On 05/30/2012 06:00 AM, Cleber Rosa wrote: > First, let me see If I understand this correctly: somehow the > combination of tcpdump + the network config/stack in an rhev-h/ovirt > node takes about 1 hour to get an IP? > > This reminds me of something I thought a while ago, when we decided to > go with the libvirt private bridge as the default network for the KVM > test: the dnsmasq daemon, which answers the DHCP requests, can be easily > queried for leases, which can resolve the MAC -> IP for guests. > > That way, we could drop the requirement and the way we use tcpdump, > which IMHO is as a nice little hack that we could live without. >
Unfortunately/fortunately tcpdump will probably have to stay. With physical device bridges, dnsmasq is not used, rather a more centralized DHCP server is used. Also consider that libvirt (and tests) can start/stop/migrate VMs on other hosts. So we do need a way of listening for DHCP broadcasts when static addresses are not used. Another possibly viable alternative is to monitor the hosts arp cache. I'm not sure if it's part of the ipv4 standard or not, but hosts generally issue a gratuitous arp when they bring up an interface. The down-side here is nearly the same as tcpdump/dhcp in that some bridge/switch setups may not pass the arp through to all hosts. So, as ugly as it is, I think the tcpdump solution is the best, simple hack we have. -- Chris Evich, RHCA, RHCE, RHCDS, RHCSS Quality Assurance Engineer e-mail: cevich + `@' + redhat.com o: 1-888-RED-HAT1 x44214 _______________________________________________ Autotest mailing list Autotest@test.kernel.org http://test.kernel.org/cgi-bin/mailman/listinfo/autotest
