Hello all,
I have a need for managing "local clouds" and I was hoping to add
support to libcloud for such a thing, since I'm already using it for
remote/private cloud management. When I brought this up in IRC, someone
mentioned the idea of creating a libvirt (http://libvirt.org/) driver for
libcloud. That being said, I've created a GitHub fork for that purpose
(https://github.com/jcscoobyrs/libcloud). I have committed only one revision
at this time but it does add partial libvirt support such that you can connect
to any of the supported libvirt hypervisors, although I've only tested
VirtualBox, and list nodes with node information. As the effort stands right
now, once you successfully create a LibvirtNodeDriver (LND), you can perform
the following:
* LND.list_nodes()
* LND.destroy_node(Node)
* LND.reboot_node(Node)
For an example in action:
>>> from libcloud.compute.drivers import virtlib
>>> d = virtlib.LibvirtNodeDriver('vbox')
>>> d.list_nodes()
[<Node: uuid=c11d579a204f0c41102bd2fde52ea4364856ff30, name=Ubuntu, state=2,
public_ip=None, provider=Libvirt Node Provider (VirtualBox) ...>, <Node:
uuid=a79ecb055026d19949dee544e532e5ca87a8f75c, name=Fedora, state=2,
public_ip=None,
provider=Libvirt Node Provider (VirtualBox) ...>]
>>> nodes = d.list_nodes()
>>> nodes[0].extra
{'os_type': 'hvm', 'ram': 1024L, 'cpus': 1, 'snapshot_names': ['Initial Working
State']}
>>> nodes[0].name
'Ubuntu'
>>> nodes[0].id
'387ea2e2-997c-46a0-9d07-e183d6a1dda1'
So given the list of functions implemented above, there are a few others that
need implementing to finish libvirt's initial support:
* LND.create_node()
* LND.deploy_node() (I'm not sure this one is something that I plan on doing
initially.)
* Constants for making the API easier to use and more intuitive
* Helper functions for getting Libvirt/driver information
* Helper functions for easing the interaction with libvirt
That being said, when I started working on the create_node function, I ran into
a problem where function signatures that libcloud publishes/expects no longer
make sense in the libvirt world. In libvirt, there is no notion of images,
locations and sizes. In libvirt, you create an XML document and that is what
describes the new guest/node and its "pieces" (http://libvirt.org/format.html).
(I do have an idea about locations where it could list the currently available
hypervisors that libvirt was compiled with support for but the other things do
not really lend themselves to be done.)
The purpose of this email is really two fold:
1) Show my current work so others can critique/test
2) Explain the problems I'm facing with finishing this up
All of this being said, let's talk about the feasibility of libvirt support
being in libcloud and if it's feasible, how might I be able to get past the
initial problem of describing guests/nodes in a way that libvirt needs without
completely diverting from the libcloud API.
Take care,
Jeremy Whitlock <[email protected]>
Twitter: jcscoobyrs
Website: http://www.thoughtspark.org
