[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 07:21:22 UTC 2014
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.
>>>>
>>>>
>>>> _______________________________________________
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>>>>
>>>>
>>>
>>
>
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