Virtualization Cheat Sheet

Overview #

OpenBSD’s native hypervisor stack includes:

• vmm(4) : Kernel hypervisor.
• vmd(8) : Virtual machine daemon.
• vmctl(8) : Command-line control utility.

For detailed guidance, see the Handbook’s Virtualization chapter .

Directory Layout #

This example uses /var/vmm/ for VM assets; choose a private location with sufficient space. Create its images and iso subdirectories with root ownership before use.

Disk and Image Creation #

Before starting guests, enable and start vmd with rcctl. Verify downloaded installation media using the release SHA256.sig and matching signify key as described in Installing OpenBSD .

Single OpenBSD VM (Interactive Install) #

doas vmctl create -s 10G /var/vmm/images/obsd.img
doas vmctl start -c -m 1G -r /var/vmm/iso/install79.iso -d /var/vmm/images/obsd.img obsd

• -c: Connect to console.
• -m: Memory (1G = 1024M).
• -r: ISO for installation.
• -d: Disk image.
• Last argument: VM name.

After installation, reboot without ISO:

doas vmctl stop -w obsd
doas vmctl start -c -m 1G -d /var/vmm/images/obsd.img obsd

Networking Options #

vmctl start -n name attaches to an existing named switch. It does not interpret local or tap0 as special network modes. The -L option creates local networking; Internet access still requires host forwarding and PF policy.

Example: Two VMs on Private NAT Network #

Use the complete Virtualization procedure to configure local networking, forwarding, and NAT before starting guests with -L. Creating a disk does not install an operating system in it.

Example: Bridge VMs to Physical LAN #

Create /etc/hostname.bridge0, replacing em1 with the intended LAN interface:

add em1
up

Define the switch in /etc/vm.conf:

switch "lan" {
    interface bridge0
}

Activate it and start an already installed guest:

doas sh /etc/netstart bridge0
doas rcctl enable vmd
doas rcctl start vmd
doas vmctl reload
doas vmctl start -c -m 1G -d /var/vmm/images/obsd.img -n lan obsd

The guest obtains addressing from the LAN or uses a matching static configuration. To expose a single VLAN, create a vlanN interface with parent and vnetid settings and bridge that interface. vether0.<vlan> is not OpenBSD interface syntax.

Non-OpenBSD Guests #

FreeBSD #

Do not assume compatibility from a generic amd64 ISO. The official virtualization FAQ documents OpenBSD and Linux guests; this handbook does not provide a verified FreeBSD installation procedure.

Linux (Debian Example) #

Use media with serial-console support and a kernel supporting the provided virtual devices. Follow the current guest-specific installer instructions in the official virtualization FAQ and verify the image’s signature before booting it.

Windows (Unsupported Guest) #

vmm/vmd does not provide a supported Windows desktop guest procedure or graphical console. Use a host or hypervisor with documented Windows support.

VM Management #

For non-root access, configure doas(1) .

Troubleshooting #

• Check vmd logs: tail -f /var/log/daemon.
• Verify network interfaces: ifconfig -a.
• Confirm paths: /var/vmm/images/, /var/vmm/iso/.
• Check pf(4) rules for custom networking issues.