[Openstack] can anybody help to explain how the packet of ping shoule be forwarded from vm
Sam Lee
lixq2000 at gmail.com
Tue Sep 23 07:51:37 UTC 2014
I think routing is in step 4。 The packet shoule be processed by eth1 based
on routing table. in fact eth0 process it. this is what I am puzzled
2014-09-23 15:47 GMT+08:00 Sam Lee <lixq2000 at gmail.com>:
> Can you explain it more detail? when the routing table is used?
>
> 2014-09-23 15:39 GMT+08:00 严超 <yanchao727 at gmail.com>:
>
>> I think that path should depends on your route table. You can modify
>> route table to take some tests.
>>
>> *Best Regards！*
>>
>>
>> *Chao Yan--------------**My twitter：Andy Yan @yanchao727
>> <https://twitter.com/yanchao727>*
>>
>>
>> *My Weibo：http://weibo.com/herewearenow
>> <http://weibo.com/herewearenow>--------------*
>>
>> 2014-09-23 15:21 GMT+08:00 Sam Lee <lixq2000 at gmail.com>:
>>
>>> I have tracked the packets using tcpdump, and it shows that the eth0
>>> process the packets. When a floating ip is added on instance, eth1 process
>>> the packets.
>>>
>>> 2014-09-23 15:18 GMT+08:00 严超 <yanchao727 at gmail.com>:
>>>
>>>> Yes, that's what I suggest. You can use tcpdump to track packages as
>>>> well.
>>>>
>>>> *Best Regards！*
>>>>
>>>>
>>>> *Chao Yan--------------**My twitter：Andy Yan @yanchao727
>>>> <https://twitter.com/yanchao727>*
>>>>
>>>>
>>>> *My Weibo：http://weibo.com/herewearenow
>>>> <http://weibo.com/herewearenow>--------------*
>>>>
>>>> 2014-09-23 15:13 GMT+08:00 Sam Lee <lixq2000 at gmail.com>:
>>>>
>>>>> I am not sure you are right or not. Bridge is a virtual switch, if
>>>>> we want to communicate outside world using bridge, we must attach a
>>>>> physical devices to bridge. eth0 is just the device.
>>>>>
>>>>> 2014-09-23 15:04 GMT+08:00 严超 <yanchao727 at gmail.com>:
>>>>>
>>>>>> eth0 is virtualized as br100 , as your command show:
>>>>>>
>>>>>> 2: eth0: mtu 1500 qdisc pfifo_fast *master br100 state UP* qlen 1000
>>>>>> link/ether 00:1e:67:6a:8b:c9 brd ff:ff:ff:ff:ff:ff
>>>>>> inet6 fe80::21e:67ff:fe6a:8bc9/64 scope link
>>>>>> valid_lft forever preferred_lft forever
>>>>>>
>>>>>> So I think packages would be handled by eth0. Right?
>>>>>>
>>>>>>
>>>>>> *Best Regards！*
>>>>>>
>>>>>>
>>>>>> *Chao Yan--------------**My twitter：Andy Yan @yanchao727
>>>>>> <https://twitter.com/yanchao727>*
>>>>>>
>>>>>>
>>>>>> *My Weibo：http://weibo.com/herewearenow
>>>>>> <http://weibo.com/herewearenow>--------------*
>>>>>>
>>>>>> 2014-09-23 14:33 GMT+08:00 Sam Lee <lixq2000 at gmail.com>:
>>>>>>
>>>>>>> I set up an openstack environment using nova-network with multi_host
>>>>>>> mode.
>>>>>>>
>>>>>>> created network info as below,
>>>>>>>
>>>>>>> root at ubuntu:~# nova network-show e77b754d-5a89-41fd-8c82-69051e69c4ed
>>>>>>> +---------------------+--------------------------------------+
>>>>>>> | Property | Value |
>>>>>>> +---------------------+--------------------------------------+
>>>>>>> | bridge | br100 |
>>>>>>> | vpn_public_port | None |
>>>>>>> | dhcp_start | 172.16.10.202 |
>>>>>>> | bridge_interface | eth0 |
>>>>>>> | updated_at | None |
>>>>>>> | id | e77b754d-5a89-41fd-8c82-69051e69c4ed |
>>>>>>> | cidr_v6 | None |
>>>>>>> | deleted_at | None |
>>>>>>> | gateway | 172.16.10.1 |
>>>>>>> | rxtx_base | None |
>>>>>>> | label | private |
>>>>>>> | priority | None |
>>>>>>> | project_id | None |
>>>>>>> | vpn_private_address | None |
>>>>>>> | deleted | 0 |
>>>>>>> | vlan | None |
>>>>>>> | broadcast | 172.16.10.207 |
>>>>>>> | netmask | 255.255.255.248 |
>>>>>>> | injected | False |
>>>>>>> | cidr | 172.16.10.200/29 |
>>>>>>> | vpn_public_address | None |
>>>>>>> | multi_host | True |
>>>>>>> | dns2 | None |
>>>>>>> | created_at | 2014-09-11T07:58:13.000000 |
>>>>>>> | host | None |
>>>>>>> | gateway_v6 | None |
>>>>>>> | netmask_v6 | None |
>>>>>>> | dns1 | 8.8.4.4 |
>>>>>>> +---------------------+--------------------------------------+
>>>>>>> Note: 172.16.10.1 is the physical gateway
>>>>>>>
>>>>>>> route info of the host as below：
>>>>>>>
>>>>>>> Kernel IP routing table
>>>>>>> Destination Gateway Genmask Flags Metric Ref Use Iface
>>>>>>> 0.0.0.0 172.16.10.1 0.0.0.0 UG 100 0 0 eth1
>>>>>>> 10.10.100.0 0.0.0.0 255.255.255.0 U 0 0 0 br100
>>>>>>> 172.16.10.0 0.0.0.0 255.255.255.0 U 0 0 0 eth1
>>>>>>> 172.16.10.200 0.0.0.0 255.255.255.248 U 0 0 0 br100
>>>>>>>
>>>>>>> three instances has been created as below,
>>>>>>>
>>>>>>> root at ubuntu:~# nova list
>>>>>>> +--------------------------------------+-------+--------+-----------------------+
>>>>>>> | ID | Name | Status | Networks |
>>>>>>> +--------------------------------------+-------+--------+-----------------------+
>>>>>>> | 5867fa88-de5c-4656-9811-5c86128b786b | test3 | ACTIVE | private=172.16.10.202 |
>>>>>>> | 272f8d4f-f924-488b-855f-7f53a2372708 | test4 | ACTIVE | private=172.16.10.204 |
>>>>>>> | aec01738-996f-42dc-a921-1c859c79ffed | test5 | ACTIVE | private=172.16.10.205 |
>>>>>>> +--------------------------------------+-------+--------+-----------------------+
>>>>>>>
>>>>>>> ip info of host:
>>>>>>>
>>>>>>> root at ubuntu:~# ip a
>>>>>>> 1: lo: mtu 16436 qdisc noqueue state UNKNOWN
>>>>>>> link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
>>>>>>> inet 127.0.0.1/8 scope host lo
>>>>>>> inet 169.254.169.254/32 scope link lo
>>>>>>> inet6 ::1/128 scope host
>>>>>>> valid_lft forever preferred_lft forever
>>>>>>> 2: eth0: mtu 1500 qdisc pfifo_fast master br100 state UP qlen 1000
>>>>>>> link/ether 00:1e:67:6a:8b:c9 brd ff:ff:ff:ff:ff:ff
>>>>>>> inet6 fe80::21e:67ff:fe6a:8bc9/64 scope link
>>>>>>> valid_lft forever preferred_lft forever
>>>>>>> 3: eth1: mtu 1500 qdisc pfifo_fast state UP qlen 1000
>>>>>>> link/ether 00:1e:67:6a:8b:c8 brd ff:ff:ff:ff:ff:ff
>>>>>>> inet 172.16.10.16/24 brd 172.16.10.255 scope global eth1
>>>>>>> inet6 fe80::21e:67ff:fe6a:8bc8/64 scope link
>>>>>>> valid_lft forever preferred_lft forever
>>>>>>> 5: br100: mtu 1500 qdisc noqueue state UP
>>>>>>> link/ether 00:1e:67:6a:8b:c9 brd ff:ff:ff:ff:ff:ff
>>>>>>> inet 172.16.10.203/29 brd 172.16.10.207 scope global br100
>>>>>>> inet 10.10.100.52/24 brd 10.10.100.255 scope global br100
>>>>>>> inet6 fe80::44c7:b4ff:fe0c:3f/64 scope link
>>>>>>> valid_lft forever preferred_lft forever
>>>>>>> 6: vnet0: mtu 1500 qdisc pfifo_fast master br100 state UNKNOWN qlen 500
>>>>>>> link/ether fe:16:3e:0f:03:49 brd ff:ff:ff:ff:ff:ff
>>>>>>> inet6 fe80::fc16:3eff:fe0f:349/64 scope link
>>>>>>> valid_lft forever preferred_lft forever
>>>>>>> 7: vnet1: mtu 1500 qdisc pfifo_fast master br100 state UNKNOWN qlen 500
>>>>>>> link/ether fe:16:3e:b3:d8:a1 brd ff:ff:ff:ff:ff:ff
>>>>>>> inet6 fe80::fc16:3eff:feb3:d8a1/64 scope link
>>>>>>> valid_lft forever preferred_lft forever
>>>>>>> 8: vnet2: mtu 1500 qdisc pfifo_fast master br100 state UNKNOWN qlen 500
>>>>>>> link/ether fe:16:3e:0e:7a:0d brd ff:ff:ff:ff:ff:ff
>>>>>>> inet6 fe80::fc16:3eff:fe0e:7a0d/64 scope link
>>>>>>> valid_lft forever preferred_lft forever
>>>>>>>
>>>>>>> mac table of br100:
>>>>>>>
>>>>>>> root at ubuntu:~# brctl showmacs br100
>>>>>>> port no mac addr is local? ageing timer
>>>>>>> 1 00:0c:29:27:9d:7e no 16.79
>>>>>>> 1 00:0c:29:27:9d:88 no 5.49
>>>>>>> 1 00:0c:29:58:9a:64 no 31.86
>>>>>>> 1 00:0c:29:f3:cf:7b no 21.28
>>>>>>> 1 00:12:7f:7d:37:a1 no 35.54
>>>>>>> 1 00:14:5e:ac:7c:b5 no 26.20
>>>>>>> 1 00:14:5e:e8:03:d1 no 13.31
>>>>>>> 1 00:14:f2:a8:00:81 no 1.11
>>>>>>> 1 00:1e:67:45:85:ad no 14.02
>>>>>>> 1 00:1e:67:64:ed:c9 no 10.10
>>>>>>> 1 00:1e:67:64:ee:a5 no 9.38
>>>>>>> 1 00:1e:67:6a:8b:c9 yes 0.00
>>>>>>> 1 00:1e:67:97:17:ee no 52.97
>>>>>>> 1 52:54:00:01:40:23 no 10.72
>>>>>>> 1 52:54:00:1c:71:3d no 5.50
>>>>>>> 1 52:54:00:47:9c:ee no 8.70
>>>>>>> 1 52:54:00:b8:aa:45 no 9.79
>>>>>>> 1 52:54:00:ee:60:44 no 7.61
>>>>>>> 1 5c:f3:fc:00:0e:da no 56.27
>>>>>>> 1 5c:f3:fc:00:ad:02 no 1.13
>>>>>>> 1 6c:ae:8b:51:49:12 no 0.64
>>>>>>> 1 8a:62:65:05:8d:02 no 5.38
>>>>>>> 1 ae:2a:9d:74:11:03 no 155.47
>>>>>>> 1 e4:1f:13:75:47:e0 no 8.24
>>>>>>> 1 e4:1f:13:fc:a8:21 no 176.11
>>>>>>> 1 fa:16:3e:00:c8:ce no 0.38
>>>>>>> 1 fa:16:3e:05:61:a3 no 4.29
>>>>>>> 4 fa:16:3e:0e:7a:0d no 11.35
>>>>>>> 2 fa:16:3e:0f:03:49 no 9.90
>>>>>>> 1 fa:16:3e:2c:6c:55 no 24.90
>>>>>>> 1 fa:16:3e:2d:f0:f0 no 7.40
>>>>>>> 1 fa:16:3e:3b:35:e1 no 27.88
>>>>>>> 1 fa:16:3e:3f:1a:0c no 9.18
>>>>>>> 1 fa:16:3e:49:d6:54 no 10.57
>>>>>>> 1 fa:16:3e:4a:47:6e no 13.07
>>>>>>> 1 fa:16:3e:61:d5:0c no 24.14
>>>>>>> 1 fa:16:3e:6b:89:c1 no 25.96
>>>>>>> 1 fa:16:3e:85:80:df no 3.74
>>>>>>> 1 fa:16:3e:8d:a4:da no 28.20
>>>>>>> 1 fa:16:3e:9f:bb:0c no 13.65
>>>>>>> 1 fa:16:3e:a6:88:1d no 24.17
>>>>>>> 3 fa:16:3e:b3:d8:a1 no 6.07
>>>>>>> 1 fa:16:3e:c8:42:0d no 27.80
>>>>>>> 1 fa:16:3e:ca:a8:8e no 4.70
>>>>>>> 1 fa:16:3e:e8:a7:9b no 27.31
>>>>>>> 4 fe:16:3e:0e:7a:0d yes 0.00
>>>>>>> 2 fe:16:3e:0f:03:49 yes 0.00
>>>>>>> 3 fe:16:3e:b3:d8:a1 yes 0.00
>>>>>>>
>>>>>>> arp table of instance test5:
>>>>>>>
>>>>>>> [root at test5 ~]# arp -a
>>>>>>> ? (172.16.10.203) at 00:1e:67:6a:8b:c9 [ether] on eth0
>>>>>>> ? (172.16.10.1) at 00:12:7f:7d:37:a1 [ether] on eth0
>>>>>>>
>>>>>>> route info of instance test5
>>>>>>>
>>>>>>> [root at test5 ~]# route -n
>>>>>>> Kernel IP routing table
>>>>>>> Destination Gateway Genmask Flags Metric Ref Use Iface
>>>>>>> 172.16.10.1 0.0.0.0 255.255.255.255 UH 0 0 0 eth0
>>>>>>> 172.16.10.200 0.0.0.0 255.255.255.248 U 1 0 0 eth0
>>>>>>> 192.168.122.0 0.0.0.0 255.255.255.0 U 0 0 0 virbr0
>>>>>>> 0.0.0.0 172.16.10.1 0.0.0.0 UG 0 0 0 eth0
>>>>>>>
>>>>>>> I ping www.sina.com.cn in instances test5(172.16.10.205)
>>>>>>>
>>>>>>> [root at test5 ~]# ping www.sina.com.cn
>>>>>>> PING ara.sina.com.cn (58.63.236.35) 56(84) bytes of data.
>>>>>>> 64 bytes from 58.63.236.35: icmp_seq=1 ttl=49 time=38.4 ms
>>>>>>> 64 bytes from 58.63.236.35: icmp_seq=2 ttl=49 time=38.5 ms
>>>>>>> 64 bytes from 58.63.236.35: icmp_seq=3 ttl=49 time=38.2 ms
>>>>>>> ^C
>>>>>>> --- ara.sina.com.cn ping statistics ---
>>>>>>> 3 packets transmitted, 3 received, 0% packet loss, time 2436ms
>>>>>>> rtt min/avg/max/mdev = 38.259/38.427/38.536/0.256 ms
>>>>>>>
>>>>>>> In my option, the packet will go through as follow,
>>>>>>> 1. vm eth0
>>>>>>> 2. br100
>>>>>>> 3. according the mac table of switch br100， the packet will go
>>>>>>> through to port 1
>>>>>>>
>>>>>>> the next step has always puzzled me
>>>>>>> 4. the packet arrived at host eth0. Once the packet arrived eth0, it
>>>>>>> will be processed by iptables chains, INPUT, PREROUTING, kernel routing,
>>>>>>> OUTPUT and so on. the destination address is 58.63.236.35, based on the
>>>>>>> kernel routing table, the packet will be processed by eth1. *In
>>>>>>> fact, eth0 processes it.*can anyone explain why??
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> Thanks in advance.
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Mailing list:
>>>>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
>>>>>>> Post to : openstack at lists.openstack.org
>>>>>>> Unsubscribe :
>>>>>>> http://lists.openstack.org/cgi-bin/mailman/listinfo/openstack
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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