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

Sylvain Bauza sylvain.bauza at digimind.com
Thu Feb 21 10:33:20 UTC 2013


Anyone ?
I found the reason why a 'quantum-dhcp-agent restart' is fixing the 
route, this is because the lease is DHCPNACK'd at next client refresh 
and the VM is getting a fresh new configuration excluding 169.254.0.0/16 
route.

Community, I beg you to confirm the 169.254.0.0/16 route should *not* be 
pushed to VMs, and 169.254.169.254/32 should be sent thru the default 
route (ie. provider router internal IP).
If it's the case, I'll update all my images to remove that route. If 
not, something is wrong with my Quantum setup that I should fix.

Thanks,
-Sylvain

Le 20/02/2013 15:55, Sylvain Bauza a écrit :
> 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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