# Bhyve driver

- Connections to the Bhyve driver
- Example guest domain XML configurations
- Guest usage / management
  - Connecting to a guest console

Bhyve is a FreeBSD hypervisor. It first appeared in FreeBSD 10.0. However, it's recommended to keep tracking FreeBSD 10-STABLE to make sure all new features of bhyve are supported. In order to enable bhyve on your FreeBSD host, you'll need to load the `vmm` kernel module. Additionally, `if_tap` and `if_bridge` modules should be loaded for networking support.

Additional information on bhyve could be obtained on bhyve.org.

## Connections to the Bhyve driver

The libvirt bhyve driver is a single-instance privileged driver. Some sample connection URIs are:

    bhyve:///system                     (local access)
    bhyve+unix:///system                (local access)
    bhyve+ssh://root@example.com/system (remote access, SSH tunnelled)

## Example guest domain XML configurations

### Example config

The bhyve driver in libvirt is in its early stage and under active development. So it supports only limited number of features bhyve provides. All the supported features could be found in this sample domain XML.

A limitation that is not obvious from this sample domain XML is that currently only a single network and a single disk device are supported for each domain (as PCI slot allocation code in libvirt bhyve driver is yet to be implemented).

    <domain type='bhyve'>
      <name>bhyve</name>
      <uuid>df3be7e7-a104-11e3-aeb0-50e5492bd3dc</uuid>
        <memory>219136</memory>
        <currentMemory>219136</currentMemory>
        <vcpu>1</vcpu>
        <os>
           <type>hvm</type>
        </os>
        <features>
          <apic/>
          <acpi/>
        </features>
        <clock offset='utc'/>
        <on_poweroff>destroy</on_poweroff>
        <on_reboot>restart</on_reboot>
        <on_crash>destroy</on_crash>
        <devices>
          <disk type='file'>
            <driver name='file' type='raw'/>
            <source file='/path/to/bhyve_freebsd.img'/>
            <target dev='hda' bus='sata'/>
          </disk>
          <interface type='bridge'>
            <model type='virtio'/>
            <source bridge="virbr0"/>
          </interface>
        </devices>
    </domain>

## Guest usage / management

### Connecting to a guest console

Guest console connection is supported through the `nmdm` device. It could be enabled by adding the following to the domain XML (Since 1.2.4):

      ...
      <devices>
        <serial type="nmdm">
          <source master="/dev/nmdm0A" slave="/dev/nmdm0B"/>
        </serial>
      </devices>
      ...

Then `virsh console` command can be used to connect to the text console of a guest.

NB: Some versions of bhyve have a bug that prevents guests from booting until the console is opened by a client. This bug was fixed in FreeBSD r262884. If an older version is used, one either has to open a console manually with `virsh console` to let a guest boot or start a guest using:

    start --console domname