Many thanks Chris. I just felt triggered by this closing because I remember how much pain this bug caused me while working in a data center back in the days. :)
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to dnsmasq in Ubuntu. https://bugs.launchpad.net/bugs/1006898 Title: [SRU] dnsmasq fails at leasing issues when using vlan mode Status in dnsmasq package in Ubuntu: Fix Released Status in dnsmasq source package in Precise: Won't Fix Bug description: ** Issue ** There is an issue with the way nova uses dnsmasq in VLAN mode. It starts up a single copy of dnsmasq for each vlan on the network host (or on every host in multi_host mode). The problem is in the way that dnsmasq binds to an ip address and port[2]. Both copies can respond to broadcast packet, but unicast packets can only be answered by one of the copies. In nova this means that guests from only one project will get responses to their unicast dhcp renew requests. Unicast projects from guests in other projects get ignored. What happens next is different depending on the guest os. Linux generally will send a broadcast packet out after the unicast fails, and so the only effect is a small (tens of ms) hiccup while interface is reconfigured. It can be much worse than that, however. I have seen cases where Windows just gives up and ends up with a non-configured interface. This bug was first noticed by some users of openstack who rolled their own fix. Basically, on linux, if you set the SO_BINDTODEVICE socket option, it will allow different daemons to share the port and respond to unicast packets, as long as they listen on different interfaces. I managed to communicate with Simon Kelley, the maintainer of dnsmasq and he has integrated a fix[3] for the issue in the current version[1] of dnsmaq. [3] http://thekelleys.org.uk/gitweb/?p=dnsmasq.git;a=commitdiff;h=9380ba70d67db6b69f817d8e318de5ba1e990b12 ** Development Fix ** This has been fixed in quantal with the newer version of dnmasq. ** Stable Fix ** I have backported the patch which fixes this issue, I have attached the debdiff and the buildlog. ** Test Case ** 1. Install openstack with vlan mode. 2. Watch instances loose their IP addresses. ** Regression Potential ** Minimal, most installations dont use this type of networking. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/dnsmasq/+bug/1006898/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
