[PATCH v2] base-files: restore status of system-services after sysupgrade

[Hannu Nyman]

Martin Schiller kirjoitti 12.1.2021 klo 9.25:
> On 2021-01-11 23:07, Sven Roederer wrote:
>> Restore the status of the system-services after sysupgrade.
>> Create a file with the status of all known services and keep it during
>> upgrade. After upgrade run a uci-default script to restore every
>> single service.
>
> Doing the restore in an uci-default script is to late, because then you
> are already in the procd rcS helper "loop" and new added init links
> won't get called.
>
> Also, have you thought about a backup/restore of the configuration?
> The whole thing should/must work there as well.
>
> I would do the restore at the end of the pre-init stage.
>
> Martin


My two cents to the discussion:

* I assume that a small minority of users actually disable services, or at 
least disable several services, so defaulting to "lets by default always 
store status of all services" sounds like overkill.

* Backuping always info that the dozens of standard services are enabled 
sounds unncessary. As services are installed by default as "enabled" to the 
image, it might make sense to store only info about "disabled" services and 
disable those when restoring the backup in sysupgrade.  (Re-enabling the 
already enabled services is unnecessary.)  That would also help to keep the 
amount of new backup info small.

* make clear in sysupgrade script help texts and documentation that 
saving/restoring service status depends on "keep settings". If settings are 
not kept, the service status can not be copied in sysupugrade as there is no 
sysupgrade.tar.gz to be passed. (And naturally it would not even make sense 
to e.g. revert network settings to defaults but keep selected network 
services disabled. Easy to cause soft-bricks that way.)