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Possible delay in Quantum GRE and flows

asked 2013-05-02 09:14:53 -0500

colo90 gravatar image

updated 2014-03-05 01:29:51 -0500

darragh-oreilly gravatar image

Hi All, i have a brand new install of Grizzly on Ubuntu 12.04 with network_type gre I have high RTT for the first packets when i'm trying to ping the VM My VM has a Private IP: 192.168.178.2 natted on Public IP: 185.21.172.18 When i try to reach public IP, i get this output :

PING 185.21.172.18 (185.21.172.18) 56(84) bytes of data.
64 bytes from 185.21.172.18: icmp_req=1 ttl=58 time=6546 ms
64 bytes from 185.21.172.18: icmp_req=2 ttl=58 time=5546 ms
64 bytes from 185.21.172.18: icmp_req=3 ttl=58 time=4546 ms
64 bytes from 185.21.172.18: icmp_req=4 ttl=58 time=3546 ms
64 bytes from 185.21.172.18: icmp_req=5 ttl=58 time=2546 ms
64 bytes from 185.21.172.18: icmp_req=6 ttl=58 time=1546 ms
64 bytes from 185.21.172.18: icmp_req=7 ttl=58 time=546 ms
64 bytes from 185.21.172.18: icmp_req=8 ttl=58 time=2.52 ms
64 bytes from 185.21.172.18: icmp_req=9 ttl=58 time=2.50 ms
64 bytes from 185.21.172.18: icmp_req=10 ttl=58 time=2.73 ms
64 bytes from 185.21.172.18: icmp_req=11 ttl=58 time=2.41 ms
64 bytes from 185.21.172.18: icmp_req=12 ttl=58 time=2.67 ms

Seems that the flows are create with some delay. The output of the command : ovs-dpctl dump-flows br-int | grep 212.29.130 as soon as i start the ping is blank when ping start work the flows are created succesfull

ovs-dpctl dump-flows br-int | grep 212.29.130

in_port(80),eth(src=fa:16:3e:99:1b:4c,dst=fa:16:3e:da:15:4c),eth_type(0x0800),ipv4(src=212.29.130.12,dst=192.168.178.2,proto=1,tos=0,ttl=58,frag=no),icmp(type=8,code=0), packets:7, bytes:686, used:0.276s, actions:push_vlan(vid=11,pcp=0),65

in_port(65),eth(src=fa:16:3e:da:15:4c,dst=fa:16:3e:99:1b:4c),eth_type(0x8100),vlan(vid=11,pcp=0),encap(eth_type(0x0800),ipv4(src=192.168.178.2,dst=212.29.130.12,proto=1,tos=0,ttl=64,frag=no),icmp(type=0,code=0)), packets:1, bytes:98, used:0.276s, actions:pop_vlan,80

if i try to ping again the VM (when the flow is created) ping works properly, otherwise latency problems occurs again.

Am I doing something wrong?Can anyone help with this? if you need other information, don't hesitate to ask Thanks

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answered 2013-05-02 14:41:22 -0500

darragh-oreilly gravatar image

just to confirm, the 1st ping request packet is reaching br-int quickly - ie it is not getting slowed down outside openstack/quantum and taking 6.5 seconds to reach the quantum router gateway?

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Hello, we have exactly same issue. I tried to enable STP on br-int, but it didn't help. I found out, that we have port inconsistency between ovs config.db and real VM ports. Some ports which are in ovs config.db are not created. We have about 80 instances on 3 nodes. We see thousands of dropped messages in ovs-vswitchd.log each few seconds. Does anyone know, how to find out what messages are dropped?

kmadac gravatar imagekmadac ( 2014-03-04 13:56:52 -0500 )edit

I'm not sure. You could try clearing/reseting the local ovs db - not sure how, but shouldn't be too hard. Also the OP says a better CPU fixed it. Maybe have a look at the load from vswitchd. OVS v2 now has multithreaded support - that might help.

darragh-oreilly gravatar imagedarragh-oreilly ( 2014-03-05 01:37:55 -0500 )edit

Thanks for reply. Today I upgraded OVS to 1.10.2 and latency is gone.

kmadac gravatar imagekmadac ( 2014-03-05 10:16:21 -0500 )edit

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Asked: 2013-05-02 09:14:53 -0500

Seen: 123 times

Last updated: Mar 05 '14