Vnx-plugin-dhcp
DHCP Plugin
...to be completed...
Authors: David Fernández (david at dit.upm.es) Jorge Somavilla (somavilla at dit.upm.es) Miguel Ferrer (mferrer at dit.upm.es) Francisco Jose Martin (fjmarin at dit.upm.es) Fermín Galán (galan at dit.upm.es) version 2.0, September 11th, 2011
Contents
Introduction
DHCP plugin is an example VNX extension plugin designed to facilitate the configuration of DHCP in virtual machines. It provides a simple XML language to express DHCP configurations which are independent of the DHCP implementation used in the virtual machine. At present, DHCP Plugin is implemented only for ISC DHCP based servers and relays, but can be extended to support other implementations.
To use DHCP plugin in a VNX scenario, you have to add the following tag after <vm_defaults> section of <global> tag:
<extension plugin="dhcp" conf="dhcp_conf.xml" />
The plugin configuration file or PCF contains the DHCP configuration written in a XML language. Using that language the configuration of a router looks like:
...
CHANGE!!
<vm name="r1" type="quagga" subtype="lib-install">
<hostname>r1</hostname>
<password>xxxx</password>
<network area="0.0.0.0">10.0.0.0/16</network>
<passive_if>eth1</passive_if>
<binaries>
<zebra>/usr/lib/quagga/zebra</zebra>
<ospfd>/usr/lib/quagga/ospfd</ospfd>
</binaries>
</vm>
...
DHCP plugin just processes that configuration and translates it into the necessary DHCP configuration file (dhcp.conf) and manages the DHCP daemons. See the complete example below to know more about DHCP plugin capabilities.
DHCP Plugin Example Scenario
DHCP Plugin example is a simple scenario made of two routers (r1 and r2) and two hosts (h1 and h2) designed to show the capabilities of the plugin. r1 runs a DHCP server; r2 runs a DHCP relay that retransmits requests to r1; and h1 and h2 autoconfigure themselves from r1 and r2 using DHCP. This example is included in VNX distribution.
To start the scenario, just type:
cd /usr/share/vnx/plugins/examples vnx -f example_dhcp-plugin.xml -v -t
Once started, you can check that the hosts have been configured:
root@h1:~# ifconfig eth1
eth1 Link encap:Ethernet direcciónHW 02:fd:00:04:03:01
Direc. inet:10.0.1.10 Difus.:10.0.1.255 Másc:255.255.255.0
Dirección inet6: fe80::fd:ff:fe04:301/64 Alcance:Enlace
....
And the daemons are running over r1 and r2:
root@r1:~# ps uax | grep dhcpd dhcpd 841 0.0 0.9 4668 2320 ? Ss 23:28 0:00 /usr/sbin/dhcp -q -pf /var/run/dhcp-server/dhcpd.pid -cf /etc/dhcp/dhcpd.conf r2:~# ps uax | grep dhcrelay root 2110 0.0 0.7 3160 456 ? Ss 23:27 0:00 /usr/sbin/dhcrelay3 -q 10.0.0.1
To know the scenario commands made available to the user by the plugin, you can use the "exe-info" mode of VNX:
# vnx -f example_dhcp-plugin.xml --exe-info ---------------------------------------------------------------------------------- Virtual Networks over LinuX (VNX) -- http://www.dit.upm.es/vnx - vnx@dit.upm.es Version: 2.0b.894 (built on 11/09/2011_12:20) ---------------------------------------------------------------------------------- Using configuration file: /etc/vnx.conf TMP dir=/tmp VNX dir=/root/.vnx ---------------------------------------------------------------------------------- VNX exe-info mode: User-defined command sequences for scenario 'example_dhcp_plugin' ---------------------------------------------------------------------------------- stop-www Stop apache2 web server start-www Start apache2 web server Plugin 'dhcp' command sequences for scenario 'example_dhcp_plugin' ---------------------------------------------------------------------------------- dhcp-server-stop Stops DHCP servers on_shutdown Stops all DHCP daemons dhcp-relay-start Starts DHCP relays dhcp-stop Synonym of stop dhcp-start Synonym of start dhcp-client-restart Releases client IP configurations and rexecutes DHCP clients dhcp-relay-stop Stops DHCP relays restart Restarts all DHCP daemons and clients dhcp-client-start Executes DHCP clients dhcp-relay-force-reload Restarts DHCP relays using 'force-reload' stop Stops all DHCP daemons and releases client configurations dhcp-server-force-reload Restarts DHCP servers using 'force-reload' dhcp-relay-restart Restarts DHCP relays dhcp-restart Synonym of restart on_boot Creates DHCP config files and starts services dhcp-server-start Starts DHCP servers dhcp-client-stop Releases client IP configurations redoconf Creates DHCP config files dhcp-server-restart Restarts DHCP servers start Starts all DHCP daemons and clients ---------------------------------------------------------------------------------- Total time elapsed: 0 seconds
For example, you can stop the daemon in r1 with:
vnx -f example_ospf-plugin.xml -v -x ospf-stop -M r1
and edit example_ospf-plugin-conf.xml to make any change to r1 OSPF configuration (for example, change the hostname ro router1) and reload the configuration file with:
vnx -f example_ospf-plugin.xml -v -x redoconf -M r1
After 'redoconf' command you can check the changes have been made to configuration files by accessing r1 and having a look at /etc/quagga/zebra.conf and /etc/quagga/ospfd.conf files).
Finally, you can start the daemon with the new configuration with:
vnx -f example_ospf-plugin.xml -v -x ospf-start -M r1
Note: typically plugins provide the same basic 'start|stop|restart' commands with two sequence names: general (i.e. start) and specific (i.e. ospf-start). Both execute the same actions, but the specific one is used when you want to execute commands only over a specific plugin. Selecting the general one will tipically execute commands over all plugings and some user-defined commands.
Scenario Specification
<?xml version="1.0" encoding="UTF-8"?>
<!--
~~~~~~~~~~~~~~~~~~~~
VNX Sample scenarios
~~~~~~~~~~~~~~~~~~~~
Name: example_ospf-plugin
Description: Example scenario to show the use of ospf plugin. It is made of two
routers: r1 (ubuntu) and r2(uml) and two hosts: h1 (ubuntu) and h2 (uml).
This file is part of the Virtual Networks over LinuX (VNX) Project distribution.
(www: http://www.dit.upm.es/vnx - e-mail: vnx@dit.upm.es)
Departamento de Ingenieria de Sistemas Telematicos (DIT)
Universidad Politecnica de Madrid
SPAIN
-->
<vnx xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="/usr/share/xml/vnx/vnx-2.00.xsd">
<global>
<version>2.0</version>
<scenario_name>example_ospf-plugin</scenario_name>
<ssh_key>~/.ssh/id_dsa.pub</ssh_key>
<automac offset="4"/>
<!--vm_mgmt type="none" /-->
<vm_mgmt type="private" network="10.250.0.0" mask="24" offset="16">
<host_mapping />
</vm_mgmt>
<vm_defaults>
<console id="0" display="no"/>
<console id="1" display="yes"/>
</vm_defaults>
<extension plugin="ospf" conf="example_ospf-plugin-conf.xml" />
</global>
<net name="lan1" mode="virtual_bridge" />
<net name="lan2" mode="virtual_bridge" />
<net name="ptp12" mode="virtual_bridge" />
<!-- NODES -->
<vm name="r1" type="libvirt" subtype="kvm" os="linux" exec_mode="cdrom">
<filesystem type="cow">/usr/share/vnx/filesystems/rootfs_ubuntu</filesystem>
<mem>256M</mem>
<if id="1" net="lan1">
<ipv4>10.0.1.1/24</ipv4>
<ipv6>2001:db8:1::1/64</ipv6>
</if>
<if id="2" net="ptp12">
<ipv4>10.0.0.1/30</ipv4>
<ipv6>2001:db8:12::1/64</ipv6>
</if>
<forwarding type="ip" />
</vm>
<vm name="r2" type="uml" subtype="" os="" exec_mode="mconsole">
<filesystem type="cow">/usr/share/vnx/filesystems/rootfs_uml</filesystem>
<mem>64M</mem>
<kernel>/usr/share/vnx/kernels/linux</kernel>
<if id="1" net="lan2" name="fxp0">
<ipv4>10.0.2.1/24</ipv4>
<ipv6>2001:db8:2::1/64</ipv6>
</if>
<if id="2" net="ptp12" name="fxp1">
<ipv4>10.0.0.2/30</ipv4>
<ipv6>2001:db8:12::2/64</ipv6>
</if>
<forwarding type="ip" />
</vm>
<vm name="h1" type="libvirt" subtype="kvm" os="linux" exec_mode="cdrom">
<filesystem type="cow">/usr/share/vnx/filesystems/rootfs_ubuntu</filesystem>
<mem>256M</mem>
<if id="1" net="lan1">
<ipv4>10.0.1.2/24</ipv4>
<ipv6>2001:db8:1::2/64</ipv6>
</if>
<route type="ipv4" gw="10.0.1.1">default</route>
<route type="ipv6" gw="2001:db8:1::1">default</route>
</vm>
<vm name="h2" type="uml" exec_mode="mconsole">
<filesystem type="cow">/usr/share/vnx/filesystems/rootfs_uml</filesystem>
<mem>64M</mem>
<kernel>/usr/share/vnx/kernels/linux</kernel>
<if id="1" net="lan2">
<ipv4>10.0.2.2/24</ipv4>
<ipv6>2001:db8:2::2/64</ipv6>
</if>
<route type="ipv4" gw="10.0.2.1">default</route>
<route type="ipv6" gw="2001:db8:2::1">default</route>
</vm>
<host>
<hostif net="lan1">
<ipv4>10.0.1.3/24</ipv4>
<ipv6>2001:db8:1::3/64</ipv6>
</hostif>
<route type="ipv4" gw="10.0.1.1">10.0.0.0/16</route>
<route type="ipv6" gw="2001:db8:1::1">2001:db8::/32</route>
</host>
</vnx>
Plugin Configuration File (PCF)
<ospf_conf xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="/usr/share/xml/vnx/ospf.xsd">
<vm name="r1" type="quagga" subtype="lib-install">
<hostname>r1</hostname>
<password>xxxx</password>
<network area="0.0.0.0">10.0.0.0/16</network>
<passive_if>eth1</passive_if>
<binaries>
<zebra>/usr/lib/quagga/zebra</zebra>
<ospfd>/usr/lib/quagga/ospfd</ospfd>
</binaries>
</vm>
<vm name="r2" type="quagga" subtype="lib-install">
<hostname>r2</hostname>
<password>xxxx</password>
<network area="0.0.0.0">10.0.0.0/16</network>
<passive_if>eth1</passive_if>
</vm>
</ospf_conf>
