[openstack-dev] [nova] FreeBSD host support, round 2

Roman Bogorodskiy novel at FreeBSD.org
Tue Jun 9 16:52:39 UTC 2015


Few months ago I've started a discussion on FreeBSD host support for
OpenStack. [1] At a result of discussion it was figured out that there
are a number of limitations, mainly on the BHyVe (the FreeBSD hypervisor)
side, that make the effort not feasible.

However, some things changed since then. Specifically, FreeBSD's got Xen
dom0 support. [2] In context of OpenStack deployment that has a number of
benefits over bhyve. Specifically:

 * The stack is more mature and feature-rich
 * The toolstack is here already: libxl is available through the FreeBSD
   ports tree, libvirt/libxl works there with minimal modifications
   (already available in the git master)
 * OpenStack libvirt/libxl driver is already here

I was able to setup a proof-of-concept environment on FreeBSD that
required quite a small amount of modifications required in OpenStack:

 * Glance and Keystone didn't require any changes
 * Nove required some minor modifications mainly in the linux_net.py

The summary of Nova modifications:

 * I had to implement FreeBSD version of linux_net.LinuxNetInterfaceDriver.
   It currently doesn't support vlans though. 


   I keep it as an external package and configure Nova to use it through
   linuxnet_interface_driver config option in nova.conf
 * I had to create a stub for the IptablesManager class. I also had to
   add a config option to be able to override class for that in a way
   similar to interface driver.
 * I had to fix a minor interface incapability for NullL3 stub, that's
   already in the Nova tree: https://review.openstack.org/#/c/189001/
 * I added a hack to use 'phy' driver in domain's xml for disks because
   for some reason driver='qemu' results in guests not able to access
   disk devices (tried both FreeBSD and Linux guests). Need to
 * Dropped some LinuxBridgeInterfaceDriver hardcodes in

Here's a quick overview of my changes:


With this changes I was able to get things working, i.e. VM starting,
obtaining IP addresses (with nova-network configured with FlatDHCP) etc.

Having that said I'm wondering if community is interested in integrating
FreeBSD support through libvirt/libxl into mainline? Obviously, the
changes I provided are shortcuts and the appropriate specs should be
create with proposals of proper designs, not quick hacks like that.

The biggest part of the unportable code, just like it was in bhyve case,
is still linux_net.py, so probably it makes sense to revive the old


TBH, IMHO linux_net.py could have a refactor regardless of FreeBSD
support. It's approx. 2000 lines long, contains a lot of stuff like
dnsmasq handling code, interface handing code and firewall management
that could have their own place.

Feedback is appreciated,

1: http://lists.openstack.org/pipermail/openstack-dev/2014-October/048721.html
2: http://wiki.xen.org/wiki/FreeBSD_Dom0

Roman Bogorodskiy
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