Make 'no_timer_check' Kernel parameter for Fedora cloud images

[Kashyap Chamarthy]

On Wed, Jun 18, 2014 at 06:16:04PM +0100, Daniel P. Berrange wrote:
> On Wed, Jun 18, 2014 at 10:42:51PM +0530, Kashyap Chamarthy wrote:

[. . .]

> > Notes
> > -----
> > 
> >   - 'no_timer_check' parameter is added implicitly when the kernel
> >     detects it is booting under KVM.
> > 
> >     However when booting under QEMU TCG (software emulation) you have to
> >     add this to the guest kernel command line explicitly.
> 
> FYI, upstream OpenStack now explicitly adds this kernel parameter when
> possible, but it can only do this when booting from a kernel/initrd.
> If the guest is booting from a virtual BIOS, there's no option but
> to add it to the guest image grub.conf manually.

Yup, noticed this fix from LP bug -- 1312199. I see exactly your
point (it works only when you use '--append' w/ external
Kernel/initrd) echoed in comment #14[1], by rjones.

  [1] https://bugs.launchpad.net/cirros/+bug/1312199

> 
> commit 6b86a61fee15ce1237303fab2f7896f8c3bcad47
> Author: Attila Fazekas <afazekas at redhat.com>
> Date:   Wed May 28 09:19:29 2014 +0200
> 
>     Use no_timer_check with soft-qemu
>     
>     The Linux kernel timer check not working properly
>     when the hypervisor's thread preempted by the host CPU scheduler.
>     
>     The timer check is automatically disabled with other types
>     of hypervisors including the hardware accelerated kvm,
>     but timer_check is not disabled when qemu used without hardware acceleration.
>     
>     This issue is frequently mischaracterized as an SSH connectivity issue and
>     causes rechecks and occasional boot failures.
>     
>     This change adds no_timer_check kernel parameter when we are using
>     uec images with qemu.
>     
>     Closes-Bug: #1312199
>     Change-Id: I3cfdfe9048fe219fc12cdac8a399b496f237e55e
 

-- 
/kashyap