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ccff335f83
network: static route support for <network>
This patch adds the <route> subelement of <network> to define a static
route. the address and prefix (or netmask) attribute identify the
destination network, and the gateway attribute specifies the next hop
address (which must be directly reachable from the containing
<network>) which is to receive the packets destined for
"address/(prefix|netmask)".
These attributes are translated into an "ip route add" command that is
executed when the network is started. The command used is of the
following form:
ip route add <address>/<prefix> via <gateway> \
dev <virbr-bridge> proto static metric <metric>
Tests are done to validate that the input data are correct. For
example, for a static route ip definition, the address must be a
network address and not a host address. Additional checks are added
to ensure that the specified gateway is directly reachable via this
network (i.e. that the gateway IP address is in the same subnet as one
of the IP's defined for the network).
prefix='0' is supported for both family='ipv4' address='0.0.0.0'
netmask='0.0.0.0' or prefix='0', and for family='ipv6' address='::',
prefix=0', although care should be taken to not override a desired
system default route.
Anytime an attempt is made to define a static route which *exactly*
duplicates an existing static route (for example, address=::,
prefix=0, metric=1), the following error message will be sent to
syslog:
RTNETLINK answers: File exists
This can be overridden by decreasing the metric value for the route
that should be preferred, or increasing the metric for the route that
shouldn't be preferred (and is thus in place only in anticipation that
the preferred route may be removed in the future). Caution should be
used when manipulating route metrics, especially for a default route.
Note: The use of the command-line interface should be replaced by
direct use of libnl so that error conditions can be handled better. But,
that is being left as an exercise for another day.
Signed-off-by: Gene Czarcinski <gene@czarc.net>
Signed-off-by: Laine Stump <laine@laine.org>
1035 lines
48 KiB
XML
1035 lines
48 KiB
XML
<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml">
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<body>
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<h1>Network XML format</h1>
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<ul id="toc">
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</ul>
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<p>
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This page provides an introduction to the network XML format. For background
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information on the concepts referred to here, consult the <a href="archnetwork.html">network driver architecture</a>
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page.
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</p>
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<h2><a name="elements">Element and attribute overview</a></h2>
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<p>
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The root element required for all virtual networks is
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named <code>network</code> and has no configurable attributes
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(although <span class="since">since 0.10.0</span> there is one
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optional read-only attribute - when examining the live
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configuration of a network, the
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attribute <code>connections</code>, if present, specifies the
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number of guest interfaces currently connected via this
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network). The network XML format is
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available <span class="since">since 0.3.0</span>
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</p>
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<h3><a name="elementsMetadata">General metadata</a></h3>
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<p>
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The first elements provide basic metadata about the virtual
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network.
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</p>
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<pre>
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<network ipv6='yes'>
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<name>default</name>
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<uuid>3e3fce45-4f53-4fa7-bb32-11f34168b82b</uuid>
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...</pre>
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<dl>
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<dt><code>name</code></dt>
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<dd>The content of the <code>name</code> element provides
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a short name for the virtual network. This name should
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consist only of alpha-numeric characters and is required
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to be unique within the scope of a single host. It is
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used to form the filename for storing the persistent
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configuration file. <span class="since">Since 0.3.0</span></dd>
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<dt><code>uuid</code></dt>
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<dd>The content of the <code>uuid</code> element provides
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a globally unique identifier for the virtual network.
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The format must be RFC 4122 compliant, eg <code>3e3fce45-4f53-4fa7-bb32-11f34168b82b</code>.
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If omitted when defining/creating a new network, a random
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UUID is generated. <span class="since">Since 0.3.0</span></dd>
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<dt><code>ipv6='yes'</code></dt>
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<dd>The new, optional parameter <code>ipv6='yes'</code> enables
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a network definition with no IPv6 gateway addresses specified
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to have guest-to-guest communications. For further information,
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see the example below for the example with no gateway addresses.
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<span class="since">Since 1.0.1</span></dd>
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</dl>
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<h3><a name="elementsConnect">Connectivity</a></h3>
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<p>
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The next set of elements control how a virtual network is
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provided connectivity to the physical LAN (if at all).
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</p>
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<pre>
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...
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<bridge name="virbr0" stp="on" delay="5"/>
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<domain name="example.com"/>
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<forward mode="nat" dev="eth0"/>
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...</pre>
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<dl>
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<dt><code>bridge</code></dt>
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<dd>The <code>name</code> attribute on the <code>bridge</code> element
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defines the name of a bridge device which will be used to construct
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the virtual network. The virtual machines will be connected to this
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bridge device allowing them to talk to each other. The bridge device
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may also be connected to the LAN. It is recommended that bridge
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device names started with the prefix <code>vir</code>, but the name
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<code>virbr0</code> is reserved for the "default" virtual
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network. This element should always be provided when defining
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a new network with a <code><forward></code> mode of
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"nat" or "route" (or an isolated network with
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no <code><forward></code> element).
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Attribute <code>stp</code> specifies if Spanning Tree Protocol
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is 'on' or 'off' (default is
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'on'). Attribute <code>delay</code> sets the bridge's forward
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delay value in seconds (default is 0).
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<span class="since">Since 0.3.0</span>
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</dd>
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<dt><code>domain</code></dt>
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<dd>
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The <code>name</code> attribute on the <code>domain</code>
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element defines the DNS domain of the DHCP server. This
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element is optional, and is only used for those networks with
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a <code><forward></code> mode of "nat" or "route" (or an
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isolated network with no <code><forward></code>
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element). <span class="since">Since 0.4.5</span>
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</dd>
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<dt><code>forward</code></dt>
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<dd>Inclusion of the <code>forward</code> element indicates that
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the virtual network is to be connected to the physical
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LAN.<span class="since">Since 0.3.0.</span>
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The <code>mode</code> attribute determines the method of
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forwarding. If there is no <code>forward</code> element, the
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network will be isolated from any other network (unless a
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guest connected to that network is acting as a router, of
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course). The following are valid settings
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for <code>mode</code> (if there is a <code>forward</code>
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element but mode is not specified, <code>mode='nat'</code> is
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assumed):
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<dl>
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<dt><code>nat</code></dt>
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<dd>
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All traffic between guests connected to this network and
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the physical network will be forwarded to the physical
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network via the host's IP routing stack, after the guest's
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IP address is translated to appear as the host machine's
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public IP address (a.k.a. Network Address Translation, or
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"NAT"). This allows multiple guests, all having access to
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the physical network, on a host that is only allowed a
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single public IP address. If a network has any IPv6
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addresses defined, the IPv6 traffic will be forwarded
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using plain routing, since IPv6 has no concept of NAT.
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Firewall rules will allow outbound connections to any
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other network device whether ethernet, wireless, dialup,
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or VPN. If the <code>dev</code> attribute is set, the
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firewall rules will restrict forwarding to the named
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device only. Inbound connections from other networks are
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all prohibited; all connections between guests on the same
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network, and to/from the host to the guests, are
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unrestricted and not NATed.<span class="since">Since
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0.4.2</span>
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<p><span class="since">Since 1.0.3</span> it is possible to
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specify a public IPv4 address and port range to be used for
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the NAT by using the <code><nat></code> subelement.
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The address range is set with the <code><address></code>
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subelements and <code>start</code> and <code>stop</code>
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attributes:
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</p>
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<pre>
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...
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<forward mode='nat'>
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<nat>
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<address start='1.2.3.4' end='1.2.3.10'/>
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</nat>
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</forward>
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...</pre>
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<p>
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An singe IPv4 address can be set by setting
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<code>start</code> and <code>end</code> attributes to
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the same value.
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</p>
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<p>
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The port range to be used for the <code><nat></code> can
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be set via the subelement <code><port></code>:
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</p>
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<pre>
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...
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<forward mode='nat'>
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<nat>
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<port start='500' end='1000'/>
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</nat>
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</forward>
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...</pre>
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</dd>
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<dt><code>route</code></dt>
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<dd>
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Guest network traffic will be forwarded to the physical
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network via the host's IP routing stack, but without
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having NAT applied. Again, if the <code>dev</code>
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attribute is set, firewall rules will restrict forwarding
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to the named device only. This presumes that the local LAN
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router has suitable routing table entries to return
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traffic to this host. All incoming and outgoing sessions
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to guest on these networks are unrestricted. (To restrict
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incoming traffic to a guest on a routed network, you can
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configure <a href="formatnwfilter.html">nwfilter rules</a>
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on the guest's interfaces.)
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<span class="since">Since 0.4.2</span>
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</dd>
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<dt><code>bridge</code></dt>
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<dd>
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This network describes either 1) an existing host bridge
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that was configured outside of libvirt (if
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a <code><bridge name='xyz'/></code> element has been
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specified, <span class="since">Since 0.9.4</span>), 2) an
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existing Open vSwitch bridge that was configured outside of
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libvirt (if both a <code><bridge name='xyz'/></code>
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element <b>and</b> a <code><virtualport
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type='openvswitch'/></code> have been
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specified <span class="since">Since 0.10.0</span>) 3) an
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interface or group of interfaces to be used for a "direct"
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connection via macvtap using macvtap's "bridge" mode (if
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the forward element has one or
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more <code><interface></code>
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subelements, <span class="since">Since 0.9.4</span>)
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(see <a href="formatdomain.html#elementsNICSDirect">Direct
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attachment to physical interface</a> for descriptions of
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the various macvtap modes). libvirt doesn't attempt to
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manage the bridge interface at all, thus
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the <code><bridge></code> element's <code>stp</code>
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and <code>delay</code> attributes are not allowed; no
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iptables rules, IP addresses, or DHCP/DNS services are
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added; at the IP level, the guest interface appears to be
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directly connected to the physical
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interface.<span class="since">Since 0.9.4</span>
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</dd>
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<dt><code>private</code></dt>
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<dd>
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This network uses a macvtap "direct" connection in
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"private" mode to connect each guest to the network. The
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physical interface to be used will be picked from among
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those listed in <code><interface></code> subelements
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of the <code><forward></code> element; when using
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802.1Qbh mode (as indicated by
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the <code><virtualport></code> type attribute - note
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that this requires an 802.1Qbh-capable hardware switch),
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each physical interface can only be in use by a single
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guest interface at a time; in modes other than 802.1Qbh,
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multiple guest interfaces can share each physical
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interface (libvirt will attempt to balance usage between
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all available interfaces).<span class="since">Since
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0.9.4</span>
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</dd>
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<dt><code>vepa</code></dt>
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<dd>
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This network uses a macvtap "direct" connection in "vepa"
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mode to connect each guest to the network (this requires
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that the physical interfaces used be connected to a
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vepa-capable hardware switch. The physical interface to be
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used will be picked from among those listed
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in <code><interface></code> subelements of
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the <code><forward></code> element; multiple guest
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interfaces can share each physical interface (libvirt will
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attempt to balance usage between all available
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interfaces).<span class="since">Since 0.9.4</span>
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</dd>
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<dt><code>passthrough</code></dt>
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<dd>
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This network uses a macvtap "direct" connection in
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"passthrough" mode to connect each guest to the network
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(note that this is <i>not</i> the same thing as "PCI
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passthrough"). The physical interface to be used will be
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picked from among those listed
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in <code><interface></code> subelements of
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the <code><forward></code> element. Each physical
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interface can only be in use by a single guest interface
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at a time, so libvirt will keep track of which interfaces
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are currently in use, and only assign unused interfaces
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(if there are no available physical interfaces when a
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domain interface is being attached, an error will be
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logged, and the operation causing the attach will fail
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(usually either a domain start, or a hotplug interface
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attach to a domain).<span class="since">Since 0.9.4</span>
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</dd>
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<dt><code>hostdev</code></dt>
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<dd>
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This network facilitates PCI Passthrough of a network
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device. A network device is chosen from the interface
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pool and directly assigned to the guest using generic
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device passthrough, after first optionally setting the
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device's MAC address and vlan tag to the configured value,
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and optionally associating the device with an 802.1Qbh
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capable switch using a <code><virtualport></code>
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element. Note that - due to limitations in standard
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single-port PCI ethernet card driver design - only SR-IOV
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(Single Root I/O Virtualization) virtual function (VF)
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devices can be assigned in this manner; to assign a
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standard single-port PCI or PCIe ethernet card to a guest,
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use the traditional <code>< hostdev></code> device
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definition. <span class="since"> Since 0.10.0</span>
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<p>
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To use VFIO device assignment rather than
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traditional/legacy KVM device assignment (VFIO is a new
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method of device assignment that is compatible with UEFI
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Secure Boot), a <forward type='hostdev'> interface
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can have an optional <code>driver</code> sub-element
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with a <code>name</code> attribute set to "vfio". To use
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legacy KVM device assignment you can
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set <code>name</code> to "kvm" (or simply omit the
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<driver> element, since "kvm" is currently the
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default).
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<span class="since">Since 1.0.5 (QEMU and KVM only, requires kernel 3.6 or newer)</span>
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</p>
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<p>Note that this "intelligent passthrough" of network
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devices is very similar to the functionality of a
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standard <code>< hostdev></code> device, the
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difference being that this method allows specifying a MAC
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address, vlan tag, and <code><virtualport ></code>
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for the passed-through device. If these capabilities are
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not required, if you have a standard single-port PCI,
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PCIe, or USB network card that doesn't support SR-IOV (and
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hence would anyway lose the configured MAC address during
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reset after being assigned to the guest domain), or if you
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are using a version of libvirt older than 0.10.0, you
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should use a standard
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<code><hostdev></code> device definition in the
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domain's configuration to assign the device to the guest
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instead of defining an <code><interface
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type='network'></code> pointing to a network
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with <code><forward mode='hostdev'/></code>.
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</p>
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</dd>
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</dl>
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As mentioned above, a <code><forward></code> element can
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have multiple <code><interface></code> subelements, each
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one giving the name of a physical interface that can be used
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for this network <span class="since">Since 0.9.4</span>:
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<pre>
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...
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<forward mode='passthrough'>
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<interface dev='eth10'/>
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<interface dev='eth11'/>
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<interface dev='eth12'/>
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<interface dev='eth13'/>
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<interface dev='eth14'/>
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</forward>
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...
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</pre>
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<p>
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<span class="since">since 0.10.0</span>,
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<code><interface></code> also has an optional read-only
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attribute - when examining the live configuration of a
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network, the attribute <code>connections</code>, if present,
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specifies the number of guest interfaces currently connected
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via this physical interface.
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</p>
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<p>
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Additionally, <span class="since">since 0.9.10</span>, libvirt
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allows a shorthand for specifying all virtual interfaces
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associated with a single physical function, by using
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the <code><pf></code> subelement to call out the
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corresponding physical interface associated with multiple
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virtual interfaces:
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</p>
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<pre>
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...
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<forward mode='passthrough'>
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<pf dev='eth0'/>
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</forward>
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...
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</pre>
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<p>When a guest interface is being constructed, libvirt will pick
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an interface from this list to use for the connection. In
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modes where physical interfaces can be shared by multiple
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guest interfaces, libvirt will choose the interface that
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currently has the least number of connections. For those modes
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that do not allow sharing of the physical device (in
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particular, 'passthrough' mode, and 'private' mode when using
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802.1Qbh), libvirt will choose an unused physical interface
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or, if it can't find an unused interface, fail the operation.</p>
|
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|
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<p>
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<span class="since">since 0.10.0</span> When using forward
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mode 'hostdev', the interface pool is specified with a list
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of <code><address></code> elements, each of which has
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<code>< type></code> (must always be <code>'pci'</code>,
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<code><domain></code>, <code><bus></code>,
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<code><slot></code>, and <code><function></code>
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attributes.
|
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</p>
|
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<pre>
|
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...
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<forward mode='hostdev' managed='yes'>
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<driver name='vfio'/>
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<address type='pci' domain='0' bus='4' slot='0' function='1'/>
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<address type='pci' domain='0' bus='4' slot='0' function='2'/>
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<address type='pci' domain='0' bus='4' slot='0' function='3'/>
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</forward>
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...
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</pre>
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|
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Alternatively the interface pool can also be defined using a
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single physical function <code><pf></code> subelement to
|
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call out the corresponding physical interface associated with
|
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multiple virtual interfaces (similar to passthrough mode):
|
|
|
|
<pre>
|
|
...
|
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<forward mode='hostdev' managed='yes'>
|
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<pf dev='eth0'/>
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</forward>
|
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...
|
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</pre>
|
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|
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</dd>
|
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</dl>
|
|
<h5><a name="elementQoS">Quality of service</a></h5>
|
|
|
|
<pre>
|
|
...
|
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<forward mode='nat' dev='eth0'/>
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<b><bandwidth>
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<inbound average='1000' peak='5000' burst='5120'/>
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<outbound average='128' peak='256' burst='256'/>
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</bandwidth></b>
|
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...</pre>
|
|
|
|
<p>
|
|
This part of network XML provides setting quality of service. Incoming
|
|
and outgoing traffic can be shaped independently. The
|
|
<code>bandwidth</code> element can have at most one <code>inbound</code>
|
|
and at most one <code>outbound</code> child elements. Leaving any of these
|
|
children element out result in no QoS applied on that traffic direction.
|
|
So, when you want to shape only network's incoming traffic, use
|
|
<code>inbound</code> only, and vice versa. Each of these elements have one
|
|
mandatory attribute <code>average</code>. It specifies average bit rate on
|
|
interface being shaped. Then there are two optional attributes:
|
|
<code>peak</code>, which specifies maximum rate at which bridge can send
|
|
data, and <code>burst</code>, amount of bytes that can be burst at
|
|
<code>peak</code> speed. Accepted values for attributes are integer
|
|
numbers, The units for <code>average</code> and <code>peak</code> attributes
|
|
are kilobytes per second, and for the <code>burst</code> just kilobytes.
|
|
The rate is shared equally within domains connected to the network.
|
|
Moreover, <code>bandwidth</code> element can be included in
|
|
<code>portgroup</code> element.
|
|
<span class="since">Since 0.9.4</span>
|
|
</p>
|
|
|
|
<h5><a name="elementVlanTag">Setting VLAN tag (on supported network types only)</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<devices>
|
|
<interface type='bridge'>
|
|
<b><vlan trunk='yes'></b>
|
|
<b><tag id='42'/></b>
|
|
<b><tag id='47'/></b>
|
|
<b></vlan></b>
|
|
<source bridge='ovsbr0'/>
|
|
<virtualport type='openvswitch'>
|
|
<parameters interfaceid='09b11c53-8b5c-4eeb-8f00-d84eaa0aaa4f'/>
|
|
</virtualport>
|
|
</interface>
|
|
<devices>
|
|
...</pre>
|
|
|
|
<p>
|
|
If (and only if) the network type supports vlan tagging
|
|
transparent to the guest, an optional <code><vlan></code>
|
|
element can specify one or more vlan tags to apply to the
|
|
traffic of all guests using this
|
|
network <span class="since">Since 0.10.0</span>. (openvswitch
|
|
and type='hostdev' SR-IOV networks do support transparent vlan
|
|
tagging of guest traffic; everything else, including standard
|
|
linux bridges and libvirt's own virtual networks, <b>do not</b>
|
|
support it. 802.1Qbh (vn-link) and 802.1Qbg (VEPA) switches
|
|
provide their own way (outside of libvirt) to tag guest traffic
|
|
onto specific vlans.) As expected, the <code>tag</code>
|
|
attribute specifies which vlan tag to use. If a network has more
|
|
than one <code><vlan></code> element defined, it is
|
|
assumed that the user wants to do VLAN trunking using all the
|
|
specified tags. In the case that vlan trunking with a single tag
|
|
is desired, the optional attribute <code>trunk='yes'</code> can
|
|
be added to the vlan element.
|
|
</p>
|
|
<p>
|
|
<code><vlan></code> elements can also be specified in
|
|
a <code><portgroup></code> element, as well as directly in
|
|
a domain's <code><interface></code> element. In the case
|
|
that a vlan tag is specified in multiple locations, the setting
|
|
in <code><interface></code> takes precedence, followed by
|
|
the setting in the <code><portgroup></code> selected by
|
|
the interface config. The <code><vlan></code>
|
|
in <code><network></code> will be selected only if none is
|
|
given in <code><portgroup></code>
|
|
or <code><interface></code>.
|
|
</p>
|
|
|
|
<h5><a name="elementsPortgroup">Portgroups</a></h5>
|
|
|
|
<pre>
|
|
...
|
|
<forward mode='private'/>
|
|
<interface dev="eth20"/>
|
|
<interface dev="eth21"/>
|
|
<interface dev="eth22"/>
|
|
<interface dev="eth23"/>
|
|
<interface dev="eth24"/>
|
|
</forward>
|
|
<b><portgroup name='engineering' default='yes'>
|
|
<virtualport type='802.1Qbh'>
|
|
<parameters profileid='test'/>
|
|
</virtualport>
|
|
<bandwidth>
|
|
<inbound average='1000' peak='5000' burst='5120'/>
|
|
<outbound average='1000' peak='5000' burst='5120'/>
|
|
</bandwidth>
|
|
</portgroup></b>
|
|
<b><portgroup name='sales'>
|
|
<virtualport type='802.1Qbh'>
|
|
<parameters profileid='salestest'/>
|
|
</virtualport>
|
|
<bandwidth>
|
|
<inbound average='500' peak='2000' burst='2560'/>
|
|
<outbound average='128' peak='256' burst='256'/>
|
|
</bandwidth>
|
|
</portgroup></b>
|
|
...</pre>
|
|
|
|
<p>
|
|
<span class="since">Since 0.9.4</span>
|
|
A portgroup provides a method of easily putting guest
|
|
connections to the network into different classes, with each
|
|
class potentially having a different level/type of service.
|
|
<span class="since">Since 0.9.4</span> Each
|
|
network can have multiple portgroup elements (and one of those
|
|
can optionally be designated as the 'default' portgroup for the
|
|
network), and each portgroup has a name, as well as various
|
|
subelements associated with it. The currently supported
|
|
subelements are <code><bandwidth></code>
|
|
(documented <a href="formatdomain.html#elementQoS">here</a>)
|
|
and <code><virtualport></code>
|
|
(documented <a href="formatdomain.html#elementsNICSDirect">here</a>).
|
|
If a domain interface definition specifies a portgroup (by
|
|
adding a <code>portgroup</code> attribute to
|
|
the <code><source></code> subelement), that portgroup's
|
|
info will be merged into the interface's configuration. If no
|
|
portgroup is given in the interface definition, and one of the
|
|
network's portgroups has <code>default='yes'</code>, that
|
|
default portgroup will be used. If no portgroup is given in the
|
|
interface definition, and there is no default portgroup, then
|
|
none will be used. Any <code><bandwidth></code>
|
|
|
|
specified directly in the domain XML will take precedence over
|
|
any setting in the chosen portgroup. if
|
|
a <code><virtualport></code> is specified in the portgroup
|
|
(and/or directly in the network definition), the multiple
|
|
virtualports will be merged, and any parameter that is specified
|
|
in more than one virtualport, and is not identical, will be
|
|
considered an error, and will prevent the interface from
|
|
starting.
|
|
</p>
|
|
|
|
<h5><a name="elementsStaticroute">Static Routes</a></h5>
|
|
<p>
|
|
Static route definitions are used to provide routing information
|
|
to the virtualization host for networks which are not directly
|
|
reachable from the virtualization host, but *are* reachable from
|
|
a guest domain that is itself reachable from the
|
|
host <span class="since">since 1.0.6</span>.
|
|
</p>
|
|
|
|
<p>
|
|
As shown in <a href="formatnetwork.html#examplesNoGateway">this
|
|
example</a>, it is possible to define a virtual network
|
|
interface with no IPv4 or IPv6 addresses. Such networks are
|
|
useful to provide host connectivity to networks which are only
|
|
reachable via a guest. A guest with connectivity both to the
|
|
guest-only network and to another network that is directly
|
|
reachable from the host can act as a gateway between the
|
|
networks. A static route added to the "host-visible" network
|
|
definition provides the routing information so that IP packets
|
|
can be sent from the virtualization host to guests on the hidden
|
|
network.
|
|
</p>
|
|
|
|
<p>
|
|
Here is a fragment of a definition which shows the static
|
|
route specification as well as the IPv4 and IPv6 definitions
|
|
for network addresses which are referred to in the
|
|
<code>gateway</code> gateway address specifications. Note
|
|
that the third static route specification includes the
|
|
<code>metric</code> attribute specification with a value of 2.
|
|
This particular route would *not* be preferred if there was
|
|
another existing rout on the system with the same address and
|
|
prefix but with a lower value for the metric. If there is a
|
|
route in the host system configuration that should be overriden
|
|
by a route in a virtual network whenever the virtual network is
|
|
running, the configuration for the system-defined route should
|
|
be modified to have a higher metric, and the route on the
|
|
virtual network given a lower metric (for example, the default
|
|
metric of "1").
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<ip address="192.168.122.1" netmask="255.255.255.0">
|
|
<dhcp>
|
|
<range start="192.168.122.128" end="192.168.122.254" />
|
|
</dhcp>
|
|
</ip>
|
|
<route address="192.168.222.0" prefix="24" gateway="192.168.122.2" />
|
|
<ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" />
|
|
<route family="ipv6" address="2001:db8:ca2:3::" prefix="64" gateway="2001:db8:ca2:2::2"/>
|
|
<route family="ipv6" address="2001:db9:4:1::" prefix="64" gateway="2001:db8:ca2:2::3" metric='2'>
|
|
</route>
|
|
...
|
|
</pre>
|
|
|
|
<h3><a name="elementsAddress">Addressing</a></h3>
|
|
|
|
<p>
|
|
The final set of elements define the addresses (IPv4 and/or
|
|
IPv6, as well as MAC) to be assigned to the bridge device
|
|
associated with the virtual network, and optionally enable DHCP
|
|
services. These elements are only valid for isolated networks
|
|
(no <code>forward</code> element specified), and for those with
|
|
a forward mode of 'route' or 'nat'.
|
|
</p>
|
|
|
|
<pre>
|
|
...
|
|
<mac address='00:16:3E:5D:C7:9E'/>
|
|
<domain name="example.com"/>
|
|
<dns>
|
|
<txt name="example" value="example value" />
|
|
<srv service='name' protocol='tcp' domain='test-domain-name' target='.' port='1024' priority='10' weight='10'/>
|
|
<host ip='192.168.122.2'>
|
|
<hostname>myhost</hostname>
|
|
<hostname>myhostalias</hostname>
|
|
</host>
|
|
</dns>
|
|
<ip address="192.168.122.1" netmask="255.255.255.0">
|
|
<dhcp>
|
|
<range start="192.168.122.100" end="192.168.122.254" />
|
|
<host mac="00:16:3e:77:e2:ed" name="foo.example.com" ip="192.168.122.10" />
|
|
<host mac="00:16:3e:3e:a9:1a" name="bar.example.com" ip="192.168.122.11" />
|
|
</dhcp>
|
|
</ip>
|
|
<ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" />
|
|
<route family="ipv6" address="2001:db9:ca1:1::" prefix="64" gateway="2001:db8:ca2:2::2" />
|
|
</network></pre>
|
|
|
|
<dl>
|
|
<dt><code>mac</code></dt>
|
|
<dd>The <code>address</code> attribute defines a MAC
|
|
(hardware) address formatted as 6 groups of 2-digit
|
|
hexadecimal numbers, the groups separated by colons
|
|
(eg, <code>"52:54:00:1C:DA:2F"</code>). This MAC address is
|
|
assigned to the bridge device when it is created. Generally
|
|
it is best to not specify a MAC address when creating a
|
|
network - in this case, if a defined MAC address is needed for
|
|
proper operation, libvirt will automatically generate a random
|
|
MAC address and save it in the config. Allowing libvirt to
|
|
generate the MAC address will assure that it is compatible
|
|
with the idiosyncrasies of the platform where libvirt is
|
|
running. <span class="since">Since 0.8.8</span>
|
|
</dd>
|
|
<dt><code>dns</code></dt><dd>
|
|
The dns element of a network contains configuration information for the
|
|
virtual network's DNS server. <span class="since">Since 0.9.3</span>
|
|
Currently supported elements are:
|
|
<dl>
|
|
<dt><code>txt</code></dt>
|
|
<dd>A <code>dns</code> element can have 0 or more <code>txt</code> elements.
|
|
Each txt element defines a DNS TXT record and has two attributes, both
|
|
required: a name that can be queried via dns, and a value that will be
|
|
returned when that name is queried. names cannot contain embedded spaces
|
|
or commas. value is a single string that can contain multiple values
|
|
separated by commas. <span class="since">Since 0.9.3</span>
|
|
</dd>
|
|
<dt><code>host</code></dt>
|
|
<dd>The <code>host</code> element within <code>dns</code> is the
|
|
definition of DNS hosts to be passed to the DNS service. The IP
|
|
address is identified by the <code>ip</code> attribute and the names
|
|
for that IP address are identified in the <code>hostname</code>
|
|
sub-elements of the <code>host</code> element.
|
|
<span class="since">Since 0.9.3</span>
|
|
</dd>
|
|
</dl>
|
|
<dl>
|
|
<dt><code>srv</code></dt>
|
|
<dd>The <code>dns</code> element can have also 0 or more <code>srv</code>
|
|
record elements. Each <code>srv</code> record element defines a DNS SRV record
|
|
and has 2 mandatory and 5 optional attributes. The mandatory attributes
|
|
are service name and protocol (tcp, udp) and the optional attributes are
|
|
target, port, priority, weight and domain as defined in DNS server SRV
|
|
RFC (RFC 2782).
|
|
<span class="since">Since 0.9.9</span>
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
<dt><code>ip</code></dt>
|
|
<dd>The <code>address</code> attribute defines an IPv4 address in
|
|
dotted-decimal format, or an IPv6 address in standard
|
|
colon-separated hexadecimal format, that will be configured on
|
|
the bridge
|
|
device associated with the virtual network. To the guests this IPv4
|
|
address will be their IPv4 default route. For IPv6, the default route is
|
|
established via Router Advertisement.
|
|
For IPv4 addresses, the <code>netmask</code>
|
|
attribute defines the significant bits of the network address,
|
|
again specified in dotted-decimal format. For IPv6 addresses,
|
|
and as an alternate method for IPv4 addresses, you can specify
|
|
the significant bits of the network address with the <code>prefix</code>
|
|
attribute, which is an integer (for example, <code>netmask='255.255.255.0'</code>
|
|
could also be given as <code>prefix='24'</code>. The <code>family</code>
|
|
attribute is used to specify the type of address - 'ipv4' or 'ipv6'; if no
|
|
<code>family</code> is given, 'ipv4' is assumed. A network can have more than
|
|
one of each family of address defined, but only a single IPv4 address can have a
|
|
<code>dhcp</code> or <code>tftp</code> element. <span class="since">Since 0.3.0 </span>
|
|
IPv6, multiple addresses on a single network, <code>family</code>, and
|
|
<code>prefix</code> are support <span class="since">Since 0.8.7</span>.
|
|
Similar to IPv4, one IPv6 address per network can also have
|
|
a <code>dhcp</code> definition. <span class="since">Since 1.0.1</span>
|
|
|
|
<dl>
|
|
<dt><code>tftp</code></dt>
|
|
<dd>Immediately within
|
|
the <code>ip</code> element there is an optional <code>tftp</code>
|
|
element. The presence of this element and of its attribute
|
|
<code>root</code> enables TFTP services. The attribute specifies
|
|
the path to the root directory served via TFTP. <code>tftp</code> is not
|
|
supported for IPv6 addresses, and can only be specified on a single IPv4 address
|
|
per network.
|
|
<span class="since">Since 0.7.1</span>
|
|
</dd>
|
|
|
|
<dt><code>dhcp</code></dt>
|
|
<dd>Also within the <code>ip</code> element there is an
|
|
optional <code>dhcp</code> element. The presence of this element
|
|
enables DHCP services on the virtual network. It will further
|
|
contain one or more <code>range</code> elements. The
|
|
<code>dhcp</code> element supported for both
|
|
IPv4 <span class="since">Since 0.3.0</span>
|
|
and IPv6 <span class="since">Since 1.0.1</span>, but
|
|
only for one IP address of each type per network.
|
|
<dl>
|
|
<dt><code>range</code></dt>
|
|
<dd>The <code>start</code> and <code>end</code> attributes on the
|
|
<code>range</code> element specify the boundaries of a pool of
|
|
addresses to be provided to DHCP clients. These two addresses
|
|
must lie within the scope of the network defined on the parent
|
|
<code>ip</code> element. There may be zero or more
|
|
<code>range</code> elements specified.
|
|
<span class="since">Since 0.3.0</span>
|
|
<code>range</code> can be specified for one IPv4 address,
|
|
one IPv6 address, or both. <span class="since">Since 1.0.1</span>
|
|
</dd>
|
|
<dt><code>host</code></dt>
|
|
<dd>Within the <code>dhcp</code> element there may be zero or more
|
|
<code>host</code> elements. These specify hosts which will be given
|
|
names and predefined IP addresses by the built-in DHCP server. Any
|
|
IPv4 <code>host</code> element must specify the MAC address of the host to be assigned
|
|
a given name (via the <code>mac</code> attribute), the IP to be
|
|
assigned to that host (via the <code>ip</code> attribute), and the
|
|
name to be given that host by the DHCP server (via the
|
|
<code>name</code> attribute). <span class="since">Since 0.4.5</span>
|
|
An IPv6 <code>host</code> element differs slightly from that for IPv4:
|
|
there is no <code>mac</code> attribute since a MAC address has no
|
|
defined meaning in IPv6. Instead, the <code>name</code> attribute is
|
|
used to identify the host to be assigned the IPv6 address. For DHCPv6,
|
|
the name is the plain name of the client host sent by the
|
|
client to the server. Note that this method of assigning a
|
|
specific IP address can also be used instead of the <code>mac</code>
|
|
attribute for IPv4. <span class="since">Since 1.0.1</span>
|
|
</dd>
|
|
<dt><code>bootp</code></dt>
|
|
<dd>The optional <code>bootp</code>
|
|
element specifies BOOTP options to be provided by the DHCP
|
|
server for IPv4 only.
|
|
Two attributes are supported: <code>file</code> is mandatory and
|
|
gives the file to be used for the boot image; <code>server</code> is
|
|
optional and gives the address of the TFTP server from which the boot
|
|
image will be fetched. <code>server</code> defaults to the same host
|
|
that runs the DHCP server, as is the case when the <code>tftp</code>
|
|
element is used. The BOOTP options currently have to be the same
|
|
for all address ranges and statically assigned addresses.<span
|
|
class="since">Since 0.7.1 (<code>server</code> since 0.7.3).</span>
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
</dl>
|
|
</dd>
|
|
</dl>
|
|
|
|
<h2><a name="examples">Example configuration</a></h2>
|
|
|
|
<h3><a name="examplesNAT">NAT based network</a></h3>
|
|
|
|
<p>
|
|
This example is the so called "default" virtual network. It is
|
|
provided and enabled out-of-the-box for all libvirt installations.
|
|
This is a configuration that allows guest OS to get outbound
|
|
connectivity regardless of whether the host uses ethernet, wireless,
|
|
dialup, or VPN networking without requiring any specific admin
|
|
configuration. In the absence of host networking, it at least allows
|
|
guests to talk directly to each other.
|
|
</p>
|
|
|
|
<pre>
|
|
<network>
|
|
<name>default</name>
|
|
<bridge name="virbr0" />
|
|
<forward mode="nat"/>
|
|
<ip address="192.168.122.1" netmask="255.255.255.0">
|
|
<dhcp>
|
|
<range start="192.168.122.2" end="192.168.122.254" />
|
|
</dhcp>
|
|
</ip>
|
|
<ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" />
|
|
</network></pre>
|
|
|
|
|
|
<p>
|
|
Below is a variation of the above example which adds an IPv6
|
|
dhcp range definition.
|
|
</p>
|
|
|
|
<pre>
|
|
<network>
|
|
<name>default6</name>
|
|
<bridge name="virbr0" />
|
|
<forward mode="nat"/>
|
|
<ip address="192.168.122.1" netmask="255.255.255.0">
|
|
<dhcp>
|
|
<range start="192.168.122.2" end="192.168.122.254" />
|
|
</dhcp>
|
|
</ip>
|
|
<ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" >
|
|
<dhcp>
|
|
<range start="2001:db8:ca2:2:1::10" end="2001:db8:ca2:2:1::ff" />
|
|
</dhcp>
|
|
</ip>
|
|
</network></pre>
|
|
|
|
<h3><a name="examplesRoute">Routed network config</a></h3>
|
|
|
|
<p>
|
|
This is a variant on the default network which routes traffic
|
|
from the virtual network to the LAN without applying any NAT.
|
|
It requires that the IP address range be pre-configured in the
|
|
routing tables of the router on the host network. This example
|
|
further specifies that guest traffic may only go out via the
|
|
<code>eth1</code> host network device.
|
|
</p>
|
|
|
|
<pre>
|
|
<network>
|
|
<name>local</name>
|
|
<bridge name="virbr1" />
|
|
<forward mode="route" dev="eth1"/>
|
|
<ip address="192.168.122.1" netmask="255.255.255.0">
|
|
<dhcp>
|
|
<range start="192.168.122.2" end="192.168.122.254" />
|
|
</dhcp>
|
|
</ip>
|
|
<ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" />
|
|
</network></pre>
|
|
|
|
<p>
|
|
Below is another IPv6 variation. Instead of a dhcp range being
|
|
specified, this example has a couple of IPv6 host definitions.
|
|
Note that most of the dhcp host definitions use an "id" (client
|
|
id or DUID) since this has proven to be a more reliable way
|
|
of specifying the interface and its association with an IPv6
|
|
address. The first is a DUID-LLT, the second a DUID-LL, and
|
|
the third a DUID-UUID. <span class="since">Since 1.0.3</span>
|
|
</p>
|
|
|
|
<pre>
|
|
<network>
|
|
<name>local6</name>
|
|
<bridge name="virbr1" />
|
|
<forward mode="route" dev="eth1"/>
|
|
<ip address="192.168.122.1" netmask="255.255.255.0">
|
|
<dhcp>
|
|
<range start="192.168.122.2" end="192.168.122.254" />
|
|
</dhcp>
|
|
</ip>
|
|
<ip family="ipv6" address="2001:db8:ca2:2::1" prefix="64" >
|
|
<dhcp>
|
|
<host name="paul" ip="2001:db8:ca2:2:3::1" />
|
|
<host id="0:1:0:1:18:aa:62:fe:0:16:3e:44:55:66" ip="2001:db8:ca2:2:3::2" />
|
|
<host id="0:3:0:1:0:16:3e:11:22:33" name="ralph" ip="2001:db8:ca2:2:3::3" />
|
|
<host id="0:4:7e:7d:f0:7d:a8:bc:c5:d2:13:32:11:ed:16:ea:84:63" name="badbob" ip="2001:db8:ca2:2:3::4" />
|
|
</dhcp>
|
|
</ip>
|
|
</network></pre>
|
|
|
|
<p>
|
|
Below is yet another IPv6 variation. This variation has only
|
|
IPv6 defined with DHCPv6 on the primary IPv6 network. A static
|
|
link if defined for a second IPv6 network which will not be
|
|
directly visible on the bridge interface but there will be a
|
|
static route defined for this network via the specified
|
|
gateway. Note that the gateway address must be directly
|
|
reachable via (on the same subnet as) one of the <ip>
|
|
addresses defined for this <network>.
|
|
<span class="since">Since 1.0.6</span>
|
|
</p>
|
|
|
|
<pre>
|
|
<network>
|
|
<name>net7</name>
|
|
<bridge name="virbr7" />
|
|
<forward mode="route"/>
|
|
<ip family="ipv6" address="2001:db8:ca2:7::1" prefix="64" >
|
|
<dhcp>
|
|
<range start="2001:db8:ca2:7::100" end="2001:db8:ca2::1ff" />
|
|
<host id="0:4:7e:7d:f0:7d:a8:bc:c5:d2:13:32:11:ed:16:ea:84:63" name="lucas" ip="2001:db8:ca2:2:3::4" />
|
|
</dhcp>
|
|
</ip>
|
|
<route family="ipv6" address="2001:db8:ca2:8::" prefix="64" gateway="2001:db8:ca2:7::4" >
|
|
</route>
|
|
</network></pre>
|
|
|
|
<h3><a name="examplesPrivate">Isolated network config</a></h3>
|
|
|
|
<p>
|
|
This variant provides a completely isolated private network
|
|
for guests. The guests can talk to each other, and the host
|
|
OS, but cannot reach any other machines on the LAN, due to
|
|
the omission of the <code>forward</code> element in the XML
|
|
description.
|
|
</p>
|
|
|
|
<pre>
|
|
<network>
|
|
<name>private</name>
|
|
<bridge name="virbr2" />
|
|
<ip address="192.168.152.1" netmask="255.255.255.0">
|
|
<dhcp>
|
|
<range start="192.168.152.2" end="192.168.152.254" />
|
|
</dhcp>
|
|
</ip>
|
|
<ip family="ipv6" address="2001:db8:ca2:3::1" prefix="64" />
|
|
</network></pre>
|
|
|
|
<h3><a name="examplesPrivate6">Isolated IPv6 network config</a></h3>
|
|
|
|
<p>
|
|
This variation of an isolated network defines only IPv6.
|
|
Note that most of the dhcp host definitions use an "id" (client
|
|
id or DUID) since this has proven to be a more reliable way
|
|
of specifying the interface and its association with an IPv6
|
|
address. The first is a DUID-LLT, the second a DUID-LL, and
|
|
the third a DUID-UUID. <span class="since">Since 1.0.3</span>
|
|
</p>
|
|
|
|
<pre>
|
|
<network>
|
|
<name>sixnet</name>
|
|
<bridge name="virbr6" />
|
|
<ip family="ipv6" address="2001:db8:ca2:6::1" prefix="64" >
|
|
<dhcp>
|
|
<host name="peter" ip="2001:db8:ca2:6:6::1" />
|
|
<host id="0:1:0:1:18:aa:62:fe:0:16:3e:44:55:66" ip="2001:db8:ca2:6:6::2" />
|
|
<host id="0:3:0:1:0:16:3e:11:22:33" name="dariusz" ip="2001:db8:ca2:6:6::3" />
|
|
<host id="0:4:7e:7d:f0:7d:a8:bc:c5:d2:13:32:11:ed:16:ea:84:63" name="anita" ip="2001:db8:ca2:6:6::4" />
|
|
</dhcp>
|
|
</ip>
|
|
</network></pre>
|
|
|
|
<h3><a name="examplesBridge">Using an existing host bridge</a></h3>
|
|
|
|
<p>
|
|
<span class="since">Since 0.9.4</span>
|
|
This shows how to use a pre-existing host bridge "br0". The
|
|
guests will effectively be directly connected to the physical
|
|
network (i.e. their IP addresses will all be on the subnet of
|
|
the physical network, and there will be no restrictions on
|
|
inbound or outbound connections).
|
|
</p>
|
|
|
|
<pre>
|
|
<network>
|
|
<name>host-bridge</name>
|
|
<forward mode="bridge"/>
|
|
<bridge name="br0"/>
|
|
</network></pre>
|
|
|
|
<h3><a name="examplesDirect">Using a macvtap "direct" connection</a></h3>
|
|
|
|
<p>
|
|
<span class="since">Since 0.9.4, QEMU and KVM only, requires
|
|
Linux kernel 2.6.34 or newer</span>
|
|
This shows how to use macvtap to connect to the physical network
|
|
directly through one of a group of physical devices (without
|
|
using a host bridge device). As with the host bridge network,
|
|
the guests will effectively be directly connected to the
|
|
physical network so their IP addresses will all be on the subnet
|
|
of the physical network, and there will be no restrictions on
|
|
inbound or outbound connections. Note that, due to a limitation
|
|
in the implementation of macvtap, these connections do not allow
|
|
communication directly between the host and the guests - if you
|
|
require this you will either need the attached physical switch
|
|
to be operating in a mirroring mode (so that all traffic coming
|
|
to the switch is reflected back to the host's interface), or
|
|
provide alternate means for this communication (e.g. a second
|
|
interface on each guest that is connected to an isolated
|
|
network). The other forward modes that use macvtap (private,
|
|
vepa, and passthrough) would be used in a similar fashion.
|
|
</p>
|
|
|
|
<pre>
|
|
<network>
|
|
<name>direct-macvtap</name>
|
|
<forward mode="bridge">
|
|
<interface dev="eth20"/>
|
|
<interface dev="eth21"/>
|
|
<interface dev="eth22"/>
|
|
<interface dev="eth23"/>
|
|
<interface dev="eth24"/>
|
|
</forward>
|
|
</network></pre>
|
|
|
|
<h3><a name="examplesNoGateway">Network config with no gateway addresses</a></h3>
|
|
|
|
<p>
|
|
A valid network definition can contain no IPv4 or IPv6 addresses. Such a definition
|
|
can be used for a "very private" or "very isolated" network since it will not be
|
|
possible to communicate with the virtualization host via this network. However,
|
|
this virtual network interface can be used for communication between virtual guest
|
|
systems. This works for IPv4 and <span class="since">(Since 1.0.1)</span> IPv6.
|
|
However, the new ipv6='yes' must be added for guest-to-guest IPv6
|
|
communication.
|
|
</p>
|
|
|
|
<pre>
|
|
<network ipv6='yes'>
|
|
<name>nogw</name>
|
|
<uuid>7a3b7497-1ec7-8aef-6d5c-38dff9109e93</uuid>
|
|
<bridge name="virbr2" stp="on" delay="0" />
|
|
<mac address='00:16:3E:5D:C7:9E'/>
|
|
</network></pre>
|
|
|
|
</body>
|
|
</html>
|