| VMCTL(8) | System Manager's Manual | VMCTL(8) |
vmctl — control
the virtual machine daemon
vmctl |
[-v] command
[arg ...] |
The vmctl utility is used to control the
virtual machine monitor (VMM) subsystem. A VMM manages virtual machines
(VMs) on a host. The VMM subsystem is responsible for creating, destroying,
and executing VMs.
The -v option enables verbose mode. Within
the commands, the size argument can be specified with
a human-readable scale, using the format described in
scan_scaled(3). The
id argument can be either a numeric, non-zero
identifier or alternatively the name of a virtual machine.
The name argument can only consist of alphanumeric characters, as well as '.', '-', and '_', and must start with a letter.
The disk argument is used by commands that take a path to a disk image file. It may be prefixed with a format prefix (raw:disk or qcow2:disk) in order to specify the disk image format. If left unspecified, the format defaults to ‘raw’ if it cannot be derived automatically.
The commands are as follows:
console
idcreate
[-b base |
-i disk]
[-s size]
disk-b
base-i
disk-b
base.-s
size-b option is specified,
the size must match the size of the base image.
For the -i option, the size cannot be smaller
than the input disk size. The size can be omitted with the
-b and -i options and
will be obtained from the base or input image respectively.load
filenamelog
brief |
verbosepause
idreceive
namereloadreset
[all | switches |
vms]switches, or reset
and terminate all vms.send
idIn order to move a VM from one host to another, disk files must be synced between the send and the receive processes and must be located under the same path.
show
[id]status command.start
[-cL]
[-B device]
[-b path]
[-d disk]
[-i count]
[-m size]
[-n switch]
[-r path]
[-t name] id
| name-B
deviceCurrently net is only supported when
booting a kernel using the -b flag while
disk and cdrom only work
with VMs booted using BIOS.
-b
path-c-d
disk-i
count-L-L option.-m
size-n
switch-r
path-t
namestatus
[id]stop
[-fw] [-a |
id]-a). By default, a graceful
shutdown will be attempted if the VM supports the
vmmci(4) device.
The following options can be specified when stopping a VM:
unpause
idwait
idIf the -i, -L, or
-n options are specified during VM startup, a
corresponding number of host-side
tap(4) interfaces will be
allocated and mapped to the
vio(4) interfaces inside the
guest VM. This tap/vio interface mapping allows guest network traffic to be
manipulated by the host. Any valid host-side interface configuration may be
performed on these tap interfaces, such as bridging (via
veb(4)), or using
pf(4) nat-to rules to create
private or host-side NATed networks, as desired. For each
tap(4) network interface on the
host, vmd(8) will set the
interface's description to allow easy identification of the corresponding VM
by ID, interface number, and name:
# ifconfig tap0 tap0: flags=8842<BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500 lladdr fe:e1:ba:d8:50:d1 description: vm1-if0-myvm index 15 priority 0 llprio 3 groups: tap status: active
Local interfaces can be used to easily configure VM networking without needing to manually assign network addresses. A local interface is added to a VM using the -L option to the 'vmctl start' command and results in the addition of a vio(4) interface inside the VM and a corresponding tap(4) interface on the host. When using local interfaces, vmd(8) will provide DHCP services to the guest VM and offer addresses selected from the 100.64.0.0/10 IPv4 range. From within the 100.64.0.0/10 range, vmd(8) allocates a pair of addresses for the guest-side vio(4) and host-side tap(4) interfaces as follows:
For the first local interface:
For the second and subsequent local interface(s):
Multiple -L options can be provided to the 'vmctl start' command, if more than one interface is desired. Local interfaces are assigned to the VM before any other interfaces specified with the -i option (thus, local interfaces, if requested, are numbered starting at vio0 inside the guest VM).
If NAT is desired, the net.inet.ip.forwarding sysctl(8) must also be set to 1.
When using local interfaces, the DHCP configuration offered to the guest VM specifies the address of the corresponding host tap(4) interface as both the default route and the (sole) nameserver. Guest VM traffic can optionally be NATed through the host with an entry in the host machine's /etc/pf.conf similar to the following:
pass out on egress from 100.64.0.0/10 to any nat-to (egress)
If desired, DNS queries originating from guest VMs can be redirected to a different DNS server with an entry in the host machine's /etc/pf.conf similar to the following:
pass in proto { udp tcp } from 100.64.0.0/10 to any port domain \
rdr-to $dns_server port domain
The vmctl utility exits 0 on
success, and >0 if an error occurs. vmctl
may fail due to one of the following reasons:
Create a 4.5 Gigabyte disk image, disk.img:
$ vmctl create -s 4.5G disk.img
Convert a disk image from the ‘raw’ format to ‘qcow2’:
$ vmctl create -i disk.img disk.qcow2
Create a new VM with 1GB memory, one network interface, one disk image ('disk.img') and boot from kernel '/bsd':
# vmctl start -m 1G -i 1 -b /bsd -d disk.img "myvm"
Start a new VM instance with the name 'myvm' from a pre-configured VM 'openbsd.4G':
# vmctl start -t "openbsd.4G" -d mydisk.img "myvm"
Terminate VM number 1:
# vmctl stop 1
pf(4), tap(4), veb(4), vio(4), vmm(4), vm.conf(5), rc.conf(8), sysctl(8), vmd(8)
The vmctl command first appeared in
OpenBSD 5.9.
Mike Larkin <mlarkin@openbsd.org> and Reyk Floeter <reyk@openbsd.org>.
| March 1, 2021 | OpenBSD-7.0 |