[ovs-discuss] Assistance with setting-up Open vSwitch

Justin Pettit jpettit at nicira.com
Mon Dec 21 23:13:52 UTC 2009

On Dec 21, 2009, at 2:31 PM, Ali Sydney wrote:

> ERROR 1.
> checking for SSL... no
> configure: WARNING: Cannot find libssl:
>   No package 'libssl' found
>   OpenFlow connections over SSL will not be supported.
> ERROR 2.
> checking for /lib/modules/ directory... no
> configure: error: source dir /lib/modules/ doesn't exist
> Now I know that OpenSSL (The package which contains libssl) is installed (because I have checked on the installed version "OpenSSL 0.9.8g 19 Oct 2007"). Can you please provide some idea as to why I would be encountering this problem? Also, is it a MUST to install a "kernel" based switch to obtain MAXIMUM switch performance? 

My guess is that you don't have the OpenSSL development package installed (this contains headers and libraries that we need to link against).  I don't use Fedora, but a quick search indicates that the package is called "openssl-devel".  This may be the one you want:


On the kernel issue, my guess is that you don't have the kernel headers installed.  I think this is the package you likely want:


For maximum performance, you do need the kernel-based switch.  If you run it from userspace, then every packet has to make the kernel/userspace transition. 

> 4. To bypass these 2 errors, I simply run "./configure," then "make," and "make install." Everything seems to have worked fine.

Right, this bypasses building the kernel module and SSL support...

> 5. Now, I have setup a simple configuration file with a bridge named "lucia" which has three external ports.
> bridge.lucia.port=eth0
> bridge.lucia.port=eth1
> bridge.lucia.port=eth2

If you're not going to use the kernel module, you need to use a slightly different configuration.  It's described below:


Note that you need to be working from the master branch in order to have userspace support.  The tarballs we've been putting up on the site are from the "citrix" branch.  You can get a snapshot of the master branch by clicking here:


> 6. Below is the 4 final lines in the output of the command "#ovs-vswitchd":
> Dec 21 16:14:46|00514|dpif|WARN|/dev/net/dp255: open failed (No such device or address)
> Dec 21 16:14:46|00515|bridge|ERR|failed to delete datapath dp255: No such device or address
> Dec 21 16:14:46|00516|dpif|WARN|/dev/net/dp0: open failed (No such device or address)
> Dec 21 16:14:46|00517|bridge|ERR|failed to create datapath lucia: No such device or address
> How do I define the device/bridge "lucia" and its 3 external ports (eth0, eth1, eth2)? 

If you follow those userspace instructions (or build the kernel module), you shouldn't see these errors.


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