path: root/usr.sbin/vmd/vm.conf.5

.\" $OpenBSD: vm.conf.5,v 1.11 2016/10/20 19:44:09 jmc Exp $
.\"
.\" Copyright (c) 2015 Mike Larkin <mlarkin@openbsd.org>
.\" Copyright (c) 2015 Reyk Floeter <reyk@openbsd.org>
.\"
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.Dd $Mdocdate: October 20 2016 $
.Dt VM.CONF 5
.Os
.Sh NAME
.Nm vm.conf
.Nd virtual machine configuration
.Sh DESCRIPTION
.Nm
is the configuration file to configure the virtual machine monitor
(VMM) subsystem.
A VMM manages virtual machines (VMs) on a
.Ar host .
The VMM subsystem is responsible for creating, destroying, and
executing VMs.
.Sh SECTIONS
.Nm
is divided into three main sections:
.Bl -tag -width xxxx
.It Sy Macros
User-defined variables may be defined and used later, simplifying the
configuration file.
.It Sy VM Configuration
Configuration for each individual virtual machine.
.It Sy Switch Configuration
Configuration for virtual switches.
.El
.Pp
Within the sections,
the
.Ar bytes
argument can be specified with a human-readable scale,
using the format described in
.Xr scan_scaled 3 .
.Pp
The current line can be extended over multiple lines using a backslash
.Pq Sq \e .
Comments can be put anywhere in the file using a hash mark
.Pq Sq # ,
and extend to the end of the current line.
Care should be taken when commenting out multi-line text:
the comment is effective until the end of the entire block.
.Pp
Argument names not beginning with a letter, digit, underscore, or slash
must be quoted.
.Pp
Additional configuration files can be included with the
.Ic include
keyword, for example:
.Bd -literal -offset indent
include "/etc/vm1.example.com.conf"
.Ed
.Sh MACROS
Macros can be defined that will later be expanded in context.
Macro names must start with a letter, digit, or underscore,
and may contain any of those characters.
Macro names may not be reserved words (for example,
.Ic vm ,
.Ic memory ,
or
.Ic disk ) .
Macros are not expanded inside quotes.
.Pp
For example:
.Bd -literal -offset indent
ramdisk="/bsd.rd"
vm "vm1.example.com" {
	memory 512M
	kernel $ramdisk
}
.Ed
.Sh VM CONFIGURATION
Each
.Ic vm
section starts with a declaration of the virtual machine
.Ar name :
.Bl -tag -width Ds
.It Ic vm Ar name Brq ...
This name can be any string, and is typically a hostname.
.El
.Pp
Followed by a block of parameters that is enclosed in curly brackets:
.Bl -tag -width Ds
.It Cm enable
Automatically start the VM.
This is the default if neither
.Cm enable
nor
.Cm disable
is specified.
.It Cm disable
Do not start this VM.
.It Cm disk Ar path
Disk image file (may be specified multiple times to add multiple disk images).
.It Cm kernel Ar path
Kernel to load when booting the VM.
.It Cm memory Ar bytes
Memory size of the VM, in bytes, rounded to megabytes.
.It Cm interface Oo name Oc Op Brq ...
Network interface to add to the VM.
The optional
.Ar name
can be either
.Sq tap
to select the next available
.Xr tap 4
interface on the VM host side (the default) or
.Ar tapN
to select a specific one.
Valid options are:
.Bl -tag -width Ds
.It Cm group Ar group-name
Assign the interface to a specific interface
.Dq group .
For example, this can be used to write
.Xr pf.conf 5
rules for several VM interfaces in the same group.
The
.Ar group-name
must not end with a digit.
.It Cm lladdr Ar etheraddr
Change the link layer address (MAC address) of the interface on the
VM guest side.
If not specified, a randomized address will be assigned by
.Xr vmd 8 .
.It Cm switch Ar name
Set the virtual switch
by
.Ar name .
See the
.Sx SWITCH CONFIGURATION
section about virtual switches.
This option is ignored if a switch with a matching name cannot be found.
.It Cm up
Start the interface forwarding packets.
This is the default.
.It Cm down
Stop the interface from forwarding packets.
.El
.It Cm interfaces Ar count
Optional minimum number of network interfaces to add to the VM.
If the
.Ar count
is greater than the number of
.Ic interface
statements, additional default interfaces will be added.
.El
.Sh SWITCH CONFIGURATION
A virtual switch allows VMs to communicate with other network interfaces on the
host system via either
.Xr bridge 4
or
.Xr switch 4 .
The network interface for each virtual switch defined in
.Nm
is automatically created by
.Xr vmd 8 ,
but it is also possible to pre-configure switch interfaces using
.Xr hostname.if 5
or
.Xr ifconfig 8
(see the
.Sx BRIDGE
and
.Sx SWITCH
sections in
.Xr ifconfig 8
accordingly).
When a VM is started, virtual network interfaces which are assigned to a
virtual switch have their
.Xr tap 4
interface automatically added into the corresponding
.Xr bridge 4
or
.Xr switch 4
interface underlying the virtual switch.
.Pp
Virtual switches can be configured at any point in the configuration file.
Each
.Ic switch
section starts with a declaration of the virtual switch:
.Bl -tag -width Ds
.It Ic switch Ar name Brq ...
This name can be any string, and is typically a network name.
.El
.Pp
Followed by a block of parameters that is enclosed in curly brackets:
.Bl -tag -width Ds
.It Cm add Ar interface
Add
.Ar interface
as a member of the switch.
Any network interface can be added, typically as an uplink interface,
but it can be a member of at most one switch.
.It Cm enable
Automatically configure the switch.
This is the default if neither
.Cm enable
nor
.Cm disable
is specified.
.It Cm disable
Do not configure this switch.
.It Cm group Ar group-name
Assign each interface to a specific interface
.Dq group .
For example, this can be used to write
.Xr pf.conf 5
rules for several VM interfaces in the same group.
The
.Ar group-name
must not end with a digit.
.It Cm interface Ar name
Set the
.Xr switch 4
or
.Xr bridge 4
network interface of this switch.
If not specified,
.Ar bridge0
will be used where the interface unit will be incremented for each switch,
e.g.\&
.Ar bridge0 , bridge1 , ...
If the type is changed to
.Ar switch0 ,
it will be used for each following switch.
.It Cm up
Start the switch forwarding packets.
This is the default.
.It Cm down
Stop the switch from forwarding packets.
.El
.Sh EXAMPLES
Create a new VM with 512MB memory, 1 network interface connected to
.Dq uplink ,
one disk image
.Sq disk.img
and boot from kernel
.Sq /bsd :
.Bd -literal -offset indent
vm "vm2.example.com" {
	memory 512M
	disk "/var/vmm/vm2-disk.img"
	kernel "/bsd"
	interface { switch "uplink" }
}
.Ed
.Pp
Create the switch "uplink" with an additional physical network interface:
.Bd -literal -offset indent
switch "uplink" {
	add em0
}
.Ed
.Sh SEE ALSO
.Xr vmm 4 ,
.Xr vmctl 8 ,
.Xr vmd 8
.Sh HISTORY
The
.Nm
file format first appeared in
.Ox 5.9 .
.Sh AUTHORS
.An -nosplit
.An Mike Larkin Aq Mt mlarkin@openbsd.org
and
.An Reyk Floeter Aq Mt reyk@openbsd.org .