[pve-devel] [PATCH pve-kernel-meta/proxmox-ve v3] proxmox-boot: add kernel pinning functionality (#3761)

[Fabian Grünbichler]

On February 11, 2022 4:15 pm, Stoiko Ivanov wrote:
> changes v2->v3:
> * incoroporated Fabian's and Thomas' feedback - huge thanks:
> ** changed `p-b-t kernel next-boot <ver>` to `p-b-t kernel pin <ver> --next-boot`
> ** improved usage output
> ** style-fixes to proxmox-ve apt-hook
> ** 'untaint' the fd fetched from the environment in proxmox-ve apt-hook
> * fixed a glitch in the non p-b-t booted case (next-boot pin followed by a
>   permanent pin cause the next-boot to be ignored)
> * output of `p-b-t kernel list` now only prints pinned versions if they are set
> 
> original cover-letter for v2:
> changes v1->v2:
> * incorporated the feedback on the v1 (by Aaron and Fabian - huge thx!):
> ** a next-boot pin is now handled independently from a pin - i.e. if you
>    both pin a kernel and set one for the next-boot - the system afterwards
>    keeps the pinned version (instead of the latest)
> ** change from modifying /etc/default/grub to creating a snippet in
>    /etc/default/grub.d/proxmox-boot-pin.cfg - I did not see a need for having
>    two pinning files there (since they get written both at each relevant
>    invocation anyways - thus also no need for prefixing with y_ and z_
> ** the semantics of unpin changed (it now takes an optional argument to
>    remove the next-boot-pin only (made the cleanup-service cleaner)
> ** added a check to the apthook in proxmox-ve as Fabian suggested
> * changed the semantics of get_first_line - to check for file existence
>   itself, since it makes using it shorter at almost all call-sites
> * fixed two perlcritic warnings in the pve apthook (which is quite
>   independent of the series)
> 
> again tested on 3 VMs (ext4, zfs+uefi, zfs+legacy) - but would be grateful
> if you find some use-case apart from - pin permanent, pin next-boot, reboot,
> reboot.

for the whole series:

Reviewed-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>
Tested-by: Fabian Grünbichler <f.gruenbichler at proxmox.com>

not applying for now in case we want to roll this out together with the 
final version of the other series.

> 
> 
> original cover letter of v1:
> The following series adds:
> * proxmox-boot-tool kernel pin <kabi-version> (to permanently set the
>   default entry of the respective bootloader)
> * proxmox-boot-tool kernel unpin (to undo a previous pin)
> * proxmox-boot-tool kernel next-boot (to do a pin+touch a file, which causes
>   an unpin on next boot)
> 
> This is the first functionality which is available for 'regular grub-setups'
> (i.e. systems setup with lvm-thin with our ISO or systems installed on top
> of plain debian) as well.
> 
> The first two patches are cleanup+refactoring (and should not change any
> functionality)
> 
> The choices (those I think might benefit from a bit of feedback) for this
> implementation were:
> * for grub - automaticially rewrite '/etc/default/grub' (as this is where
>   I'd look to check whether some default is set)
> * for systemd - set the entry in the loader.conf and not in the efivars
>   (`bootctl set-default/set-once`) - mostly from my bias towards config
>   files instead of UEFI vars (depending on implementation quality of the
>   UEFI) - another reason was to keep the implementation close for both
>   boot-loaders
> * for p-b-t booted systems the need to run `p-b-t refresh` manually
>   afterwards (following the behavior of `p-b-t kernel add/remove`) could
>   be changed to invoking the refresh directly (as with non-p-b-t booted
>   systems). Especially since it might make sense to 'add' multiple kernels
>   and then do the mount+copy+configupdate only once, whereas you can only
>   pin on version anyways
> 
> Tested on three VMs installed from the 7.1 ISO (UEFI+ZFS, legacy+ZFS,
> UEFI+lvm-thin).
> 
> pve-kernel-meta:
> Stoiko Ivanov (4):
>   proxmox-boot: return empty if file does not exist in get_first_line
>   proxmox-boot: fix #3671 add pin/unpin for kernel-version
>   proxmox-boot: add --next-boot option kernel pin command
>   proxmox-boot: add pin/unpin functionality for non-p-b-t systems
> 
>  bin/proxmox-boot-tool                     | 97 +++++++++++++++++++++++
>  debian/pve-kernel-helper.install          |  1 +
>  debian/rules                              |  3 +
>  proxmox-boot/Makefile                     |  4 +
>  proxmox-boot/functions                    | 45 +++++++++++
>  proxmox-boot/proxmox-boot-cleanup.service | 13 +++
>  proxmox-boot/zz-proxmox-boot              |  8 ++
>  7 files changed, 171 insertions(+)
>  create mode 100644 proxmox-boot/proxmox-boot-cleanup.service
> 
> proxmox-ve:
> Stoiko Ivanov (3):
>   apt-hook: fix perlcritic warnings
>   apt-hook: verify that fd is numeric
>   apt-hook: add check preventing the removal of pinned kernels
> 
>  debian/apthook/pve-apt-hook | 36 +++++++++++++++++++++++++++++++++---
>  1 file changed, 33 insertions(+), 3 deletions(-)
> 
> -- 
> 2.30.2
> 
> 
> 
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