> On 30.08.2021, at 23:26, Brian C. Lane <bcl@xxxxxxxxxx> wrote:
>
> On Thu, Aug 26, 2021 at 06:11:49PM +0200, Markus Falb wrote:
>
>> The solution is to activate the LVs in %pre
>> It turns out that there is /dev/sda present but not the device files for /dev/sdaX.
>>
>> …snip
>> %pre
>> mknod /dev/sda2 b 8 2
>> pvscan
>> vgchange -ay
>> %end
>> snap…
>>
>> alternatively this oneliner is working too, interestingly
>>
>> …snip
>> %pre
>> parted /dev/sda unit MiB print
>> %end
>> snip…
>>
>> Note that with the parted command it is not necessary to vgchange afterwards.
>>
>> Is there a builtin kickstart command that accomplishes the same instead of some %pre?
>> If not, why is %pre necessary? %pre was not necessary with RHEL7. Is this by design or is it a bug?
>
> This is a bug of some sort, as David said. The fact that parted print
> fixed it makes me think that your storage is slow, since all parted does
> is open/close the device and tell the kernel to rescan the partitions --
> which should have already happened at boot time when the device
> appeared.
I am testing with a kvm VM created with Virtual Machine Manager on CentOS 7.
The VM has a scsi disk (changing to IDE or SATA does not change the behaviour)
I remember that I was trying “udevadm settle” in %pre and this was returning
fast and that’s why I thought that it was not waiting for some slow udev event.
I had another look.
I added a sleep 600 and removed the parted from parted (600s should be
plenty of time for detection)
Here is my interpretation:
The kernel *did* detect the partitions in early initramfs
…
Aug 31 14:19:50 localhost kernel: sda: sda1 sda2
Aug 31 14:19:50 localhost kernel: sd 0:0:0:0: [sda] Attached SCSI disk
…
If I add rd.break kernel parameter I can see that the devices are there.
But after switching root (pivoting) they are gone. I do not know if this
is expected or not.
So while %pre is running sda1 and sda2 are not present given that I did
not trigger udev with parted or similar.
After %pre is finished it is detecting sda1 and sda2 again, and it is
finding the VG and the LVs, but then it is stopping the VG (which is what
I find strange) and throwing the error
…
initramfs
…
Aug 31 14:19:50 localhost kernel: sda: sda1 sda2
Aug 31 14:19:50 localhost kernel: sd 0:0:0:0: [sda] Attached SCSI disk
…
pivot root filesystem
…
running pre (10 minutes sleep)
…
Aug 31 14:30:14 test kernel: sda: sda1 sda2
…
Aug 31 14:30:15 test org.fedoraproject.Anaconda.Modules.Storage[1903]: DEBUG:blivet: DeviceTree.handle_device: name: lvm.vg1-root ; info: {'DEVLINKS': '/dev/disk/by-uuid/9c60e33e-03e0-42c4-a583-868f4fd1b2b4 '
…
Aug 31 14:30:15 test org.fedoraproject.Anaconda.Modules.Storage[1903]: INFO:program:Running [36] lvm vgchange -an lvm.vg1 --config= devices { preferred_names=["^/dev/mapper/", "^/dev/md/", "^/dev/sd"] } log {level=7 file=/tmp/lvm.log syslog=0} …
…
Aug 31 14:30:21 test org.fedoraproject.Anaconda.Modules.Storage[1903]: Logical volume "root" given in logvol command does not exist.
…
If someone is interested, I created a gist with the kickstarts and logs at
https://gist.github.com/610acf7379f48d0e5c38f4edb9cda176
(you can clone it with git)
I found no obvious error, but there is a lot of stuff and I could have
missed something easily.
Given that anaconda sees the LVs, do you still think that it is a kernel
problem or the storage too slow?
Best Regards, Markus
and thanks too all who took the time answering.
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