VIRSH(1) Virtualization Support VIRSH(1)
NAME
virsh - management user interface
SYNOPSIS
virsh <subcommand> [args]
DESCRIPTION
The virsh program is the main interface for managing virsh guest
domains. The program can be used to create, pause, and shutdown
domains. It can also be used to list current domains. Libvirt is a C
toolkit to interact with the virtualization capabilities of recent ver-
sions of Linux (and other OSes). It is free software available under
the GNU Lesser General Public License. Virtualization of the Linux
Operating System means the ability to run multiple instances of Operat-
ing Systems concurrently on a single hardware system where the basic
resources are driven by a Linux instance. The library aim at providing
long term stable C API initially for the Xen paravirtualization but
should be able to integrate other virtualization mechanisms, it cur-
rently also support QEmu and KVM.
The basic structure of most virsh usage is:
virsh <command> <domain-id> [OPTIONS]
Where command is one of the commands listed below, domain-id is the
numeric domain id, or the domain name (which will be internally trans-
lated to domain id), and OPTIONS are command specific options. There
are a few exceptions to this rule in the cases where the command in
question acts on all domains, the entire machine, or directly on the
xen hypervisor. Those exceptions will be clear for each of those com-
mands.
The virsh program can be used either to run one command at a time by
giving the command as an argument on the command line, or as a shell if
no command is given in the command line, it will then start a minimal
interpreter waiting for your commands and the quit command will then
exit the program.
NOTES
All virsh operations rely upon the libvirt library. For any virsh com-
mands to run xend/qemu, or what ever virtual library that libvirt sup-
ports. For this reason you should start xend/qemu as a service when
your system first boots using xen/qemu. This can usually be done using
the command service start libvirtd .
Most virsh commands require root privileges to run due to the communi-
cations channels used to talk to the hypervisor. Running as non root
will return an error.
Most virsh commands act asynchronously, so just because the virsh pro-
gram returned, doesn’t mean the action is complete. This is important,
as many operations on domains, like create and shutdown, can take con-
siderable time (30 seconds or more) to bring the machine into a fully
compliant state. If you want to know when one of these actions has
finished you must poll through virsh list periodically.
GENERIC COMMANDS
The following commands are generic i.e. not specific to a domain.
help optional command
This prints a small synopsis about all commands available for virsh
help command will print out a detailed help message on that
command.
quit
quit this interactive terminal
version
Will print out the major version info about what this built from.
Example
virsh version
Compiled against library: libvir 0.0.6
Using library: libvir 0.0.6
Using API: Xen 3.0.0
Running hypervisor: Xen 3.0.0
connect URI optional --readonly
(Re)-Connect to the hypervisor. This is a build-in command after
shell start up, and usually get an URI parameter specifying how to
connect to the hypervisor. The documentation page at <http://lib-
virt.org/uri.html> list the values supported but the most common
are:
xen:///
this is used to connect to the local Xen hypervisor, this is
the default
qemu:///system
allow to connect locally as root to the daemon supervizing QEmu
and KVM domains
qemu:///session
allow to connect locally as a normal user to the his own set of
QEmu and KVM domains
For remote access see the documentation page on how to make URIs.
The --readonly option allows for read-only connection
nodeinfo
Returns basic information about the node, like number and type of
CPU, and size of the physical memory.
capabilities
Print an XML document describing the capabilities of the hypervisor
we are currently connected to. This includes a section on the host
capabilities in terms of CPU and features, and a set of description
for each kind of guest which can be virtualized. For a more com-
plete description see:
<http://libvirt.org/format.html#Capa1> The XML also show the NUMA
topology informations if available.
list
Prints information about one or more domains. If no domains are
specified it prints out information about all domains.
An example format for the list is as follows:
virsh list
Id Name State
----------------------------------
0 Domain-0 running
2 fedora paused
Name is the name of the domain. ID the domain numeric id.
State is the run state (see below).
freecell optional cellno
Prints the available amount of memory on the machine or within a
NUMA cell if cellno is provided.
STATES
The State field lists 6 states for a Xen Domain, and which ones
the current Domain is in.
r - running
The domain is currently running on a CPU
b - blocked
The domain is blocked, and not running or runnable. This can
be caused because the domain is waiting on IO (a traditional
wait state) or has gone to sleep because there was nothing else
for it to do.
p - paused
The domain has been paused, usually occurring through the
administrator running xm pause. When in a paused state the
domain will still consume allocated resources like memory, but
will not be eligible for scheduling by the Xen hypervisor.
s - shutdown
The domain is in the process of shutting down, i.e. the guest
operating system has been notified and should be in the process
of stopping its operations gracefully.
c - crashed
The domain has crashed, which is always a violent ending. Usu-
ally this state can only occur if the domain has been config-
ured not to restart on crash. See xmdomain.cfg for more info.
d - dying
The domain is in process of dying, but hasn’t completely shut-
down or crashed.
DOMAIN COMMANDS
The following commands manipulate domains directly, as stated previ-
ously most commands take domain-id as the first parameter. The domain-
id can be specified as an short integer, a name or a full UUID.
autostart optional --disable domain-id
Configure a domain to be automatically started at boot.
The option --disable disable autostarting.
console domain-id
Connect the virtual serial console for the guest.
create FILE
Create a domain from an XML <file> an easy way to create one if you
have a pre-existing xen guest created via xm create <XMLFILE>.
Example
virsh dumpxml <domain-id> > file.
define FILE
Define a domain from an XML <file>. The domain definitions is reg-
istered but not started.
destroy domain-id
Immediately terminate the domain domain-id. This doesn’t give the
domain OS any chance to react, and it the equivalent of ripping the
power cord out on a physical machine. In most cases you will want
to use the shutdown command instead.
dominfo domain-id
Returns basic information about the domain.
domuuid domain-name-or-id
Convert a domain name or id to domain UUID
domid domain-name
Converts a domain name to a domain id using xend’s internal map-
ping.
dominfo domain-id
Returns basic information about the domain.
domname domain-id
convert a domain Id to domain name
domstate domain-id
Returns state about a running domain.
dumpxml domain-id
Output the domain informations as an XML dump to stdout, this for-
mat can be used by the create command.
reboot domain-id
Reboot a domain. This acts just as if the domain had the reboot
command run from the console. The command returns as soon as it
has executed the reboot action, which may be significantly before
the domain actually reboots.
For xen vm the behavior of what happens to a domain when it reboots
is set by the on_reboot parameter of the xmdomain.cfg file when the
domain was created.
restore state-file
Restores a domain from an virsh save state file. See save for more
info.
save domain-id state-file
Saves a running domain to a state file so that it can be restored
later. Once saved, the domain will no longer be running on the
system, thus the memory allocated for the domain will be free for
other domains to use. virsh restore restores from this state file.
This is roughly equivalent to doing a hibernate on a running com-
puter, with all the same limitations. Open network connections may
be severed upon restore, as TCP timeouts may have expired.
setmem domain-id kilobytes
Change the current memory allocation in the guest domain. This
should take effect immediately. The memory limit is specified in
kilobytes.
setmaxmem domain-id kilobytes
Change the maximum memory allocation limit in the guest domain.
This should not change the current memory use. The memory limit is
specified in kilobytes.
setvcpus domain-id count
Change the number of virtual CPUs active in the guest domain. Note
that count may be limited by host, hypervisor or limit coming from
the original description of domain.
shutdown domain-id
Gracefully shuts down a domain. This coordinates with the domain
OS to perform graceful shutdown, so there is no guarantee that it
will succeed, and may take a variable length of time depending on
what services must be shutdown in the domain.
For a xen guest vm the behavior of what happens to a domain when it
reboots is set by the on_shutdown parameter of the xmdomain.cfg
file when the domain was created.
suspend domain-id
Suspend a running domain. It is kept in memory but won’t be sched-
uled anymore.
resume domain-id
Moves a domain out of the suspended state. This will allow a pre-
viously suspended domain to now be eligible for scheduling by the
underlying hypervisor.
ttyconsole domain-id
Output the device used for the TTY console of the domain. If the
information is not available the processes will provide an exit
code of 1.
undefine domain-id
Undefine the configuration for an inactive domain. Since it’s not
running the domain name or UUId must be used as the domain-id.
vcpuinfo domain-id
Returns basic information about the domain virtual CPUs, like the
number of vCPUs, the running time, the affinity to physical proces-
sors.
vcpupin domain-id vcpu cpulist
Pin domain VCPUs to host physical CPUs. The vcpu number must be
provided and cpulist is a comma separated list of physical CPU num-
bers.
vncdisplay domain-id
Output the IP address and port number for the VNC display. If the
information is not available the processes will provide an exit
code of 1.
DEVICES COMMANDS
The following commands manipulate devices associated to domains. The
domain-id can be specified as an short integer, a name or a full UUID.
To better understand the values allowed as options for the command
reading the documentation at <http://libvirt.org/format.html> on the
format of the device sections to get the most accurate set of accepted
values.
attach-device domain-id FILE
Attach a device to the domain, using a device definition in an XML
file. See the documentation to learn about libvirt XML format for
a device.
attach-disk domain-id source target optional --driver driver --sub-
driver subdriver --type type --mode mode
Attach a new disk device to the domain. source and target are
paths for the files and devices. driver can be file, tap or phy
depending on the kind of access. type can indicate cdrom or floppy
as alternative to the disk default. mode can specify the two spe-
cific mode readonly or shareable.
attach-interface domain-id type source optional --target target --mac
mac --script script
Attach a new network interface to the domain. type can be either
network to indicate a physical network device or bridge to indicate
a bridge to a device. source indicates the source device. target
allows to indicate the target device in the guest. mac allows to
specify the MAC address of the network interface. script allows to
specify a path to a script handling a bridge instead of the default
one.
detach-device domain-id FILE
Detach a device from the domain, takes the same kind of XML
descriptions as command attach-device.
detach-disk domain-id target
Detach a disk device from a domain. The target is the device as
seen from the domain.
detach-interface domain-id type optional --mac mac
Detach a network interface from a domain. type can be either net-
work to indicate a physical network device or bridge to indicate a
bridge to a device. It is recommended to use the mac option to
distinguish between the interfaces if more than one are present on
the domain.
VIRTUAL NETWORKS COMMANDS
The following commands manipulate networks. Libvirt has the capability
to define virtual networks which can then be used by domains and linked
to actual network devices. For more detailed informations about this
feature see the documentation at <http://libvirt.org/format.html#Net1>
. A lot of the command for virtual networks are similar to the one used
for domains, but the way to name a virtual network is either by its
name or UUID.
net-autostart network optional --disable
Configure a virtual network to be automatically started at boot.
The --disable option disable autostarting.
net-create file
Create a virtual network from an XML file, see the documentation to
get a description of the XML network format used by libvirt.
net-define file
Define a virtual network from an XML file, the network is just
defined but not instantiated.
net-destroy network
Destroy a given virtual network specified by its name or UUID. This
takes effect immediately.
net-dumpxml network
Output the virtual network information as an XML dump to stdout.
net-list optional --inactive or --all
Returns the list of active networks, if --all is specified this
will also include defined but inactive networks, if --inactive is
specified only the inactive ones will be listed.
net-name network-UUID
Convert a network UUID to network name.
net-start network
Start a (previously defined) inactive network.
net-undefine network
Undefine the configuration for an inactive network.
net-uuid network-name
Convert a network name to network UUID.
ENVIRONMENT
VIRSH_DEFAULT_CONNECT_URI
The hypervisor to connect to by default. Set this to a URI, in the
same format as accepted by the connect option.
SEE ALSO
xm(1), xmdomain.cfg(5), xentop(1) , <http://www.libvirt.org/>
AUTHOR
Andrew Puch <apuch @ redhat.com>
Daniel Veillard <veillard @ redhat.com>
Based on the xm man paged by
Sean Dague <sean at dague dot net>
Daniel Stekloff <dsteklof at us dot ibm dot com>
BUGS
Bugs can be view on the RedHat buzilla page under the libvirt
<https://bugzilla.redhat.com/>
<https://bugzilla.redhat.com/bugzilla/buglist.cgi?prod-
uct=Fedora+Core&component=libvirt&bug_status=NEW&bug_sta-
tus=ASSIGNED&bug_status=REOPENED&bug_status=MODI-
FIED&short_desc_type=allwordssubstr&short_desc=&long_desc_type=all-
wordssubstr>
perl v5.8.8 2007-09-28 VIRSH(1)
