On Tue, 2011-03-15 at 14:46 -0400, Chris Lalancette wrote:
On 03/15/11 - 01:35:53PM, Ian Main wrote:
- We believe we can arrange to pass a small snippet of config data
in at launch time, to point a booting instance at some source of further config.
Kernel boot params, yes.
Note that this won't work. In general, you can't add kernel boot params to a guest, because we don't direct-boot the kernel. We boot the emulated BIOS, which calls grub, which calls the kernel.
Luckily there is a workaround. We can stuff some data into the SMBIOS tables during launch time, and use that as our injection mechanism instead.
There's also door #3, which would be hugely preferrable from an API POV: using kpartx^W libguestfs to directly inject files into the image. This is the approach Rackspace takes; IOW, we wouldn't introduce yet another paradigm of how to inject user data into an instance.
SMBIOS is fine for internal instrumentation (e.g., where to report IP address), but not for generic user data.
David