[Openstack] [Quantum] Metadata service route from a VM

Sylvain Bauza sylvain.bauza at digimind.com
Wed Feb 20 14:55:12 UTC 2013


Hi,

Previously using nova-network, all my VMs were having :
  # route -n
Table de routage IP du noyau
Destination     Passerelle      Genmask         Indic Metric Ref Use Iface
10.0.0.0        0.0.0.0         255.255.255.0   U     0 0        0 eth0
169.254.0.0     0.0.0.0         255.255.0.0     U     1002 0        0 eth0
0.0.0.0         10.0.0.1        0.0.0.0         UG    0 0        0 eth0

Now, this setup seems incorrect with Quantum, as the ARP query goes 
directly from the network node trying to resolve 169.254.169.254 :
[root at toto ~]# curl http://169.254.169.254/
curl: (7) couldn't connect to host

sylvain at folsom02:~$ sudo tcpdump -i qr-f76e4668-fa -nn not ip6 and not 
udp and host 169.254.169.254 -e
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on qr-f76e4668-fa, link-type EN10MB (Ethernet), capture size 
65535 bytes
15:47:46.009548 fa:16:3e:bf:0b:f6 > ff:ff:ff:ff:ff:ff, ethertype ARP 
(0x0806), length 42: Request who-has 169.254.169.254 tell 10.0.0.5, 
length 28
15:47:47.009076 fa:16:3e:bf:0b:f6 > ff:ff:ff:ff:ff:ff, ethertype ARP 
(0x0806), length 42: Request who-has 169.254.169.254 tell 10.0.0.5, 
length 28

The only way for me to fix it is to remove the 169.254.0.0/16 route on 
the VM (or for some reason I doesn't understand, by restarting 
quantum-dhcp-agent on the network node) and then L3 routing is working 
correctly :

[root at toto ~]# route del -net 169.254.0.0/16
[root at toto ~]# curl http://169.254.169.254/
1.0
2007-01-19
2007-03-01
2007-08-29
2007-10-10
2007-12-15
2008-02-01
2008-09-01
2009-04-04

sylvain at folsom02:~$ sudo tcpdump -i qg-f2397006-20 -nn not ip6 and not 
udp and host 10.0.0.5 and not port 22 -e
tcpdump: verbose output suppressed, use -v or -vv for full protocol decode
listening on qg-f2397006-20, link-type EN10MB (Ethernet), capture size 
65535 bytes
15:52:58.479234 fa:16:3e:e1:95:20 > e0:46:9a:2c:f4:7d, ethertype IPv4 
(0x0800), length 74: 10.0.0.5.55428 > 192.168.1.71.8775: Flags [S], seq 
3032859044, win 14600, options [mss 1460,sackOK,TS val 2548891 ecr 
0,nop,wscale 5], length 0
15:52:58.480987 e0:46:9a:2c:f4:7d > fa:16:3e:e1:95:20, ethertype IPv4 
(0x0800), length 74: 192.168.1.71.8775 > 10.0.0.5.55428: Flags [S.], seq 
3888257357, ack 3032859045, win 14480, options [mss 1460,sackOK,TS val 
16404712 ecr 2548891,nop,wscale 7], length 0
15:52:58.482211 fa:16:3e:e1:95:20 > e0:46:9a:2c:f4:7d, ethertype IPv4 
(0x0800), length 66: 10.0.0.5.55428 > 192.168.1.71.8775: Flags [.], ack 
1, win 457, options [nop,nop,TS val 2548895 ecr 16404712], length 0


I can't understand what's wrong with my setup. Could you help me ? I 
would have to undergo a post-up statement for all my images... :(

Thanks,
-Sylvain




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