Recently I needed to implement functionality to operate a DHCP relay instead of dnsmasq's DHCP server on the virtual networks managed by libvirt.
The primary benefit of operating a relay is that the central DHCP and DNS servers for the physical network can manage IP address allocation and hostname resolution for the entire network and, potentially, expose VMs via hostname and IP address on the public network too, as well as being able to monitor VM instance creation for resource planning. I originally implemented this functionality on libvirt 0.9.8 included with Ubuntu 12.04 as a hack to simply disable dnsmasq entirely and use dhcp-helper[1] (the DHCP relay written by Simon Kelley, author of dnsmaq) although I've constructed it so that another relay-agent could be used. After proving it works well I've reworked the code on the current libvirt master branch. If it's thought to be of use to the project please let me know. [1] http://www.thekelleys.org.uk/dhcp-helper/ The following changes since commit 34f1a618a5c4507f27f3f467b723c9119c1db3c7: conf: Avoid leaking of RNG device definition (2013-02-25 22:31:11 +0100) are available in the git repository at: git://github.com/iam-TJ/libvirt.git dhcp_relay_network for you to fetch changes up to dfc0609403106712b205e60b53b29dc850cad68d: docs: Describe the <dhcp> 'enable' and 'relay' attributes (2013-02-27 20:35:06 +0000) ---------------------------------------------------------------- TJ (10): conf: DHCP - add state for DHCP Relay and On/Off switch conf: Network - add ability to read/write XML DHCP state conf: Network - add pointers to enabled virNetworkIpDef DHCP settings conf: Network - keep track of active DHCP stanza in virNetworkDef network: Bridge - use IPv4 and IPv6 active DHCP stanza pointers network: Bridge - Add support for a DHCP Relay Agent network: Bridge - don't offer dnsmasq DHCP services when DHCP relay is enabled configure: Add DHCPRELAY to the set of external program definitions Add copyright attribution for DHCP relay functionality docs: Describe the <dhcp> 'enable' and 'relay' attributes configure.ac | 4 +++ docs/formatnetwork.html.in | 22 +++++++++++++- src/conf/network_conf.c | 36 +++++++++++++++++++--- src/conf/network_conf.h | 7 +++++ src/network/bridge_driver.c | 215 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++------------------------------- 5 files changed, 229 insertions(+), 55 deletions(-) -- libvir-list mailing list libvir-list@redhat.com https://www.redhat.com/mailman/listinfo/libvir-list
