aboutsummaryrefslogtreecommitdiffstats
path: root/docs/tutorials/transparent-dhcp
diff options
context:
space:
mode:
Diffstat (limited to 'docs/tutorials/transparent-dhcp')
0 files changed, 0 insertions, 0 deletions
generated by cgit v1.2.3 (git 2.25.1) at 2025-12-14 00:06:56 +0000
d='n47' href='#n47'>47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta http-equiv="content-type" content="text/html; charset=ISO-8859-1">
  <title>Xen Configuration Syntax</title>
</head>
<body>
<center>
<h1>Xen Configuration Syntax</h1>
<br>
<!-- Version 0.1<br>2004 June 21<br> -->
Version 0.2<br>2004 July 19<br>
</center>

<h1>Xen Configuration</h1>
The Xen virtual machine creation tools provide command-line interfaces and
HTTP interfaces to creating virtual machines. Underneath all these interfaces
virtual machine configuration data is represented in a common configuration syntax
called SXP.

The SXP syntax is s-expressions (sxprs), a simple bracketed abstract syntax.
Python lists are used to represent its parsed form, with a support
api providing  access to fields and values (class xen.xend.sxp).

<h1>SXP syntax</h1>
<p>A general s-expression has the syntax:
<code><pre>
s-exp = '(' s-exp* ')' | atom | string
</pre></code>
Where an <code>atom</code> is an unquoted string, such as fred or /domain/0.
A <code>string</code> is a quoted string, supporting the usual escape sequences.
Strings support single or double quotes: 'fred 1' or "fred 2" are both accepted.
The characters ()[]&lt;&gt{} are separators.

<p>An <code>element</code> is an s-expression representing data similar to XML.
It has the form:
<code><pre>
element    = '(' name attributes? value* ')'
name       = atom
attributes = '(' '@' attribute* ')'
attribute  = '(' attrname attrval ')'
attrname   = atom
attrval    = atom | string
value      = element | atom | string
</pre></code>
The <code>name</code> is the element name (roughly indentifying its type).
The <code>attributes</code> is a list of attribute-values.
We usually prefer to avoid using attributes, and use sub-elements instead.
As in XML, any element may have the attribute <code>id</code> to give it an identifier
for later reference.

<h1>VM configuration</h1>
A vm configuration is a single SXP vm element, with subelements for
vm parameters and devices. The supported elements and their fields
are listed below.

<h2>(vm) element</h2>
The top-level element, a virtual machine configuration.
<ul>
    <li>name: string, required. Domain name.
    <li>id: int, optional, default generated. Domain unique id.
    <li>memory: int, required. Domain memory in MB.
    <li>maxmem: int, optional. Maximum domain memory in MB.
    <li>cpu: int, optional. Cpu to run on.
    <li>cpu_weight, float, optional, default 1. Cpu weight - controls share of CPU.
    <li>image: linux | netbsd | ..., required. Domain image (OS-specific element).
    <li>backend: any backend device type, optional, default none.
    <li>device: any device type, optional, repeats. Device.
    <li>restart: string, optional, default onreboot. Restart mode, one of
        <ul><li>onreboot: restart the domain when it exits with code reboot.
            <li>always: always restart the domain when it exits.
            <li>never:  never restart the domain.
        </ul>
    <li>console: int, optional, default 9600 + domain id. Console port.
</ul>

<h2>(image (linux)) element</h2>
Defines a linux kernel image and its command-line parameters.
<ul>
    <li>kernel: string, required. Kernel image file (absolute path).
    <li>root: string, optional. Root device.
    <li>ip: string, optional. IP address specifier.
    <li>ramdisk: string, optional, default none. Ramdisk file (absolute path).
    <li>args: string, optional. Extra kernel args.
</ul>

<h2>(image (netbsd)) element</h2>
Defines a netbsd kernel image and its command-line parameters.
<ul>
    <li>kernel: string, required. Kernel image file.
    <li>root: string, optional. Root device.
    <li>ip: string, optional. IP address specifier.
    <li>ramdisk: string, optional, default none. Ramdisk file.
    <li>args: string, optional. Extra kernel args.
</ul>

<h2>(backend (blkif)) element</h2>
The vm is a block device backend.
The vm can have pci devices configured.

<h2>(backend (netif)) element</h2>
The vm is a net device backend.

<h2>(device (vif)) element</h2>
Defines a virtual network interface.
<ul>
    <li>mac: string, required. Interface MAC address.
    <li>bridge: string, optional, default system-dependent. Bridge to connect to.
    <li>script: string, optional, default system-dependent. Vif script to use
        when bringing the interface up or down.
    <li>ip: IP address, optional, no default. May be repeated. An IP address
    or CIDR-format subnet the vif may use.
    <li>backend: domain name or id, optional, default 0.
    Defines the domain to use as  the backend for the interface.
</ul>

<h2>(device (vbd)) element</h2>
Defines a virtual block device.
<ul>
    <li>uname: string, required. Virtual block device id, e.g phys:hda1.
    <li>dev: string, required. Device file name in domain, e.g. xda1.
    <li>mode: string, optional, default r. Read-write mode: r | rw | w.
    <li>backend: domain name or id, optional, default 0.
     Defines the domain to use as the backend for the device.
</ul>
The uname field defines the device being exported from the block device
controller. The dev field defines the device name the vm will see.
The device is read-only unless the mode contains w.

<h2>(device (pci)) element</h2>
Defines a pci device. 
<ul>
    <li>bus: int, required. PCI bus id.
    <li>dev: int, required. PCI dev id.
    <li>func: int, required. PCI func id.
</ul>
The bus, dev or func may be given in hex,
e.g. 0xff. With no leading 0x they are interpreted as decimal.

<h2>(vnet) element</h2>
Defines the virtual networks associated with vifs (may go away soon).
Contains a list of vif elements:
<ul>
  <li>id: id of the vif being configured.
  <li>vnet: id of vnet the vif is assigned to.
</ul>

<h1>Examples</h1>
<p> A vm  with 64 MB memory, root on /dev/xda1 (mapped from /dev/hda1),
one vif with default MAC.
<code><pre>
(vm
    (name xendom1)
    (memory 64)
    (image
        (linux
            (kernel /boot/vmlinuz-2.4.26-xen)
            (ip ::::xendom1:eth0:dhcp)
            (root /dev/xda1)
            (args 'rw fastboot 4')
        )
    )
    (device (vif))
    (device (vbd (uname phy:hda1) (dev xda1) (mode w)))
)
</pre></code>

<p>A vm with 64 MB memory, NFS root, and 2 vifs on separate vnets.
<code><pre>
(vm 
   (name xendom2)
   (memory 64)
    # Define a linux image.
    (image
        (linux 
            (kernel "/boot/vmlinuz-2.4.26-xen")
            (ip     "::::xendom2:eth0:dhcp")
            (root   "/dev/nfs")
            (args   "rw fastboot nfsroot=15.144.25.79:/opt/xen/xendom2 4")
         )
    )
    # Define some vifs, with ids for use later.
    (device (vif (@ (id vif1)) (mac aa:00:00:00:00:12)))
    (device (vif (@ (id vif2)) (mac aa:00:00:00:10:12)))

     # Configure vnets. Refer to vifs by id.
     (vnet (vif (id vif1) (vnet 1))
           (vif (id vif2) (vnet 2)))

)
</pre></code>

</body>
</html>