Public bug reported: If neutron was configured to have more than one DHCP agent per network (option dhcp_agents_per_network=2), it causes dnsmasq to reject leases of others dnsmasqs, creating mess and stopping instances to boot normally.
Symptoms: Cirros (at the log): Sending discover... Sending select for 188.42.216.146... Received DHCP NAK Usage: /sbin/cirros-dhcpc <up|down> Sending discover... Sending select for 188.42.216.146... Received DHCP NAK Usage: /sbin/cirros-dhcpc <up|down> Sending discover... Sending select for 188.42.216.146... Received DHCP NAK Steps to reproduce: 1. Set up neutron with VLANs and dhcp_agents_per_network=2 option in neutron.conf 2. Set up two or more different nodes with enabled neutron-dhcp-agent 3. Create VLAN neutron network with --enable-dhcp option 4. Create instance with that network Expected behaviour: Instance recieve IP address via DHCP without problems or delays. Actual behaviour: Instance stuck in the network boot for long time. There are complains about NACKs in the logs of dhcp client. There are multiple NACKs on tcpdump on interfaces Additional analysis: It is very complex, so I attach example of two parallel tcpdumps from two dhcp namespaces in HTML format. Version: 2014.2.3 ** Affects: neutron Importance: Undecided Status: New ** Attachment added: "tcpdump transcript of the bug" https://bugs.launchpad.net/bugs/1457900/+attachment/4402420/+files/dhcp_neutron_bug.html -- You received this bug notification because you are a member of Yahoo! Engineering Team, which is subscribed to neutron. https://bugs.launchpad.net/bugs/1457900 Title: dhcp_agents_per_network > 1 cause conflicts (NACKs) from dnsmasqs (break networks) Status in OpenStack Neutron (virtual network service): New Bug description: If neutron was configured to have more than one DHCP agent per network (option dhcp_agents_per_network=2), it causes dnsmasq to reject leases of others dnsmasqs, creating mess and stopping instances to boot normally. Symptoms: Cirros (at the log): Sending discover... Sending select for 188.42.216.146... Received DHCP NAK Usage: /sbin/cirros-dhcpc <up|down> Sending discover... Sending select for 188.42.216.146... Received DHCP NAK Usage: /sbin/cirros-dhcpc <up|down> Sending discover... Sending select for 188.42.216.146... Received DHCP NAK Steps to reproduce: 1. Set up neutron with VLANs and dhcp_agents_per_network=2 option in neutron.conf 2. Set up two or more different nodes with enabled neutron-dhcp-agent 3. Create VLAN neutron network with --enable-dhcp option 4. Create instance with that network Expected behaviour: Instance recieve IP address via DHCP without problems or delays. Actual behaviour: Instance stuck in the network boot for long time. There are complains about NACKs in the logs of dhcp client. There are multiple NACKs on tcpdump on interfaces Additional analysis: It is very complex, so I attach example of two parallel tcpdumps from two dhcp namespaces in HTML format. Version: 2014.2.3 To manage notifications about this bug go to: https://bugs.launchpad.net/neutron/+bug/1457900/+subscriptions -- Mailing list: https://launchpad.net/~yahoo-eng-team Post to : yahoo-eng-team@lists.launchpad.net Unsubscribe : https://launchpad.net/~yahoo-eng-team More help : https://help.launchpad.net/ListHelp