+++ This bug was initially created as a clone of Bug #1227633 +++ Description of problem: ======================= After rolling out a configuration change, we restarted neutron-dhcp-agent service, and then dnsmasq logs start flooding: DHCPNAK ... lease not found. DHCPNAK is replied by dnsmasq for all DHCPREQUEST renews from all VMs. However the MAC and IP pairs exist in host files. The log flooding increases when more and more VMs start renewing and they keep retrying until IP expire and send DHCPDISCOVER and reinit the IP. The log flooding gradually disappears when the VMs IP expire and send DHCPDISCOVER, to which dnsmasq respond DHCPOFFER properly. Analysis: ========= I noticed that option --leasefile-ro is used in dnsmasq command when started by neutron dhcp-agent. According to dnsmasq manual, this option should be used together with --dhcp-script to customize the lease database. However, the option --dhcp-script was removed when fixing bug 1202392. Because of this, dnsmasq will not save lease information in persistent storage, and when it is restarted, lease information is lost. Solution: ========= Simply replace --leasefile-ro by --dhcp-leasefile=<path to dhcp runtime files>/lease would solve the problem. (patch attached)
Tested on Rhel7.1 puddle from 2015-08-13.1 dhcp-common-4.2.5-36.el7.x86_64 dhcp-libs-4.2.5-36.el7.x86_64 openstack-neutron-2014.2.3-9.el7ost.noarch openstack-neutron-common-2014.2.3-9.el7ost.noarch python-neutronclient-2.3.9-1.el7ost.noarch python-neutron-2014.2.3-9.el7ost.noarch openstack-neutron-openvswitch-2014.2.3-9.el7ost.noarch The DHCP messages from /var/log/messages file of the agents. Agent#1: Aug 17 06:23:48 networker2 dnsmasq-dhcp[21035]: DHCPDISCOVER(tap29cff8bc-cc) fa:16:3e:a8:b9:1a Aug 17 06:23:48 networker2 dnsmasq-dhcp[21035]: DHCPOFFER(tap29cff8bc-cc) 80.80.80.5 fa:16:3e:a8:b9:1a Aug 17 06:23:48 networker2 dnsmasq-dhcp[21035]: DHCPREQUEST(tap29cff8bc-cc) 80.80.80.5 fa:16:3e:a8:b9:1a Aug 17 06:23:48 networker2 dnsmasq-dhcp[21035]: DHCPACK(tap29cff8bc-cc) 80.80.80.5 fa:16:3e:a8:b9:1a host-80-80-80-5 Agent#2 Aug 17 06:23:49 networker1 dnsmasq-dhcp[28502]: DHCPDISCOVER(tap6b8cb71c-b4) fa:16:3e:a8:b9:1a Aug 17 06:23:49 networker1 dnsmasq-dhcp[28502]: DHCPOFFER(tap6b8cb71c-b4) 80.80.80.5 fa:16:3e:a8:b9:1a
Since the problem described in this bug report should be resolved in a recent advisory, it has been closed with a resolution of ERRATA. For information on the advisory, and where to find the updated files, follow the link below. If the solution does not work for you, open a new bug report. https://rhn.redhat.com/errata/RHSA-2015-1680.html