Re: PRoot Isar summary

[Alexander Smirnov <asmirnov@ilbers.de>]

Hi,

On 11/10/2017 09:59 PM, Jan Kiszka wrote:
> On 2017-11-09 10:57, Alexander Smirnov wrote:
>> Hello everybody,
>>
>> I've tried to completely switch Isar to PRoot, so here are the problems
>> I've faced with:
>>
>> 1. PRoot doesn't work with UID/GID, all the files in PRoot are owned by
>> root. The command 'chown' doesn't have any effect.
>>
>> 2. Some system commands are failed in PRoot: passwd, chpasswd. I see
>> message: System error, no other clues (but for Wheezy these commands work).
>>
>> 3. mkfs.ext4 doesn't work under proot, lots of files are dropped in
>> resulting image.
>>
>> So, summary:
>> ============
>>
>> 1. PRoot could be an intermediate option for:
>>   + Buildchroot creation.
>>   + Packages building.
>>   - Drawback: works slowly.
> 
> Aren't issues 1 and 2 from above affecting these use cases as well?
> 

For now I don't have any facts about problems with buildchroot, but my 
test includes only 'hello' and 'example-raw' applications.

  - Regarding UID/GID, what I've seen for now, these manipulations are 
done in postinst scripts.
  - Passwd/chpasswd commands are also used in postinst scripts (for 
example initrd package), there is no need to have passwords in 
buildchroot because we are working under root.

So, roughly speaking, buildchroot is only needed to compile and pack the 
binary package, what doesn't require multi-UID/GID and passwords support.

But for sure, it needs to build much more real packages to have more 
precise statistics. :-(

So I've created dedicated branch 'asmirnov/proot' for possible 
experiments in future.

>>
>> 2. For image generation the other tool should be considered.
>>
> 
> What is plan B now? Plan C remains falling back to VM builds, I suppose.

So there are 2 options remain for evaluation:
  - fakeroot
  - pseudo

I'd like to evaluate these tools for the features, that are uncovered now:

  - rootfs with UID/GID support: in general PRoot is able to generate 
multistrap rootfs with just *upacked* Debian packages, all the problems 
occur when I try to run 'dpkg-configure -a' inside this rootfs.

  - ext2fs image generation (AFAIK this already is supported by Yocto, 
but unfortunately I don't know too much, I need to take a look first).

 From this evaluation I'd like to get two points:

1. Could we somehow implement quick PoC to drop 'sudo' for Isar. This 
PoC could be based on several tools in parallel.

2. If the item above is possible - then choose one dedicated tool and 
try to adapt it for our needs.

Alex