[Users] Pxeboot

[Li, David]

Perry,

I am glad you brought this up.
I 'd be perfectly happy to run the root fs entirely in RAM. In fact that would be ideal for me. It's just I am not quite sure how to use pxeboot to achieve this. 

I am doing a test now using the tftpboot files created from the iso. 
As far as I see, the kernel boot options (pxelinux.cfg/default) has:

root=live:/ovirt-node-image-2.2.2-1.1.fc16.iso

With this I can only pxeboot to the intall screen.  What should I use to let the kernel mount the root fs in memory? Something like root=/dev/ram0?

David


>-----Original Message-----
>From: Perry Myers [mailto:pmyers at redhat.com]
>Sent: Wednesday, February 08, 2012 2:54 PM
>To: Mike Burns
>Cc: Li, David; users at ovirt.org
>Subject: Re: [Users] Pxeboot
>
>On 02/08/2012 05:03 PM, Mike Burns wrote:
>> On Wed, 2012-02-08 at 13:46 -0800, Li, David wrote:
>>> Mike,
>>>
>>> If I understand this correctly, today I should be able to pxeboot and
>>> nfs mount the root fs from a remote server.  Apart from setting up
>>> the pxe stuff, I 'd have to populate the ovirt node root fs on the
>>> server
>>> - perhaps steal it from a disk install.  In other words I am
>>> concerned about the point from which the kernel starts to execute
>>> /init script (in the initramfs) to the point /init is able to mount
>>> the final root fs from a remote server.
>>
>> No, there is no way to set this up currently in ovirt-node.  You could
>> install using a remote iscsi lun if you have a hardware iscsi HBA, but
>> there isn't a way to mount a remote nfs share as the root fs.
>>
>> Supporting a remote NFS share as the root fs isn't even something that
>> requested as an RFE at this point or on the roadmap as far as I'm
>> aware.
>>
>> It sounds like what you're really looking for is a shared root fs that
>> multiple hosts could use.  This is something that we will probably
>> look into eventually, but it's not on the immediate roadmap.
>
>Given that the rootfs of oVirt Node is fairly small and in a truly stateless
>environment would just run out of system RAM, there's no real reason to try
>to do a shared NFS based rootfs.  It's an unnecessary complication I think, if
>the end goal is to move to truly stateless.
>
>For larger systems where the rootfs is on the order of GB's, shared root may
>make more sense.