[VMWare][Ubuntu][Devstack] external access to private network does not work

asked 2014-02-15 11:14:16 -0600

Nicolas gravatar image

updated 2014-02-15 14:36:01 -0600


After looking into lots of website, forums i haven't been able to find more information that could explain my challenge. I'm kind of a beginner with Devstack/openstack and start to become nuts with this network issue. Any helps / hints would be much appreciated.

I'm using VMWare workstation on my laptop to host a Ubuntu VM running devstack. So far everything works except external access to/from the private network: - My VMs deployed in devstack can speak to each other and ping the router (which is properly setup as a default gw) - My VMs deployed in devstack can not speak to anything in the Public network - Nothing in my public network can reach my VM deployed in devstack

from the devstack host ( is a devstack VM in the private network): nicolas@ubuntu-devstack:~/devstack$ ping

PING ( 56(84) bytes of data.
From icmp_seq=1 Destination Host Unreachable
From icmp_seq=2 Destination Host Unreachable
From icmp_seq=3 Destination Host Unreachable

from a VM to try to reach a server on the public network

I can't copy/paste it but when i try to ping sitting in the public network: from (my router interface on the private network) Destination Net unreachable

Some information on what i've done: On my ubuntu :

nicolas@ubuntu-devstack:~/devstack$ uname -a
Linux ubuntu-devstack 3.11.0-12-generic #19-Ubuntu SMP Wed Oct 9 16:20:46 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux

net.ipv4.conf.eth0.proxy_arp = 1
net.ipv4.ip_forward = 1
sudo iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

Here is my localrc file for devstack

nicolas@ubuntu-devstack:~/devstack$ cat localrc
disable_service n-net
enable_service q-svc
enable_service q-agt
enable_service q-dhcp
enable_service q-l3
enable_service q-meta
enable_service neutron
## Neutron . Neutron L4/L7 Network Service
#enable_service q-lbaas

# Optional, to enable tempest configuration as part of devstack
enable_service tempest

#the default pvs/lvs created by devstack is not big enough (pvs = 10Gb and it creates a 1G partition out of it)

#Enable logging in a file instead of having to use screen -r

./stack.sh run without issues and based on Horizon UI, all services are up and running.


nicolas@ubuntu-devstack:~/devstack$ ifconfig -a
br-ex     Link encap:Ethernet  HWaddr c6:73:30:31:3e:42
          inet addr:  Bcast:  Mask:
          UP BROADCAST RUNNING  MTU:1500  Metric:1
          RX packets:10 errors:0 dropped:0 overruns:0 frame:0
          TX packets:3 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX ...
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answered 2014-02-20 06:09:49 -0600

Nicolas gravatar image

Found the solution, it was a design issue ...


Here we should not specify the subnet that the Ubuntu VM has access to. we need to provide another subnet. By removing this line, devstack automatically use for the public network.

this give the following topology: Network <-> Ubuntu VM Eth0 <-> <->br-ex interface

and everything work

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Asked: 2014-02-15 11:14:16 -0600

Seen: 4,708 times

Last updated: Feb 20 '14