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openstack single node single nic

asked 2013-06-13 05:33:01 -0600

polslinux gravatar image

updated 2013-06-13 05:33:36 -0600

I would like to install OpenStack 2013.1.1 on Ubuntu 13.04 which is installed in my notebook.
I thought to follow this guide: but i have some doubts:

  1. I have only 1 NIC so what i have to do? Just ignore where the guide say "add eth0"?
  2. I want that all the VMs can be connected to my LAN ( so with 1 NIC is this possible?


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answered 2013-06-13 07:48:46 -0600

Vic gravatar image

updated 2013-06-13 07:50:03 -0600

yes, it is possible. configure all the endpoints with the same IP address from the only interface, which mostly will be eth0. And turn on promisc mode for the NIC.

Have to mentioned that I haven't done it on newer version of Ubuntu yet, tried on 10.04 and centos6.3.

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What guide have you follow? Because i always stuck when i try to ping or ssh into the VM :( i cannot manage to get the VM take the floating ip -.-''

polslinux gravatar imagepolslinux ( 2013-06-14 06:47:05 -0600 )edit

have i to setup a bridge or something like this? or just eth0 is needed??

polslinux gravatar imagepolslinux ( 2013-06-14 07:08:51 -0600 )edit

three bridges should be added: br-external, br-internal and br-tun. br-tun will connect the VMs, it provides connectivity. br-internal provide NAT/route to other nodes. external is the gateway. you can ssh to it by using, sudo ip netns exec $NETNS_ID ssh cirros@

Vic gravatar imageVic ( 2013-06-21 03:07:19 -0600 )edit

if you want to give external connectivity, e.g ping your VM from any node. The route has to be added to routing table, and external connectivity should be working well. I am stuck at this step. sometimes the external ping works, sometimes not.

Vic gravatar imageVic ( 2013-06-21 03:10:18 -0600 )edit

I used several different guides, they are all right on certain parts and conflict on others, have to pick parts.

Vic gravatar imageVic ( 2013-06-21 03:10:40 -0600 )edit

answered 2014-01-23 08:37:08 -0600

MarcoC gravatar image

updated 2014-01-23 08:53:01 -0600


assuming that you are installing Ubuntu on your bare metal PC, the first thing to do is to configure the only one NIC you have as needed. Note that the NIC will be used for accessing the Operating System (ubuntu), the services (API endpoints), the dashboard (Horizon) and for "exposing" VMs when you associate a floating IP address to them.

Let's make some assumptions for proceeding with the explanation:

1) you want to install Havana with Neutron (not nova-network) 2) your installation is really a single node; i.e. you are not going to add compute nodes in the future

The first thing to do is to configure the network at Operating System level.

You need an OpenVSwitch bridge for several purposes so create that with command:

sudo ovs-vsctl add-br br-ex

Then you need to configure the network at OS level.

The following is an example of how you can configure the network using /etc/network/interfaces:

auto lo iface lo inet loopback

auto eth1 iface eth1 inet manual up ip address add 0/0 dev $IFACE up ip link set $IFACE up up ifconfig $IFACE promisc up ifconfig $IFACE multicast down ip link set $IFACE down

auto br-ex iface br-ex inet static address <static-ip-address> netmask <mask> network <network> broadcast <broadcast> gateway <gateway-ip-address> up ifconfig $IFACE promisc dns-nameservers <dns-ip-address> The first entry configures the loopback interface: no explanation is needed.

The second entry "starts" the interface whenever you switch on the PC. It's worth noticing that you do not assign any IP address to such an interface and this is needed because this interface will 'capture' all the traffic on the physical network it is connected to. The 'captured' traffic will be forwarded to all the virtual devices connected to the interfaces and one of such devices is br-ex.

The third entry configures br-ex, an OpenVSwitch bridge that will serve for the following purposes:

  • give access to the services (API endpoints) and Horizon
  • give access to the PC's Operating System (ubuntu)
  • give access to VMs in the cloud when they are associated to a floating IP address

After preparing the file in this way, you reboot the PC. It is fundamental to access the PC after the reboot from the console because if you try to access from ethernet you fail. The reason being that you have a single NIC but it is not assigned any IP address.

After accessing through the local console, you should see that you have three interfaces (ifconfig command):

lo Link encap:Local Loopback inet addr: Mask: inet6 addr: ::1/128 Scope:Host UP LOOPBACK RUNNING MTU:65536 Metric:1 RX packets:91931 errors:0 dropped:0 overruns:0 frame:0 TX packets:91931 errors:0 dropped:0 overruns:0 carrier:0 collisions:0 txqueuelen:0 RX bytes:19815734 (19.8 MB) TX bytes:19815734 (19.8 MB)

eth1 Link encap:Ethernet HWaddr 00:1a:4b:dd:44:5e inet6 addr: fe80::21a ... (more)

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answered 2013-07-02 16:03:16 -0600

comiq gravatar image

Yes, I have the same problem. I found on various forums and websites, that using virtual NIC is enough to solve the problem. E.g.: "If you have one NIC you can use a vNIC i.e. eth0 & eth0:1" "so in your above setup instead of eth2 you can replace it with eth0.22(just an example) and proceed." So is it really a solution?

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yes, i'm using vNIC now :)

polslinux gravatar imagepolslinux ( 2013-07-08 07:54:25 -0600 )edit

I'm digging around trying to find a reference for Linux VNIC's and all I'm finding are links to Oracle documentation or Can anyone confirm that Ubuntu 13.04 does indeed have a VNIC feature and point me to the docs? Thx!

Nathan gravatar imageNathan ( 2013-09-01 11:51:31 -0600 )edit

answered 2015-08-04 19:55:48 -0600

ubchaudhry gravatar image

Installing Ubuntu OpenStack requires at least seven machines with two disks, two of which have two network interfaces (NICs). Install Ubuntu Server on one of the machines with two interfaces.

Why do I need two disks? What if I have 7 machines with 2TB capacity each but on a single disk? Would this setup not work i:e ( Why do we need 2 interfaces on two machines? I understand for one machine, one interface connects to the internet and the second to the local network. But why do we need 2 interfaces for the second machine?

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Asked: 2013-06-13 05:33:01 -0600

Seen: 4,804 times

Last updated: Aug 04 '15