[plug] Debian 10-11 upgrade issues

[Onno Benschop]

Several things come to mind.

Have you considered nested virtualisation, which might give you what you
need.

Also ZFS apparently offers snapshots on a live disk, but I've only ever
heard of it, never seen it.

As a data-point, since I don't know your specific requirements, I'm running
VMware on a macOS workstation that has guests doing all the work. One of
those guests is a bare bones Debian machine acting as a Docker host where
most of the actual work happens.
--
finger painting on glass is an inexact art - apologies for any errors in
this scra^Hibble

()/)/)() ..ASCII for Onno..

On Wed, 28 June 2023, 12:01 Dean Bergin, <dean.bergin at gmail.com> wrote:

> Hello Nick!
>
> I pulled the trigger too soon.
>
> I dug a bit deeper and discovered the problem is indeed mdadm itself, or
> more specifically, the config file.
>
> It turns out that either mdadm or kernel behaviour appears to have changed
> between versions, so I commented out the apparently-still-valid 'DEVICE'
> section in mdadm.conf then rebooted and I'm now back in business! 😁
>
> Thanks for the links though much appreciated. On that note, does
> anyone have any recommendations on doing bare-metal snapshot/restores at
> the root FS (preferably live)?
>
> I'd love to find a solution to managing a bare-metal host like a VM to
> avoid situations like this in future.
> I can't really operate the host as a VM as it's a kind of hyperconverged
> hypervisor host, so I generally require bare-metal and direct access to all
> devices but the GPU.
>
>
> Kind Regards,
>
> *Dean Bergin*.
>
>
> On Wed, 28 Jun 2023 at 11:27, Nick Bannon <nick at ucc.gu.uwa.edu.au> wrote:
>
>> On Wed, Jun 28, 2023 at 10:03:54AM +0800, Dean Bergin wrote:
>> > I'm wondering if anyone can offer some sage advice around an issue I
>> have
>> > post-upgrade of a homelab server I maintain.
>> > I'm stuck in emergency mode and it looks as though my LVM
>> (device-mapper)
>> > mounts aren't available.
>>
>> Heya, Dean! Sounds fixable, good luck. Can you boot with an "old" kernel?
>>
>> While it's usually possible to get away with just the installer
>> "rescue" mode, I find it's more reassuring to reach for a different
>> "live boot" at this stage and interactively use https://www.finnix.org/
>> (small, Debian "testing" based, and also great for a headless server)
>> or https://www.debian.org/CD/live/ . Either the latest, or occasionally
>> going back to a version that more closely matches your current system.
>>
>> Boot it, let it scan for what's available, then interactively experiment
>> to find exactly what you need to get your system mounted and
>> self-bootable.
>>
>> > Before upgrading, I did have crypto-mount (or something) enabled, which
>> > produced errors but did not prevent boot as I never encrypted the
>> > underlying raid block device md0 (it was always planned but never
>> > implemented, so it was skipped when building the server and I never
>> > disabled the crypto boot service).
>>
>> It sounds like that specifically was "just" a harmless warning? We need
>> to find the errors in console output, or `dmesg`, or what's totally
>> missing that "ought" to be there, like a loaded working driver for your
>> storage hardware (`lspci`/`lshw` ?).
>>
>> Maybe those devices were missing because of an `mdadm` error that
>> scrolled past unnoticed, or a missing driver module in the `initramfs`,
>> and it might be easier to see from a running live USB what was missing.
>>
>> ( If the LVs are missing (`lvs`/`vgs`/`pvs`), the md0
>> has probably not been assembled. Maybe that failed because the devices
>> under md0 were missing, so that needs to be fixed before `vgchange -ay`
>> will help. )
>>
>> There may be some known relevant issues that got written down in the
>> "Upgrade" chapter 4 or "Issues to be aware of" chapter 5 of:
>> https://www.debian.org/releases/oldstable/amd64/release-notes/
>> https://www.debian.org/releases/stable/amd64/release-notes/
>>
>> [...]
>> > I'm seeking some advice to try to quickly fix this before I consider
>> > rebuilding. I do have a copy of /etc before upgrading FWIW.
>>
>> Good, could be handy to compare or know what devices or filesystem UUIDs
>> to look for.
>>
>> Nick.
>>
>> --
>>    Nick Bannon   | "I made this letter longer than usual because
>> nick-sig at rcpt.to | I lack the time to make it shorter." - Pascal
>> _______________________________________________
>> PLUG discussion list: plug at plug.org.au
>> http://lists.plug.org.au/mailman/listinfo/plug
>> Committee e-mail: committee at plug.org.au
>> PLUG Membership: http://www.plug.org.au/membership
>>
> _______________________________________________
> PLUG discussion list: plug at plug.org.au
> http://lists.plug.org.au/mailman/listinfo/plug
> Committee e-mail: committee at plug.org.au
> PLUG Membership: http://www.plug.org.au/membership
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.plug.org.au/pipermail/plug/attachments/20230628/e21ae2aa/attachment.html>