s5, etc.)

Network interfaces

Uses virtio-net-pci-non-transitional with PCIe.

qm set 900 --net0 virtio,bridge=vmbr0              # Single NIC
qm set 900 --net0 virtio,bridge=vmbr0,tag=100       # VLAN

DHCP is configured via cloud-init and systemd-networkd (or dhclient fallback).

Sharing host directories

virtiofs (high performance, needs daemon)

# Host: start sharing before VM boot
pve-microvm-share 900 /path/to/workspace

# Start the VM, then inside guest:
mount -t virtiofs shared /mnt/shared

# Stop sharing:
pve-microvm-share 900 --stop

9p (simpler, no daemon)

# Host: configure before VM boot
pve-microvm-9p 900 /srv/data mytag

# Start VM, then inside guest:
mount -t 9p mytag /mnt/data -o trans=virtio,version=9p2000.L

# Management:
pve-microvm-9p 900 --list
pve-microvm-9p 900 --remove mytag
pve-microvm-9p 900 --clear

Comparison

virtiofs 9p
Daemon virtiofsd required None (QEMU built-in)
Performance Better for large I/O Good for most uses
Setup More complex Simpler
Hot-add No (before boot) No (before boot)

SSH agent forwarding (vsock)

Forward host SSH keys into the guest without exposing them:

# Host:
pve-microvm-ssh-agent 900

# Guest:
export SSH_AUTH_SOCK=/tmp/ssh-agent.sock
socat UNIX-LISTEN:$SSH_AUTH_SOCK,fork VSOCK-CONNECT:2:2222 &
ssh-add -l              # lists host keys
git clone git@github.com:org/repo.git

vsock communication

Each microvm gets a vsock CID (VMID + 1000). Host and guest communicate without networking:

# Host → Guest:
socat - VSOCK-CONNECT:<cid>:<port>

# Guest → Host (CID 2 = host):
socat - VSOCK-CONNECT:2:<port>