On Wed, Aug 04, 2010 at 07:36:04PM +0300, Avi Kivity wrote:
This is basically my suggestion to libguestfs: instead of generating
an initrd, generate a bootable cdrom, and boot from that. The
result is faster and has a smaller memory footprint. Everyone wins.
We had some discussion of this upstream& decided to do this. It
should save the time it takes for the guest kernel to unpack the
initrd, so maybe another second off boot time, which could bring us
ever closer to the "golden" 5 second boot target.
It's not trivial mind you, and won't happen straightaway. Part of it
is that it requires reworking the appliance builder (a matter of just
coding really). The less trivial part is that we have to 'hide' the
CD device throughout the publically available interfaces. Then of
course, a lot of testing.
I will note that virt-install uses the -initrd interface for
installing guests (large initrds too). And I've talked with a
sysadmin who was using -kernel and -initrd for deploying VM hosting.
In his case he did it so he could centralize kernel distribution /
updates, and have the guests use /dev/vda == filesystem which made
provisioning easy [for him -- I would have used libguestfs ...].