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Re: Help on Quantum installation through DevStack (openvswitch error) !!


Hi Hitesh,

> Setting up openvswitch-switch (1.2.0-1ubuntu3) ...
> FATAL: Module openvswitch_mod not found.
>  * Inserting openvswitch module
>  * not removing bridge module because bridges exist (br100 virbr0)

I interpret this as that the attempt to remove (Linux) "bridge" kernel
module was made, but it failed because there existed module
dependency, i.e. "br100" and "virbr0". Perhaps, "br100" and "virbr0"
were created using the Linux "bridge" kernel module rather than the
OpenVswitch (OVS) "brcompat_mod" kernel module.
Judging from the "FATAL" Module openvswitch_mod not found", my guess,
is that the system did not have OVS installed before invoking

Try removing br100 and virbr0 first and add them back once the OVS
installation is successfully done ?
You could use "brctl delbr"...

Note that I only use OVS for a few weeks, but this is my understanding...
OVS has its own bridge kernel module, "brcompat_mod" which could be
installed as part of OVS installation. To OVS users, "brcompat_mod"
kernel module performs what the default (Linux) "bridge" kernel module
does.  In order to install the "brcompat_mod" kernel module, the
default "bridge" module needs to be removed first. This implies that
any bridge created using the "bridge" kernel module, would need to be
deleted ("brctl delbr") before the "bridge" kernel module can be
removed. Once OVS is installed successfully, and both
"openvswitch_mod" and "brcompat_mod" are loaded into the kernel,  your
previously created bridges, br100 for example, can be recreated using
the "brcompat_mod" kernel module (transparently) via "ovs-vsctl" or
"brctl" shell commands.

Btw, I also found that the "brcompat_mod" does not automatically load
802.1q (VLAN) kernel module. Thus, if you plan to have a VLAN
interface on your bridge, you would have to load the "8021q" kernel
module manually after the "brcompat_mod" is loaded.

All of these kernel modules, "bridge", "openvswitch_mod",
"brcompat_mod" and "8021q" are dynamically loadable kernel modules
i.e. they can be loaded/unloaded at will using  "insmod" or

To install OVS manually, I use the "INSTALL.*" instruction files at
the top level directory in the OVS distribution tarball...
I also found both http://openvswitch.org/support/ - click the
hypervisor/scenario of choice, and the discussion archive at
http://openvswitch.org/pipermail/discuss/ helpful.


On Mon, Mar 12, 2012 at 3:17 PM, hitesh wadekar
<hitesh.wadekar@xxxxxxxxx> wrote:
> Hello Friends,
> I want to fix the "Quantum Starter Bugs"
> (http://wiki.openstack.org/QuantumStarterBugs) .  For this, I have enabled
> the quantum service in the DevStack script to install and run Quantum (
> added commands in ENABLE_SERVICE). However, while running the script I got
> these errors for Openvswitch (OVS).
> 0 upgraded, 0 newly installed, 0 to remove and 57 not upgraded.
> 1 not fully installed or removed.
> After this operation, 0 B of additional disk space will be used.
> Setting up openvswitch-switch (1.2.0-1ubuntu3) ...
> FATAL: Module openvswitch_mod not found.
>  * Inserting openvswitch module
>  * not removing bridge module because bridges exist (br100 virbr0)
> invoke-rc.d: initscript openvswitch-switch, action "start" failed.
> dpkg: error processing openvswitch-switch (--configure):
>  subprocess installed post-installation script returned error exit status 1
> No apport report written because MaxReports is reached already
>                                                               Errors were
> encountered while processing:
>  openvswitch-switch
> E: Sub-process /usr/bin/dpkg returned an error code (1)
> ++ failed
> ++ local r=100
> ++ set +o xtrace
> Also, I tried to install openvswitch manually, but had no luck !!.
> On the net I found that there is a bug for openvswitch (Ubuntu Oneiric)
> package ( https://bugs.launchpad.net/ubuntu/+source/openvswitch/+bug/894754
> )
> I am sure somebody would have already been come across this bug, any
> commands or steps that I need follow to install openvswitch on ubuntu
> oneric?
> Any input on this is highly appreciated.
> Thanks for your time.
> Thanks,
> Hitesh Wadekar
> hitesh.wadekar@xxxxxxxxx
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