On Mon, Jun 16, 2014 at 11:54 AM, Karanbir Singh mail-lists@karan.org wrote:
On 06/10/2014 05:21 PM, Lars Kurth wrote:
== #4 Cloud Image from Cloud Image SIG == We could rely on pre-built cloud images from the Cloud Images SIG. People could just download the cloud image once it's done and customize it, rather than installing / building their own.
Advantages: seems easy
Disadvantages: coordination with Cloud Images SIG. May not be flexible enough
We ship a test/devel grade CentOS-6-x86_64-pv image ( well, its a qcow2 image, should work for pvhvm as well, the fstab is label driven ).[1]
The biggest problem in doing pre-baked images is the instance metadata. We need to find an easy way to get network settings into the instance and the root password ( or key ), and finally - in some cases, console redirection/setup, but i dont think the console is a deal breaker or a big deal. The network and access credentials however are.
In a typical cloud environ this info would come from the cloud controller's metadata service; on a typical virtualised setup though this becomes an issue ( and isnt really Xen specific ).
A couple of notes on virt-builder:
* When I tried it, all of the images booted on Xen out-of-the-box except Fedora 19 and 20; I reported this to the list and the developers were very responsive, so now everything works. (The exception might be RHEL7-rc, but I think should be gone now.) * However, libguestfs has a massive dependency tree in RHEL7 for some reason; KB said that a "yum install libguestfs" wanted to install 178 additional RPMs. A minimal C6 install is only 143 RPMs, so this more than doubles it. That makes this a bit less desirable as the primary method of getting a system up and running quickly.
So it looks like we might want to recommend three potential paths we could recommend people to explore:
1) For basic CentOS VMs, use a CentOS-provided cloud image, with our custom metadata tweaking script.
2) For more versatile image set-up and manipulation (including other operating systems), use virt-builder.
3) If you're thinking about using libvirt anyway, use virt-install and install from installation media.
Does that sound reasonable?
#1 still has some issues we need to work out -- particularly with sorting out the metadata. I'll start a separate thread to talk about that.
-George