[Openstack] Quantum dhcp-agent getting out of sync with multiple instance launch / termination

Gary Kotton gkotton at vmware.com
Wed Oct 9 13:50:42 UTC 2013

Which version are you using?

On 10/9/13 4:34 PM, "Markku Tavasti" <markku.tavasti at cybercom.com> wrote:

>I found out that quantum dhcp agent gets out of sync when many instances
>are launched or deleted same time. As a result, dnsmasq host-file have
>lines missing (all launched are not added), or some lines aren't removed
>when they should. When same ip is re-used, remaining extra lines aren't
>removed, but same ip has two lines, and dhcp discoveries get no response
>(no address available error on dnsmasq logs).
>Restarting quantum-dhcp-agent will get everything back to proper state,
>but running restart on cron every minute does not sound proper fix :-(
>On my test, creating 16 instances, 2-3 of them did not get line in
>host-file. When removing all those 16, 3-5 false lines were left behind.
>On instance creation I see following message on quantum-server.log:
>For every instance:
>WARNING [quantum.db.agentschedulers_db] Fail scheduling network
>{'status': u'ACTIVE', 'subnets':
>[u'e9299278-bd49-4dc8-8df1-25b034f3ecea'], 'name': u'pk_tunk2',
>'provider:physical_network': u'vlans-osprv', 'admin_state_up': True,
>'tenant_id': u'06b9c423e10741ef83877b56d7608d7f',
>'provider:network_type': u'vlan', 'router:external': False, 'shared':
>False, 'id': u'cbce52ef-58ba-4f3c-96fb-9d51bdbf32fb',
>'provider:segmentation_id': 427L}
>However, network ports get created, and seems to work?
>And most likely related to missing lines on host file on creation:
>WARNING [quantum.scheduler.dhcp_agent_scheduler] No active DHCP agents
>For termination of instances there is no warning or error messages.
>Any ideas for fixing the situation?
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