[Fedora-livecd-list] Live ISO within initrd for PXE Boot?

[Douglas McClendon]

Warren Togami wrote:
> http://git.fedoraproject.org/git/?p=livecd;a=commit;h=e0f0269d3a8f8f310e7c5fdfb8af45892f419c13 
> 
>>
>> The way it works is to bundle the complete ISO image inside the initrd.
>> The kernel and (bloated) initrd are downloaded using PXE in the normal
>> way, and the init script finds and loopback-mounts the ISO image and
>> booting continues as normal.
> 
> Wow.  I don't mean to offend, but this seems like an incredibly bad way 
> of doing this.  Isn't this really slow in the boot up because you must 
> wait for the entire ISO to download?  It also requires the client to 
> have more than enough RAM to have the entire ISO in memory?  It sounds 
> like the entire memory used by the ISO remains unavailable to the booted 
> system.
> 
> I need something similar to boot read-only OS images over PXE boot for 
> LTSP.  Upstream LTSP5 uses nbd to serve a raw squashfs image as a 
> network block device, which means only a tiny bit needs to be in the 
> initrd and very little memory overhead.  Parts of the read-only image 
> are streamed over the network on demand.


One architecture I've outlined here in the past, but haven't gotten 
around to implementing yet is-

mount the squashfs via nfs or fuse-httpfs or the like, then otherwise do 
everything else the same.  Then post-boot, allow the user if they wish 
to migrate the used squashfs either to ram or local disk via the same 
devicemapper mirror 'trick' I used for rebootless installation.

Then subsequently (or alternately) you can use my rebootless 
installation technique to convert the LiveOS(network-style) type running 
OS into a completely normal installed running OS, without even having to 
reboot.  bwahahaha...

I forget the persons name, but I remember someone had already done the 
first part of that, who posted here and on anaconda-devel within the 
last year.


-dmc

> I'm waiting on Jeremy to get back regarding a long-term plan for 
> supporting mayflower-like things within mkinitrd itself.  NBD support 
> was not accepted into mkinitrd because it would rely upon mayflower-like 
> functionality to do right.
> 
> Warren Togami
> wtogami at redhat.com
> 
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