Monthly Archives: July 2013

OpenStack test event at Flock — Fedora Contributor’s conference (AUG 9-12)

Firstly, this post should have been coming from Matthias Runge, long time Fedora contributor, OpenStack Horizon developer. Earlier this May, Matthias proposed a FLOCK hack-fest session for OpenStack to test/fix latest packages on Fedora, and it was accepted. Matthias, unfortunately, cannot make it (Duh, he should have been there!) to Charleston due to personal reasons. He trusted I could handle the swap of places with him (I work with him as part of the Cloud Engineering team at Red Hat). Thanks Matthias!

Secondly, it’s not really flash news that FLOCK (Fedora Contributor’s conference), the first edition of the revamped (and now erstwhile) FUDCON, will be taking place in about two weeks (Aug 9-12) in Charleston, South Carolina.

If you care about Open Source Infrastructure as a Service software, and interested in contributing/learning/deploying, you’re more than welcome to participate (needless to say) in this session. There will also be a couple of core OpenStack developers hanging around during the conference!

Some practical information for the OpenStack test event:

  • Abstract: OpenStack FLOCK test event abstract is here.
  • Prerequisites: This is supposed to be a hands on session where we try to setup and test. Given the nature of OpenStack, if you can have a laptop with 4G (or more) memory, and (at-least) 50G of free disk space, it’ll make life easier while setting up OpenStack.
  • Current milestone packages: OpenStack Havana, milestone-2 packages are here.
  • Trunk Packages: These are built from OpenStack upstream trunk on an hourly basis. As of writing this, Neutron (OpenStack networking) server packages are not yet available (coming soon – people are working hard on this!). nova-network is the temporary recommendation. Further details are in the quickstart instructions
  • Bug tracking: If there are OpenStack Fedora/EL packaging, installation & related issues, file it in RH bugzilla. If you’re testing from upstream trunk, it’s better to file them under upstream issue tracker
  • An etherpad instance with more verbose information here. If you have comments/suggestions/notes, please add it there.

Finally, there are plenty of interesting sessions – check out the schedule!

PS: Damn it, Seth Vidal — I was dearly looking forward for your user builds tools talk :( Just noticed Kyle McMartin is doing it on Seth’s behalf.



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Configuring Libvirt guests with an Open vSwitch bridge

In the context of OpenStack networking, I was trying to explore Open vSwitch. I felt it’s better to go one step back, and try with a pure libvirt guest before I try it with OpenStack networking.

On why Open vSwitch compared to regular Linux bridge?

  • In short (as Thomas Graf, Kernel networking subsystem developer, put it) — Software Defined Networking(SDN)
  • Open vSwitch’s upstream documentation provides a more detailed explanation.

Here’s a simple scenario, where the machine in test has a single physical NIC, obtaining its IP address from DHCP. And, running KVM guests managed via libvirt.

Install Open vSwitch

Install the Open vSwitch package (this is on Fedora 19):

$ yum install openvswitch -y

Enable the openvswitch systemd unit file, and start the daemon:

$ systemctl enable openvswitch.service
$ systemctl start openvswitch.service

Check the status Open vSwitch service, to ensure it’s ‘Active’:

$ systemctl status openvswitch.service

Configure Open vSwitch (OVS) bridge
Before you proceed, ensure to have physical access or access via serial console to the machine, because, associating a physical interface with an Open vSwitch bridge will result in lost connectivity.
Reasoning is here under the ‘Configuration problems’ section.

Add an OVS bridge device:

$ ovs-vsctl add-br ovsbr0

Associate the OVS bridge device to eth0 (or em1). (At this point, network connectivity will be lost.)

$ ovs-vsctl add-port ovsbr0 eth0

I was obtaining IP address to my host from DHCP, so I first cleared it from the physical interface, and associated it with the Open vSwitch bridge device (ovsbr0).

$ ifconfig eth0
$ ifconfig ovsbr0 10.xx.yyy.zzz

I killed the existing dhclient instance on ‘eth0’, and initiated it on ovsbr0:

$ dhclient ovsbr0 &

List the OVS database contents

$ ovs-vsctl show
        Bridge "ovsbr0"
            Port "eth0"
                Interface "eth0"
            Port "ovsbr0"
                Interface "ovsbr0"
                    type: internal
        ovs_version: "1.10.0"

Update libvirt guest’s bridge source

I have an existing KVM guest, managed by libvirt, with its default network source associated with libvirt’s ‘virbr0). Let’s modify its network to Open vSwitch bridge.

Edit the libvirt’s guest XML

$ virsh edit f18vm

The attribute should look as below (take note of the highlighted attributes):

    <interface type='bridge'>
      <mac address='52:54:00:fb:00:01'/>
      <source bridge='ovsbr0'/>
      <virtualport type='openvswitch'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>

Once the guest XML is edited and saved, dump its contents to stdout, you’ll notice an additional attribute interfaceid added automatically:

    $ virsh dumpxml f18vm | grep bridge -A8
       <interface type='bridge'>
         <mac address='52:54:00:fb:00:01'/>
         <source bridge='ovsbr0'/>
         <virtualport type='openvswitch'>
           <parameters interfaceid='74b6858e-8012-4caa-85c7-b64902a19605'/>
         <model type='virtio'/>
         <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
       <serial type='pty'>
         <target port='0'/>

Start the guest, and check if it’s IP address matches the host subnet:

$ virsh start fed18vm --console
$ ifconfig eth0


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Unattended F19 guest creation with Oz

Oz has been in development for a couple of years, which lets you install various guest operating systems with minimal user-input.

A simple wrapper script is here

$ yum install oz -y
$  ./oz-jeos.bash guest-name distro
      'distro': f19, f18
       Examples: oz-jeos.bash f19-jeos f19  # create f19
                 oz-jeos.bash f18-jeos f18  # create f18

If you prefer to invoke manually…

Create a TDL (Template Description Language) file:

$ cat << EOF > f19.tdl
    <install type='url'>
  <description>Fedora 19</description>

NOTE: From the above TDL file, you can elide the disk attribute if you don’t need 25G of disk. The default disk size is 10G.

Invoke Oz:

$ oz-install -d 4 f19.tdl 2>&1 \
  | tee /var/tmp/f19-oz-log.txt


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