ubuntu-phone team mailing list archive

[Zoltán Balogh <zoltan.balogh@xxxxxxxxxxxxx>]

Hi,

The root file system we use to build and package apps with the SDK are 
chroots wrapped around with schroot and click. This chroot contains the 
application development framework and documentation.

The purpose of this chroot is to make the phone APIs, libraries 
available for the developers who might be on Trusty or on Utopic. So the 
chroot contains the stuff what is on the real device.

Right now we create these chroots on the first start of the Ubuntu SDK.  
There are few problems with this flow:

1. The `click chroot create` uses schroot debootsrap what downloads the 
core bootsrap and installs the requested framework. It means about 1.7GB 
downloaded data and hundreds of .deb packages. It is a slow and fragile 
process.

2. The schroot debootstrap creates the actual snapshot of the Ubuntu 
series, so it is working with a rather fluid base. The Utopic based RTM 
target is stable, but the development release, as expected is a 
constantly changing target. So we hardly have a solid common base.

We have been talking about the possibility of releasing the SDK 
frameworks in single downloadable static  images.

The benefits of such SDK distribution model are:

1. Smaller and single downloadable root file system

2.  Static and versioned images what we could release together with the 
device images

I made a simple pilot project to demonstrate how the real implementation 
would look [3]

This project have two scripts:

1. create_static_schroot.sh

This script is for

1.1 creating static image: sudo create_static_schroot.sh -c -a armhf -f 
ubuntu-sdk-15.04
1.2 installing the created image: sudo create_static_schroot.sh -i 
click-ubuntu-sdk-15.04-armhf-amd64.tar.gz
1.3 downloading and installing the image: create_static_schroot.sh -d -a 
armhf -f ubuntu-sdk-15.04

The -h parameter shows all the available options.

The static images are hosted on people.canonical.com [2]

Right now there are both i386 and armhf images for 15.04

2. test_static_chroot.sh

This script is for banchmarking the click chroot creation and the 
create_static_schroot.sh -d -a armhf -f ubuntu-sdk-15.04

I have asked folks around to help with the benchmarking, because the 
chroot creation in any case depends on the bandwidth.

I got results from DanChapman, zbenjamin, kalikiana and zsombi plus my 
own test [1]. The result is that downloading from the 
people.canonoical.com the image and setting it up for schroot takes 
40-60% of the time of creating a click chroot.

Please give these scripts a try and let's discuss about how to go 
forward. I would definetly suggest to work out this model a bit more and 
start hosting SDK images alongside with the other system images and 
teach either the Ubuntu SDK or the click itself to optionally use the 
static images instead of the dynamically created bootstraps.

cheers,

bzoltan

[1]  http://paste.ubuntu.com/10257872/ 
http://pastebin.ubuntu.com/10257860/ http://paste.ubuntu.com/10257687/
[2] http://people.canonical.com/~bzoltan/static_chroots/
[3] lp:~bzoltan/+junk/static_chroots