[Openstack] What's the package flow in vlan mode when ping the floating ip between vms.

Narayan Desai narayan.desai at gmail.com
Wed Apr 10 00:53:27 UTC 2013


This will depend on whether the VMs are in the same tenant network or
not. Assuming they are on the same L2 and L3 network, then the packets
will transit either the linux bridge, or openvswitch, depending on how
you have things configured. Note that network filtering rules will be
processed on this path in some cases.

If you are talking about flows between VMs that are on different
tenant networks (both ends using RFC1918 addresses), nova-network
would setup gateways for each network in the host, and it should be
routing, i think. (this is supposition on my part -- we've only done
some basic experiments with multi-host)
 -nld

On Tue, Apr 9, 2013 at 7:41 PM, Lei Zhang <zhang.lei.fly at gmail.com> wrote:
> Hi JuanFra,
>
> I read this article. But It doesn't explain what I concern.
> What I want to know is that what's the packet flow when ping the floating ip
> between the VMs which located in the same physical machine?
>
>
> On Tue, Apr 9, 2013 at 9:56 PM, JuanFra Rodriguez Cardoso
> <juanfra.rodriguez.cardoso at gmail.com> wrote:
>>
>> Could this Mirantis' post help you?
>>
>> http://www.mirantis.com/blog/vlanmanager-network-flow-analysis/
>>
>> ---
>> JuanFra
>>
>>
>> 2013/4/9 Lei Zhang <zhang.lei.fly at gmail.com>
>>>
>>> I am using: Folsom, nova-network, vlanManage, multi_host=ture
>>>
>>> I want to know what's the package flow between the vms which located in
>>> the same physical machine.
>>>
>>> Here is the typology. I want to know want happen if I ping 192.168.3.47
>>> in vm7.
>>>
>>> When the NAT is applied?
>>>
>>>    |vm: fixed: 10.0.104.5, floating:
>>> 192.168.3.56|-----|vnet15|----|br104|----|vnet14|----| vm7: fixed:
>>> 10.0.104.6, floating: 192.168.3.57|
>>>
>>> if the net.bridge.bridge-nf-call-iptables=0, I can not see the NAT
>>> properly.
>>>
>>> [root at openstack-node1 ~]# tcpdump -i vnet14 -l -ne icmp -v
>>> tcpdump: WARNING: vnet14: no IPv4 address assigned
>>> tcpdump: listening on vnet14, link-type EN10MB (Ethernet), capture size
>>> 65535 bytes
>>> 17:11:10.275818 fa:16:3e:3e:ab:8f > fa:16:3e:72:8f:b4, ethertype IPv4
>>> (0x0800), length 98: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto
>>> ICMP (1), length 84)
>>>     10.0.104.6 > 192.168.3.56: ICMP echo request, id 31090, seq 1, length
>>> 64
>>> 17:11:10.277546 fa:16:3e:22:31:09 > fa:16:3e:3e:ab:8f, ethertype IPv4
>>> (0x0800), length 98: (tos 0x0, ttl 64, id 64703, offset 0, flags [none],
>>> proto ICMP (1), length 84)
>>>     10.0.104.5 > 10.0.104.6: ICMP echo reply, id 31090, seq 1, length 64
>>>
>>> When net.bridge.bridge-nf-call-iptables=1, I found the NAT properly. But
>>> I also found it is said the bridge filter should be disabled in
>>> http://docs.openstack.org/trunk/openstack-compute/admin/content/network-troubleshooting.html.
>>> Is this true?
>>>
>>> [root at openstack-node1 ~]# tcpdump -i vnet14 -l -ne icmp -v
>>> tcpdump: WARNING: vnet14: no IPv4 address assigned
>>> tcpdump: listening on vnet14, link-type EN10MB (Ethernet), capture size
>>> 65535 bytes
>>> 17:13:40.507577 fa:16:3e:3e:ab:8f > fa:16:3e:72:8f:b4, ethertype IPv4
>>> (0x0800), length 98: (tos 0x0, ttl 64, id 0, offset 0, flags [DF], proto
>>> ICMP (1), length 84)
>>>     10.0.104.6 > 192.168.3.56: ICMP echo request, id 42098, seq 1, length
>>> 64
>>> 17:13:40.508034 fa:16:3e:22:31:09 > fa:16:3e:3e:ab:8f, ethertype IPv4
>>> (0x0800), length 98: (tos 0x0, ttl 64, id 64704, offset 0, flags [none],
>>> proto ICMP (1), length 84)
>>>     192.168.3.56 > 10.0.104.6: ICMP echo reply, id 42098, seq 1, length
>>> 64
>>>
>>> --
>>> Lei Zhang
>>>
>>> Blog: http://jeffrey4l.github.com
>>> twitter/weibo: @jeffrey4l
>>>
>>> _______________________________________________
>>> Mailing list: https://launchpad.net/~openstack
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>>>
>>
>
>
>
> --
> Lei Zhang
>
> Blog: http://jeffrey4l.github.com
> twitter/weibo: @jeffrey4l
>
> _______________________________________________
> Mailing list: https://launchpad.net/~openstack
> Post to     : openstack at lists.launchpad.net
> Unsubscribe : https://launchpad.net/~openstack
> More help   : https://help.launchpad.net/ListHelp
>




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