how to pass kernel parameters to VMs

[Steve Roth <st...@oracle.com>]

Hi all,

Is there any way when starting a VM to override/pass kernel parameters, 
such as single?  (for single-user mode)

I guess this presumes Linux VMs.

We're looking for a way to pass a 'purpose' to a VM (other than its 
name).   One way would appear to be the 'userdata' field in the 
deployVirtualMachine API  (presuming there is a way to fetch this value 
once the VM boots up).     I'm just wondering if we could use a kernel 
parameter as well.

If it's helpful, we are using KVM as our hypervisor.

Thanks!
-Steve

Re: how to pass kernel parameters to VMs

[Steve Roth <st...@oracle.com>]

Great ideas -- thanks Shanker!

-Steve

On 09/04/2013 03:09 AM, Shanker Balan wrote:
> On 04-Sep-2013, at 2:45 AM, Steve Roth <st...@oracle.com> wrote:
>
>> Hi all,
>>
>> Is there any way when starting a VM to override/pass kernel parameters, such as single?  (for single-user mode)
> Here is how I do it:
>
> 1) Open a console session to the VM
> 2) Reboot
> 3) Wait for boot loader prompt
> 4) Modify kernel boot options as applicable
> 5) Boot kernel
>
>
>> I guess this presumes Linux VMs.
>>
>> We're looking for a way to pass a 'purpose' to a VM (other than its name).   One way would appear to be the 'userdata' field in the deployVirtualMachine API  (presuming there is a way to fetch this value once the VM boots up).     I'm just wondering if we could use a kernel parameter as well.
>>
>> If it's helpful, we are using KVM as our hypervisor.
>
> This is a little trick I did at previous $work:
>
> 1) All hosts are set to PXE boot first and then local HDD
> 2) For any host that needed a "rescue", PXE boot settings were put in place with the correct hex id
> 3) Reboot host
> 4) Host picks up the netboot kernel with the special boot options and the correct root disk
> 5) Host lands into rescue mode
> 6) Rescue the OS using the console
> 7) Remove the PXE boot config
> 8) Reboot host, host boots as usual
>
> Hth.
>
> --
> @shankerbalan
>
> M: +91 98860 60539 | O: +91 (80) 67935867
> shanker.balan@shapeblue.com | www.shapeblue.com | Twitter:@shapeblue
> ShapeBlue Services India LLP, 22nd floor, Unit 2201A, World Trade Centre, Bangalore - 560 055
>
> This email and any attachments to it may be confidential and are intended solely for the use of the individual to whom it is addressed. Any views or opinions expressed are solely those of the author and do not necessarily represent those of Shape Blue Ltd or related companies. If you are not the intended recipient of this email, you must neither take any action based upon its contents, nor copy or show it to anyone. Please contact the sender if you believe you have received this email in error. Shape Blue Ltd is a company incorporated in England & Wales. ShapeBlue Services India LLP is operated under license from Shape Blue Ltd. ShapeBlue is a registered trademark.

Re: how to pass kernel parameters to VMs

[Shanker Balan <sh...@shapeblue.com>]

On 04-Sep-2013, at 2:45 AM, Steve Roth <st...@oracle.com> wrote:

> Hi all,
>
> Is there any way when starting a VM to override/pass kernel parameters, such as single?  (for single-user mode)

Here is how I do it:

1) Open a console session to the VM
2) Reboot
3) Wait for boot loader prompt
4) Modify kernel boot options as applicable
5) Boot kernel


>
> I guess this presumes Linux VMs.
>
> We're looking for a way to pass a 'purpose' to a VM (other than its name).   One way would appear to be the 'userdata' field in the deployVirtualMachine API  (presuming there is a way to fetch this value once the VM boots up).     I'm just wondering if we could use a kernel parameter as well.
>
> If it's helpful, we are using KVM as our hypervisor.


This is a little trick I did at previous $work:

1) All hosts are set to PXE boot first and then local HDD
2) For any host that needed a "rescue", PXE boot settings were put in place with the correct hex id
3) Reboot host
4) Host picks up the netboot kernel with the special boot options and the correct root disk
5) Host lands into rescue mode
6) Rescue the OS using the console
7) Remove the PXE boot config
8) Reboot host, host boots as usual

Hth.

--
@shankerbalan

M: +91 98860 60539 | O: +91 (80) 67935867
shanker.balan@shapeblue.com | www.shapeblue.com | Twitter:@shapeblue
ShapeBlue Services India LLP, 22nd floor, Unit 2201A, World Trade Centre, Bangalore - 560 055

This email and any attachments to it may be confidential and are intended solely for the use of the individual to whom it is addressed. Any views or opinions expressed are solely those of the author and do not necessarily represent those of Shape Blue Ltd or related companies. If you are not the intended recipient of this email, you must neither take any action based upon its contents, nor copy or show it to anyone. Please contact the sender if you believe you have received this email in error. Shape Blue Ltd is a company incorporated in England & Wales. ShapeBlue Services India LLP is operated under license from Shape Blue Ltd. ShapeBlue is a registered trademark.