(2015-09-16 17:47)allenb Wrote:  This seems identical to the bug described here https://bugs.centos.org/print_bug_page.php?bug_id=8295 but switching to one of the fixed kernels makes no difference.

(2015-09-16 19:35)mcb30 Wrote:  Could you post the first few lines of the kernel output (including the kernel version and the command line)?

(2015-09-16 19:48)allenb Wrote:  Sure, here's the last one I've got handy. It's with the most current CentOS kernel but that doesn't appear to have changed the failure any. It should match up with the other lines I posted earlier:

[ 0.000000] Linux version 3.10.0-229.14.1.el7.x86_64 (builder@kbuilder.dev.centos.org) (gcc version 4.8.3 20140911 (Red Hat 4.8.3-9) (GCC) ) #1 SMP Tue Sep 15 15:05:51 UTC 2015

(2015-09-16 20:21)mcb30 Wrote:  That log shows a RHEL7 kernel, but you are talking about the "latest CentOS kernel".

The relevant kernel fix was in 3.16.0. You are using a 3.10.0 kernel to which the fix may or may not have been backported. I really do need to know exactly which kernel version you are using.

(2015-09-16 20:33)allenb Wrote:  

(2015-09-16 20:21)mcb30 Wrote:  That log shows a RHEL7 kernel, but you are talking about the "latest CentOS kernel".

The relevant kernel fix was in 3.16.0. You are using a 3.10.0 kernel to which the fix may or may not have been backported. I really do need to know exactly which kernel version you are using.

Hi Michael,

Kernel is definitely CentOS. It's from here:

http://mirror.centos.org/centos/7/centosplus/x86_64/Packages/kernel-plus-3.10.0-229.14.1.el7.centos.plus.x86_64.rpm

Per the reference in https://bugs.centos.org/view.php?id=8295, this should contain the backported patch. In my experience, it fails identically to the stock CentOS pxelinux image at http://mirror.centos.org/centos/7/os/x86_64/images/pxeboot/vmlinuz.

As best I can determine, either I'm hitting a different (but similar) bug, or the fix isn't really in that centosplus kernel.

Thanks,
Allen

(2015-12-17 13:09)fbacchella Wrote:  Any news about that ? Just tried on Centos 7.2, no change.

(2016-02-01 21:49)allenb Wrote:  

(2015-12-17 13:09)fbacchella Wrote:  Any news about that ? Just tried on Centos 7.2, no change.

Hi All,

I worked around it at the time, because CentOS 7 wasn't critical to me yet. But I'm back there now. Am building latest (as of today) iPXE from source, including 64 bit ipxe.efi module.

On an HP G8 box (BIOS), I'm able to boot as expected, using the "vmlinuz" and "initrd.img" files provided at http://mirrors.greenmountainaccess.net/centos/7.2.1511/os/x86_64/images/pxeboot/vmlinuz (just an example).

On an HP G9 box (UEFI), the kernel boots but ultimately comes crashing down in the usual manner:

No filesystem could mount root, tried:
Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)

Am going to swap in a different kernel and drivers to see if that makes any difference, will report back.

(2016-02-02 01:27)MultimediaMan Wrote:  The message you are seeing occurs because the vmlinuz cannot find the initrd.

In a UEFI system, the EFI_STUB in the Kernel needs initrd to specified as a path. PCBIOS can "figure it out". Typically, "initrd=initrd.img" is enough. If you have multiple initrd files you may need to specify them as "initrd=initrd.img,drivers.ko" or "initrd=initrd.img initrd=drivers.ko"

Example:

Code:

#!ipxe
echo EFI or PCBIOS
initrd ${17}/Media-Depot/linux/CentOS/latest/EL/x86-64/OEM/os/images/pxeboot/initrd.img
chain ${17}/Media-Depot/linux/CentOS/latest/EL/x86-64/OEM/os/images/pxeboot/vmlinuz initrd=initrd.img

(2016-02-02 01:27)MultimediaMan Wrote:  The message you are seeing occurs because the vmlinuz cannot find the initrd.

In a UEFI system, the EFI_STUB in the Kernel needs initrd to specified as a path. PCBIOS can "figure it out". Typically, "initrd=initrd.img" is enough. If you have multiple initrd files you may need to specify them as "initrd=initrd.img,drivers.ko" or "initrd=initrd.img initrd=drivers.ko"

Example:

Code:

#!ipxe
echo EFI or PCBIOS
initrd ${17}/Media-Depot/linux/CentOS/latest/EL/x86-64/OEM/os/images/pxeboot/initrd.img
chain ${17}/Media-Depot/linux/CentOS/latest/EL/x86-64/OEM/os/images/pxeboot/vmlinuz initrd=initrd.img

(2016-02-02 17:25)allenb Wrote:  What I was doing:

kernel blahblah initrd=foobar.img
initrd foobar.img
boot

What actually works with the "out of the box" pxeboot files:

initrd foobar.img
chain blahblah initrd=foobar.img

(2016-02-03 11:26)mcb30 Wrote:  Those are identical as far as iPXE is concerned: the only difference is in which file gets downloaded first. This will affect the placement in memory, which could potentially make a difference if your kernel does not include the backported fix mentioned earlier.

Michael

(2016-02-18 16:54)karakTaka Wrote:  Hi,

I managed to get centos booting by adding the squash image directly to my ipxe config.
Seems like in BIOS mode this file can be retrieved autimatically by the system, but not in UEFI mode.

This squashfs image is located here by example: http://mirror.centos.org/centos-7/7/os/x86_64/LiveOS/

:centos-install-7
echo Starting CentOS 7 ${archl} installer
set base-url ${boot-url}/unattended/centos
kernel ${base-url}/centos7_${archl}.kernel initrd=centos7_${archl}.initrd inst.repo=http://${128.1:string}/centos/7/os/x86_64
initrd ${base-url}/centos7_${archl}.initrd
initrd ${base-url}/centos7_${archl}.squash
boot || goto failed
goto start

(2016-02-02 17:25)allenb Wrote:  Hi MM,

Have been using "initrd=" in all of my UEFI testing. Still finding that things work when I replace the kernel & drivers with ones from ELRepo and do not work when using the standard releases from CentOS 7. Would be curious if this workaround does the trick for anyone else.

This is on HP G9 hardware, DL380 specifically, in UEFI mode.

Was unaware that multiple initrd files could be used. That's handy, thanks!

Allen

(2016-02-02 01:27)MultimediaMan Wrote:  The message you are seeing occurs because the vmlinuz cannot find the initrd.

In a UEFI system, the EFI_STUB in the Kernel needs initrd to specified as a path. PCBIOS can "figure it out". Typically, "initrd=initrd.img" is enough. If you have multiple initrd files you may need to specify them as "initrd=initrd.img,drivers.ko" or "initrd=initrd.img initrd=drivers.ko"

Example:

Code:

#!ipxe
echo EFI or PCBIOS
initrd ${17}/Media-Depot/linux/CentOS/latest/EL/x86-64/OEM/os/images/pxeboot/initrd.img
chain ${17}/Media-Depot/linux/CentOS/latest/EL/x86-64/OEM/os/images/pxeboot/vmlinuz initrd=initrd.img

---

Ah, unbelievable!

There was an important bit of detail in MM's response that I almost missed. It turns out the method that I was using in our config files wasn't quite right. I'd inherited it from previous efforts and because it worked in many cases, including UEFI with an alternate kernel, it seemed correct.

What I was doing:

kernel blahblah initrd=foobar.img
initrd foobar.img
boot

What actually works with the "out of the box" pxeboot files:

initrd foobar.img
chain blahblah initrd=foobar.img

Better to know now than never. Hope this helps some others. Thanks, MM.

Cheers,
Allen

(2016-02-02 01:27)MultimediaMan Wrote:  The message you are seeing occurs because the vmlinuz cannot find the initrd.

In a UEFI system, the EFI_STUB in the Kernel needs initrd to specified as a path. PCBIOS can "figure it out". Typically, "initrd=initrd.img" is enough. If you have multiple initrd files you may need to specify them as "initrd=initrd.img,drivers.ko" or "initrd=initrd.img initrd=drivers.ko"

Example:

Code:

#!ipxe
echo EFI or PCBIOS
initrd ${17}/Media-Depot/linux/CentOS/latest/EL/x86-64/OEM/os/images/pxeboot/initrd.img
chain ${17}/Media-Depot/linux/CentOS/latest/EL/x86-64/OEM/os/images/pxeboot/vmlinuz initrd=initrd.img

(2016-02-18 16:54)karakTaka Wrote:  Hi,

I managed to get centos booting by adding the squash image directly to my ipxe config.
Seems like in BIOS mode this file can be retrieved autimatically by the system, but not in UEFI mode.

This squashfs image is located here by example: http://mirror.centos.org/centos-7/7/os/x86_64/LiveOS/

:centos-install-7
echo Starting CentOS 7 ${archl} installer
set base-url ${boot-url}/unattended/centos
kernel ${base-url}/centos7_${archl}.kernel initrd=centos7_${archl}.initrd inst.repo=http://${128.1:string}/centos/7/os/x86_64
initrd ${base-url}/centos7_${archl}.initrd
initrd ${base-url}/centos7_${archl}.squash
boot || goto failed
goto start