virsh.pod

=head1 NAME

virsh - management user interface

=head1 SYNOPSIS

virsh <subcommand> [args]

=head1 DESCRIPTION

The B<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
versions 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
Operating Systems concurrently on a single hardware system where the
basic resources are driven by a Linux instance. The library aims at
providing a long term stable C API.  It currently supports Xen, QEmu,
KVM, LXC, OpenVZ, VirtualBox, OpenNebula, and VMware ESX.

The basic structure of most virsh usage is:

  virsh <command> <domain-id> [OPTIONS]

Where I<command> is one of the commands listed below, I<domain-id>
is the numeric domain id, or the domain name (which will be internally
translated to domain id), and I<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 commands.

The B<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 B<quit> command will then exit
the program.

=head1 NOTES

Most B<virsh> operations rely upon the libvirt library being able to
connect to an already running libvirtd service.  This can usually be
done using the command B<service libvirtd start>.

Most B<virsh> commands require root privileges to run due to the
communications channels used to talk to the hypervisor.  Running as
non root will return an error.

Most B<virsh> commands act synchronously, except maybe shutdown,
setvcpus and setmem. In those cases the fact that the B<virsh>
program returned, may not mean the action is complete and you
must poll periodically to detect that the guest completed the
operation.

=head1 GENERIC COMMANDS

The following commands are generic i.e. not specific to a domain.

=over 4

=item B<help> optional I<command>

This prints a small synopsis about all commands available for B<virsh>
B<help> I<command> will print out a detailed help message on that command.

=item B<quit>, B<exit>

quit this interactive terminal

=item B<version>

Will print out the major version info about what this built from.

=over 4

B<Example>

B<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

=back

=item B<cd> I<directory> optional

Will change current directory to I<directory>.  The default directory
for the B<cd> command is the home directory or, if there is no I<HOME>
variable in the environment, the root directory.

This command is only available in interactive mode.

=item B<pwd>

Will print the current directory.

=item B<connect> I<URI> optional I<--readonly>

(Re)-Connect to the hypervisor. When the shell is first started, this
is automatically run with the I<URI> parameter requested by the C<-c>
option on the command line. The I<URI> parameter specifies how to
connect to the hypervisor. The documentation page at
L<http://libvirt.org/uri.html> list the values supported, but the most
common are:

=over 4

=item xen:///

this is used to connect to the local Xen hypervisor, this is the default

=item qemu:///system

connect locally as root to the daemon supervising QEmu and KVM domains

=item qemu:///session

connect locally as a normal user to his own set of QEmu and KVM domains

=item lxc:///

connect to a local linux container

=back

For remote access see the documentation page on how to make URIs.
The I<--readonly> option allows for read-only connection

=item B<uri>

Prints the hypervisor canonical URI, can be useful in shell mode.

=item B<hostname>

Print the hypervisor hostname.

=item B<nodeinfo>

Returns basic information about the node, like number and type of CPU,
and size of the physical memory.

=item B<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 complete
description see:
  L<http://libvirt.org/formatcaps.html>
The XML also show the NUMA topology information if available.

=item B<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:

B<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).

B<STATES>

The State field lists 6 states for a domain, and which ones the
current domain is in.

=over 4

=item B<running>

The domain is currently running on a CPU

=item B<idle>

The domain is idle, 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.

=item B<paused>

The domain has been paused, usually occurring through the administrator
running B<virsh suspend>.  When in a paused state the domain will still
consume allocated resources like memory, but will not be eligible for
scheduling by the hypervisor.

=item B<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.

=item B<crashed>

The domain has crashed, which is always a violent ending.  Usually
this state can only occur if the domain has been configured not to
restart on crash.

=item B<dying>

The domain is in process of dying, but hasn't completely shutdown or
crashed.

=back

=item B<freecell> optional I<cellno>

Prints the available amount of memory on the machine or within a
NUMA cell if I<cellno> is provided.

=item B<cpu-baseline> I<FILE>

Compute baseline CPU which will be supported by all host CPUs given in <file>.
The list of host CPUs is built by extracting all <cpu> elements from the
<file>. Thus, the <file> can contain either a set of <cpu> elements separated
by new lines or even a set of complete <capabilities> elements printed by
B<capabilities> command.

=item B<cpu-compare> I<FILE>

Compare CPU definition from XML <file> with host CPU. The XML <file> may
contain either host or guest CPU definition. The host CPU definition is the
<cpu> element and its contents as printed by B<capabilities> command. The
guest CPU definition is the <cpu> element and its contents from domain XML
definition. For more information on guest CPU definition see:
L<http://libvirt.org/formatdomain.html#elementsCPU>

=back

=head1 DOMAIN COMMANDS

The following commands manipulate domains directly, as stated
previously most commands take domain-id as the first parameter. The
I<domain-id> can be specified as an short integer, a name or a full UUID.

=over 4

=item B<autostart> optional I<--disable> I<domain-id>

Configure a domain to be automatically started at boot.

The option I<--disable> disables autostarting.

=item B<console> I<domain-id>

Connect the virtual serial console for the guest.

=item B<create> I<FILE>

Create a domain from an XML <file>. An easy way to create the XML
<file> is to use the B<dumpxml> command to obtain the definition of a
pre-existing guest.

B<Example>

virsh dumpxml <domain-id> > domain.xml
edit domain.xml
virsh create < domain.xml

=item B<define> I<FILE>

Define a domain from an XML <file>. The domain definitions is registered
but not started.

=item B<destroy> I<domain-id>

Immediately terminate the domain domain-id.  This doesn't give the domain
OS any chance to react, and it's the equivalent of ripping the power
cord out on a physical machine.  In most cases you will want to use
the B<shutdown> command instead.

=item B<domblkstat> I<domain> I<block-device>

Get device block stats for a running domain.

=item B<domifstat> I<domain> I<interface-device>

Get network interface stats for a running domain.

=item B<dommemstat> I<domain>

Get memory stats for a running domain.

=item B<dominfo> I<domain-id>

Returns basic information about the domain.

=item B<domuuid> I<domain-name-or-id>

Convert a domain name or id to domain UUID

=item B<domid> I<domain-name-or-uuid>

Convert a domain name (or UUID) to a domain id

=item B<domjobabort> I<domain-id-or-uuid>

Abort the currently running domain job.

=item B<domjobinfo> I<domain-id-or-uuid>

Returns information about jobs running on a domain.

=item B<domname> I<domain-id-or-uuid>

Convert a domain Id (or UUID) to domain name

=item B<domstate> I<domain-id>

Returns state about a running domain.

=item B<domxml-from-native> I<format> I<config>

Convert the file I<config> in the native guest configuration format
named by I<format> to a domain XML format.

=item B<domxml-to-native> I<format> I<xml>

Convert the file I<xml> in domain XML format to the native guest
configuration format named by I<format>.

=item B<dump> I<domain-id> I<corefilepath>

Dumps the core of a domain to a file for analysis.

=item B<dumpxml> I<domain-id> optional I<--inactive> I<--security-info> I<--update-cpu>

Output the domain information as an XML dump to stdout, this format can be used
by the B<create> command. Additional options affecting the XML dump may be
used. I<--inactive> tells virsh to dump domain configuration that will be used
on next start of the domain as opposed to the current domain configuration.
Using I<--security-info> security sensitive information will also be included
in the XML dump. I<--update-cpu> updates domain CPU requirements according to
host CPU.

=item B<edit> I<domain-id>

Edit the XML configuration file for a domain.

This is equivalent to:

 virsh dumpxml domain > domain.xml
 edit domain.xml
 virsh define domain.xml

except that it does some error checking.

The editor used can be supplied by the C<$VISUAL> or C<$EDITOR> environment
variables, and defaults to C<vi>.

=item B<managedsave> I<domain-id>

Ask libvirt to save a running domain state in a place managed by libvirt.
If libvirt is asked to restart the domain later on it will resume it from
the saved domain state (and the state is discarded).

=item B<migrate> optional I<--live> I<--suspend> I<domain-id> I<desturi> I<migrateuri>

Migrate domain to another host.  Add --live for live migration; --suspend
leaves the domain paused on the destination host. The I<desturi> is the
connection URI of the destination host, and I<migrateuri> is the
migration URI, which usually can be omitted.

=item B<migrate-setmaxdowntime> I<domain-id> I<downtime>

Set maximum tolerable downtime for a domain which is being live-migrated to
another host.  The I<downtime> is a number of milliseconds the guest is allowed
to be down at the end of live migration.

=item B<reboot> I<domain-id>

Reboot a domain.  This acts just as if the domain had the B<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.

The exact behavior of a domain when it reboots is set by the
I<on_reboot> parameter in the domain's XML definition.

=item B<restore> I<state-file>

Restores a domain from an B<virsh save> state file.  See I<save> for more info.

=item B<save> I<domain-id> I<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.  B<virsh restore> restores from this state file.

This is roughly equivalent to doing a hibernate on a running computer,
with all the same limitations.  Open network connections may be
severed upon restore, as TCP timeouts may have expired.

=item B<schedinfo> optional I<--set> B<parameter=value> I<domain-id>

=item B<schedinfo> optional I<--weight> B<number> optional I<--cap> B<number> I<domain-id>

Allows you to show (and set) the domain scheduler parameters. The parameters available for each hypervisor are:

LXC, QEMU/KVM (posix scheduler): cpu_shares

Xen (credit scheduler): weight, cap

ESX (allocation scheduler): reservation, limit, shares

B<Note>: The cpu_shares parameter has a valid value range of 0-262144.

B<Note>: The weight and cap parameters are defined only for the
XEN_CREDIT scheduler and are now I<DEPRECATED>.

=item B<setmem> I<domain-id> B<kilobytes>

Change the current memory allocation in the guest domain. This should take
effect immediately. The memory limit is specified in
kilobytes.

For Xen, you can only adjust the memory of a running domain if the
domain is paravirtualized or running the PV balloon driver.

=item B<setmaxmem> I<domain-id> B<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.

=item B<setvcpus> I<domain-id> I<count>

Change the number of virtual CPUs active in the guest domain. Note that
I<count> may be limited by host, hypervisor or limit coming from the
original description of domain.

For Xen, you can only adjust the virtual CPUs of a running domain if
the domain is paravirtualized.

=item B<shutdown> I<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.

The exact behavior of a domain when it shuts down is set by the
I<on_shutdown> parameter in the domain's XML definition.

=item B<start> I<domain-name>

Start a (previously defined) inactive domain.

=item B<suspend> I<domain-id>

Suspend a running domain. It is kept in memory but won't be scheduled
anymore.

=item B<resume> I<domain-id>

Moves a domain out of the suspended state.  This will allow a previously
suspended domain to now be eligible for scheduling by the underlying
hypervisor.

=item B<ttyconsole> I<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.

=item B<undefine> I<domain-id>

Undefine the configuration for an inactive domain. Since it's not running
the domain name or UUId must be used as the I<domain-id>.

=item B<vcpuinfo> I<domain-id>

Returns basic information about the domain virtual CPUs, like the number of
vCPUs, the running time, the affinity to physical processors.

=item B<vcpupin> I<domain-id> I<vcpu> I<cpulist>

Pin domain VCPUs to host physical CPUs. The I<vcpu> number must be provided
and I<cpulist> is a comma separated list of physical CPU numbers.

=item B<vncdisplay> I<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.

=back

=head1 DEVICE 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 L<http://libvirt.org/formatdomain.html> on the
format of the device sections to get the most accurate set of accepted values.

=over 4

=item B<attach-device> I<domain-id> I<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.

=item B<attach-disk> I<domain-id> I<source> I<target> optional I<--driver driver> I<--subdriver subdriver> I<--type type> I<--mode mode>

Attach a new disk device to the domain.
I<source> and I<target> are paths for the files and devices.
I<driver> can be I<file>, I<tap> or I<phy> depending on the kind of access.
I<type> can indicate I<cdrom> or I<floppy> as alternative to the disk default.
I<mode> can specify the two specific mode I<readonly> or I<shareable>.

=item B<attach-interface> I<domain-id> I<type> I<source> optional I<--target target> I<--mac mac> I<--script script>

Attach a new network interface to the domain.
I<type> can be either I<network> to indicate a physical network device or I<bridge> to indicate a bridge to a device.
I<source> indicates the source device.
I<target> allows to indicate the target device in the guest.
I<mac> allows to specify the MAC address of the network interface.
I<script> allows to specify a path to a script handling a bridge instead of
the default one.

=item B<detach-device> I<domain-id> I<FILE>

Detach a device from the domain, takes the same kind of XML descriptions
as command B<attach-device>.

=item B<detach-disk> I<domain-id> I<target>

Detach a disk device from a domain. The I<target> is the device as seen
from the domain.

=item B<detach-interface> I<domain-id> I<type> optional I<--mac mac>

Detach a network interface from a domain.
I<type> can be either I<network> to indicate a physical network device or I<bridge> to indicate a bridge to a device.
It is recommended to use the I<mac> option to distinguish between the interfaces
if more than one are present on the domain.

=back

=head1 VIRTUAL NETWORK 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 information about this feature
see the documentation at L<http://libvirt.org/formatnetwork.html> . 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.

=over 4

=item B<net-autostart> I<network> optional I<--disable>

Configure a virtual network to be automatically started at boot.
The I<--disable> option disable autostarting.

=item B<net-create> I<file>

Create a virtual network from an XML I<file>, see the documentation to get
a description of the XML network format used by libvirt.

=item B<net-define> I<file>

Define a virtual network from an XML I<file>, the network is just defined but
not instantiated.

=item B<net-destroy> I<network>

Destroy a given virtual network specified by its name or UUID. This takes
effect immediately.

=item B<net-dumpxml> I<network>

Output the virtual network information as an XML dump to stdout.

=item B<net-edit> I<network>

Edit the XML configuration file for a network.

This is equivalent to:

 virsh net-dumpxml network > network.xml
 edit network.xml
 virsh net-define network.xml

except that it does some error checking.

The editor used can be supplied by the C<$VISUAL> or C<$EDITOR> environment
variables, and defaults to C<vi>.

=item B<net-list> optional I<--inactive> or I<--all>

Returns the list of active networks, if I<--all> is specified this will also
include defined but inactive networks, if I<--inactive> is specified only the
inactive ones will be listed.

=item B<net-name> I<network-UUID>

Convert a network UUID to network name.

=item B<net-start> I<network>

Start a (previously defined) inactive network.

=item B<net-undefine> I<network>

Undefine the configuration for an inactive network.

=item B<net-uuid> I<network-name>

Convert a network name to network UUID.

=back

=head1 STORAGE POOL COMMANDS

The following commands manipulate storage pools. Libvirt has the
capability to manage various storage solutions, including files, raw
partitions, and domain-specific formats, used to provide the storage
volumes visible as devices within virtual machines. For more detailed
information about this feature, see the documentation at
L<http://libvirt.org/formatstorage.html> . A lot of the commands for
pools are similar to the ones used for domains.

=over 4

=item B<find-storage-pool-sources> I<type> optional I<srcSpec>

Returns XML describing all storage pools of a given I<type> that could
be found.  If I<srcSpec> is provided, it is a file that contains XML
to further restrict the query for pools.

=item B<find-storage-pool-sources> I<type> optional I<host> I<port>

Returns XML describing all storage pools of a given I<type> that could
be found.  If I<host> and I<port> are provided, they control where the
query is performed.

=item B<pool-autostart> I<pool-or-uuid> optional I<--disable>

Configure whether I<pool> should automatically start at boot.

=item B<pool-build> I<pool-or-uuid>

Build a given pool.

=item B<pool-create> I<file>

Create and start a pool object from the XML I<file>.

=item B<pool-create-as> I<name> I<--print-xml> I<type> optional I<source-host>
I<source-path> I<source-dev> I<source-name> <target>

Create and start a pool object I<name> from the raw parameters.  If
I<--print-xml> is specified, then print the XML of the pool object
without creating the pool.  Otherwise, the pool has the specified
I<type>.

=item B<pool-define> I<file>

Create, but do not start, a pool object from the XML I<file>.

=item B<pool-define-as> I<name> I<--print-xml> I<type> optional I<source-host>
I<source-path> I<source-dev> I<source-name> <target>

Create, but do not start, a pool object I<name> from the raw parameters.  If
I<--print-xml> is specified, then print the XML of the pool object
without defining the pool.  Otherwise, the pool has the specified
I<type>.

=item B<pool-destroy> I<pool-or-uuid>

Destroy a given I<pool> object. Libvirt will no longer manage the
storage described by the pool object, but the raw data contained in
the pool is not changed, and can be later recovered with
B<pool-create>.

=item B<pool-delete> I<pool-or-uuid>

Destroy the resources used by a given I<pool> object. This operation
is non-recoverable.  The I<pool> object will still exist after this
command.

=item B<pool-dumpxml> I<pool-or-uuid>

Returns the XML information about the I<pool> object.

=item B<pool-edit> I<pool-or-uuid>

Edit the XML configuration file for a storage pool.

This is equivalent to:

 virsh pool-dumpxml pool > pool.xml
 edit pool.xml
 virsh pool-define pool.xml

except that it does some error checking.

The editor used can be supplied by the C<$VISUAL> or C<$EDITOR> environment
variables, and defaults to C<vi>.

=item B<pool-info> I<pool-or-uuid>

Returns basic information about the I<pool> object.

=item B<pool-list> optional I<--inactive> I<--all>

List pool objects known to libvirt.  By default, only pools in use by
active domains are listed; I<--inactive> lists just the inactive
pools, and I<--all> lists all pools.

=item B<pool-name> I<uuid>

Convert the I<uuid> to a pool name.

=item B<pool-refresh> I<pool-or-uuid>

Refresh the list of volumes contained in I<pool>.

=item B<pool-start> I<pool-or-uuid>

Start the storage I<pool>, which is previously defined but inactive.

=item B<pool-undefine> I<pool-or-uuid>

Undefine the configuration for an inactive I<pool>.

=item B<pool-uuid> I<pool>

Returns the UUID of the named I<pool>.

=head1 SECRET COMMMANDS

The following commands manipulate "secrets" (e.g. passwords, passphrases and
encryption keys).  Libvirt can store secrets independently from their use, and
other objects (e.g. volumes or domains) can refer to the secrets for encryption
or possibly other uses.  Secrets are identified using an UUID.  See
L<http://libvirt.org/formatsecret.html> for documentation of the XML format
used to represent properties of secrets.

=over 4

=item B<secret-define> I<file>

Create a secret with the properties specified in I<file>, with no associated
secret value.  If I<file> does not specify a UUID, choose one automatically.
If I<file> specifies an UUID of an existing secret, replace its properties by
properties defined in I<file>, without affecting the secret value.

=item B<secret-dumpxml> I<secret>

Output properties of I<secret> (specified by its UUID) as an XML dump to stdout.

=item B<secret-set-value> I<secret> I<base64>

Set the value associated with I<secret> (specified by its UUID) to the value
Base64-encoded value I<base64>.

=item B<secret-get-value> I<secret>

Output the value associated with I<secret> (specified by its UUID) to stdout,
encoded using Base64.

=item B<secret-undefine> I<secret>

Delete a I<secret> (specified by its UUID), including the associated value, if
any.

=item B<secret-list>

Output a list of UUIDs of known secrets to stdout.

=back

=head1 SNAPSHOT COMMMANDS

The following commands manipulate domain snapshots.  Snapshots take the
disk, memory, and device state of a domain at a point-of-time, and save it
for future use.  They have many uses, from saving a "clean" copy of an OS
image to saving a domain's state before a potentially destructive operation.
Snapshots are identified with a unique name.  See
L<http://libvirt.org/formatsnapshot.html> for documentation of the XML format
used to represent properties of snapshots.

=over 4

=item B<snapshot-create> I<domain> I<xmlfile>

Create a snapshot for domain I<domain> with the properties specified in
I<xmlfile>.  The only properties settable for a domain snapshot are the
<name> and <description>; the rest of the fields are ignored, and
automatically filled in by libvirt.  If I<xmlfile> is completely omitted,
then libvirt will choose a value for all fields.

=item B<snapshot-current> I<domain>

Output the snapshot XML for the domain's current snapshot (if any).

=item B<snapshot-list> I<domain>

List all of the available snapshots for the given domain.

=item B<snapshot-dumpxml> I<domain> I<snapshot>

Output the snapshot XML for the domain's snapshot named I<snapshot>.

=item B<snapshot-revert> I<domain> I<snapshot>

Revert the given domain to the snapshot specified by I<snapshot>.  Be aware
that this is a destructive action; any changes in the domain since the
snapshot was taken will be lost.  Also note that the state of the domain after
snapshot-revert is complete will be the state of the domain at the time
the original snapshot was taken.

=item B<snapshot-delete> I<domain> I<snapshot> I<--children>

Delete the snapshot for the domain named I<snapshot>.  If this snapshot
has child snapshots, changes from this snapshot will be merged into the
children.  If I<--children> is passed, then delete this snapshot and any
children of this snapshot.

=back

=head1 NWFILTER COMMMANDS

The following commands manipulate network filters. Network filters allow
filtering of the network traffic coming from and going to virtual machines.
Individual network traffic filters are written in XML and may contain
references to other network filters, describe traffic filtering rules,
or contain both. Network filters are referenced by virtual machines
from within their interface description. A network filter may be referenced
by multiple virtual machines' interfaces.

=over 4

=item B<nwfilter-define> I<xmlfile>

Make a new network filter known to libvirt. If a network filter with
the same name already exists, it will be replaced with the new XML.
Any running virtual machine referencing this network filter will have
its network traffic rules adapted. If for any reason the network traffic
filtering rules cannot be instantiated by any of the running virtual
machines, then the new XML will be rejected.

=item B<nwfilter-undefine> I<nwfilter-name>

Delete a network filter. The deletion will fail if any running virtual
machine is currently using this network filter.

=item B<nwfilter-list>

List all of the available network filters.

=item B<nwfilter-dumpxml> I<nwfilter-name>

Output the network filter XML.

=item B<nwfilter-edit> I<nwfilter-name>

Edit the XML of a network filter.

This is equivalent to:

 virsh nwfilter-dumpxml myfilter > myfilter.xml
 edit myfilter.xml
 virsh nwfilter-define myfilter.xml

except that it does some error checking.
The new network filter may be rejected due to the same reason as
mentioned in I<nwfilter-define>.

The editor used can be supplied by the C<$VISUAL> or C<$EDITOR> environment
variables, and defaults to C<vi>.

=back

=head1 ENVIRONMENT

The following environment variables can be set to alter the behaviour
of C<virsh>

=over 4

=item VIRSH_DEFAULT_CONNECT_URI

The hypervisor to connect to by default. Set this to a URI, in the same
format as accepted by the B<connect> option.

=item VISUAL

The editor to use by the B<edit> and related options.

=item EDITOR

The editor to use by the B<edit> and related options, if C<VISUAL>
is not set.

=item LIBVIRT_DEBUG=LEVEL

Turn on verbose debugging of all libvirt API calls. Valid levels are

=over 4

=item * LIBVIRT_DEBUG=1

Messages at level DEBUG or above

=item * LIBVIRT_DEBUG=2

Messages at level INFO or above

=item * LIBVIRT_DEBUG=3

Messages at level WARNING or above

=item * LIBVIRT_DEBUG=4

Messages at level ERROR or above

=back

For further information about debugging options consult C<http://libvirt.org/logging.html>

=back

=head1 BUGS

Report any bugs discovered to the libvirt community via the mailing
list C<http://libvirt.org/contact.html> or bug tracker C<http://libvirt.org/bugs.html>.
Alternatively report bugs to your software distributor / vendor.

=head1 AUTHORS

  Andrew Puch <apuch @ redhat.com>
  Daniel Veillard <veillard @ redhat.com>

  Based on the xm man page by:
  Sean Dague <sean at dague dot net>
  Daniel Stekloff <dsteklof at us dot ibm dot com>

=head1 COPYRIGHT

Copyright (C) 2005, 2007-2010 Red Hat, Inc.

=head1 LICENSE

virsh is distributed under the terms of the GNU LGPL v2+.
This is free software; see the source for copying conditions. There
is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE

=head1 SEE ALSO

L<virt-install(1)>, L<virt-xml-validate(1)>, L<virt-top(1)>, L<virt-mem(1)>, L<virt-df(1)>, L<http://www.libvirt.org/>

=cut