[Openstack] CentOS Network Create problem

Remo Mattei Remo at italy1.com
Wed Jan 15 20:04:44 UTC 2014


Hi just a quick not make sure you safe your iptables rules before you do iptables -F. 

Remo 

On Jan 15, 2014, at 10:58 AM, Bhattacharjee, Arindam (Arindam) <arindam.bhattacharjee at alcatel-lucent.com> wrote:

> 1. Check brctl showmacs br100
> If you see the mac address of the vnic of VM by lggiing into VM - do ifconfig to compare the mac address.
> 
> 2. Then check Firwall configs in both Host and VM. Check stopping FW service and doing iptables -F.
> 
> 3. Do tcpdump -i -e vnet0  while sening ping to the GW from VM.
> 
> Those would give you some clue to what's going on.
> 
> -Arindam
> 
> 
> -----Original Message-----
> From: Dimitri Maziuk [mailto:dmaziuk at bmrb.wisc.edu] 
> Sent: Wednesday, January 15, 2014 1:30 PM
> To: openstack at lists.openstack.org
> Subject: Re: [Openstack] CentOS Network Create problem
> 
> On 01/15/2014 08:23 AM, Georgios Dimitrakakis wrote:
>> Hi again...Long day with OpenStack today...
>> 
>> It seems that the problem with the br100 interface has been solved 
>> partially since I can launch an instance but I am not able to ssh nor 
>> ping the machine (although I have configured the security group rules).
> 
> Here's what I have on a working node with 2 instances running. Ignore virbr0, it's created by libvirt, vnet0 & 1 are the openstack instances:
> 
> # brctl show
> bridge name     bridge id               STP enabled     interfaces
> br100           8000.003048c53032       no              eth0
>                                                        vnet0
>                                                        vnet1
> virbr0          8000.52540025455f       yes             virbr0-nic
> 
> # ip a
> 1: lo: <LOOPBACK,UP,LOWER_UP> 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
>    inet6 ::1/128 scope host
>       valid_lft forever preferred_lft forever
> 2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 1000
>    link/ether 00:30:48:c5:30:32 brd ff:ff:ff:ff:ff:ff
>    inet6 fe80::230:48ff:fec5:3032/64 scope link
>       valid_lft forever preferred_lft forever
> 3: eth1: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 1000
>    link/ether 00:30:48:c5:30:33 brd ff:ff:ff:ff:ff:ff
> 4: br100: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
>    link/ether 00:30:48:c5:30:32 brd ff:ff:ff:ff:ff:ff
>    inet X.X.X.X/25 brd X.X.X.X scope global br100
>    inet6 fe80::230:48ff:fec5:3032/64 scope link
>       valid_lft forever preferred_lft forever
> 5: virbr0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UNKNOWN
>    link/ether 52:54:00:25:45:5f brd ff:ff:ff:ff:ff:ff
>    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
> 6: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN qlen 500
>    link/ether 52:54:00:25:45:5f brd ff:ff:ff:ff:ff:ff
> 10: vnet0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 500
>    link/ether fe:16:3e:48:30:5c brd ff:ff:ff:ff:ff:ff
>    inet6 fe80::fc16:3eff:fe48:305c/64 scope link
>       valid_lft forever preferred_lft forever
> 38: vnet1: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UNKNOWN qlen 500
>    link/ether fe:16:3e:16:b3:55 brd ff:ff:ff:ff:ff:ff
>    inet6 fe80::fc16:3eff:fe16:b355/64 scope link
>       valid_lft forever preferred_lft forever
> 
> # lsmod | grep _net
> vhost_net              30520  2
> macvtap                 9980  1 vhost_net
> tun                    17095  6 vhost_net
> 
> ("modprobe vhost_net" if you don't have it.)
> 
> # route -n
> Kernel IP routing table
> Destination   Gateway      Genmask         Flags Metric Ref  Use Iface
> X.X.X.X       0.0.0.0      255.255.255.128 U     0      0    0   br100
> 192.168.122.0 0.0.0.0      255.255.255.0   U     0      0    0   virbr0
> 169.254.0.0   0.0.0.0      255.255.0.0     U     1004   0    0   br100
> 0.0.0.0       X.X.X.X      0.0.0.0         UG    0      0    0   br100
> 
> You should have a route to your nova network in there (I use flat network so my nova net is X.X.X.X, same as my "real" subnet).
> 
> With all that in place try disabling iptables in the instance and pinging the host. On the host, run tcpdump on vnet0 and br100 to see if you get any traffic. I didn't initially, I think modprobe vhost_net was what fixed it. (I was poking at & restarting several things at once, so I'm not 100% sure exactly which of them did it.)
> 
> --
> Dimitri Maziuk
> Programmer/sysadmin
> BioMagResBank, UW-Madison -- http://www.bmrb.wisc.edu
> 
> 
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