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Platform SDK

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Revision as of 17:14, 10 August 2013 by Mike7b4 (Talk | contribs)

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Quick install using Virtual machine or install on a linux host

The platform SDK aims offers an image that can be run like a virtual machines using guide Platform_SDK_on_VirtualBox, which contains tools like Scratchbox2, MIC (image creator), spectacle, osc, qemu, etc, to make it easier for a developer to work with Mer.

Here is a quick guide if you want to install on linux host directly: (does not cover Basic tasks):

The SDK consists of a directory tree and when you 'mount' the SDK you will link your home directory, root directory and any data directories within this tree.
Because of this you *MUST* 'umount' the SDK before deleting it - if you don't then you *WILL* lose data.

cd $HOME; curl -k -O;
sudo mkdir -p /srv/mer/sdks/sdk;
cd /srv/mer/sdks/sdk;
sudo tar --numeric-owner -p -xjf $HOME/mer-latest-sdk-rolling-chroot.tar.bz2;
echo 'alias sdk=/srv/mer/sdks/sdk/mer-sdk-chroot' >> ~/.bashrc ; exec bash;
echo 'PS1="MerSDK $PS1"' >> ~/.mersdk.profile;
sdk mount;
sdk enter;

It recomended read below for details, WARNINGS, pre-requisites and details on installing extra tools etc...

Mer platform SDK

To avoid any confusion, there are two types of SDKs: Application SDKs and Platform SDKs. Application SDK's are the ones that deal with Qt applications and libraries, HTML5, etc, while Platform SDK's are for developing the platform, compiling native code and other things revolving around the platform developer/hacker needs.

The platform SDK offers an image that can be run like a virtual machine (typically), which contains tools like gcc, Scratchbox2, MIC (image creator), spectacle, osc, qemu, etc, to make it easier for a developer to work with Mer.

The initial download contains:

  • Mer development tools
  • Mer image creation
  • Mer OBS development

You can also install :

  • Cross-build tools for armv6l armv7l armv7hl mipsel
  • Mer debug tools
  • Mer testing tools
  • Mer python development
  • Mer ruby development

You may also like to contribute to developing the SDK.

Using the platform SDK

SDK Requirements

The chroot SDK will run on most modern linux machines. It needs:

  • Linux distribution (one in a virtual machine works well), running 2.6.37 or newer kernel
  • about 400Mb free space to install
  • the filesystem storing the SDK should be mounted using the suid option (Note: it looks like for security reasons the recent ecryptfs versions will automatically use and enforce nosuid, and this can't be overridden)
  • hundreds of Mb for rpm caches for osc and mic
  • Generic x86 CPU
  • user must have sudo rights


The SDK consists of a directory tree and when you 'mount' the SDK you will link your home directory, root directory and any data directories within this tree.

Because of this you *MUST* 'umount' the SDK before deleting it - if you don't then you *WILL* lose data.

If you are unfamiliar with bind mounts, the safest way to uninstall is to reboot your machine and remove the SDK *BEFORE* using the sdk 'mount' command.

Please do not be alarmed by this - we're simply letting you know that running an "rm -rf" command in the wrong place is dangerous. It's better to explain this in big letters than risk someone losing data by mistake :)

Obviously people working on SDK development and testing should take particular care.

Installation / setup

The platform SDK is provided as a rootfs tarball that contains essential tools for Mer platform development along with a helper script to enter the rootfs.

Filesystem requirements:

  • The SDK can be installed to any location with enough space - we'll use /srv/ as per the Linux FHS (feel free to adapt the commands to use any other location).
  • The installation path must contain an intermediate directory called 'sdks' which only has Mer SDKs inside. eg /srv/mer/sdks/sdk/...
  • The SDK must not be on a nosuid filesystem - note automounted usb drives typically have this set

To setup the SDK:

  • Download the latest stable SDK rootfs tarball.
cd $HOME
curl -k -O
  • Create directory for the SDK rootfs and extract the tarball as root or with sudo
sudo mkdir -p /srv/mer/sdks/sdk
cd /srv/mer/sdks/sdk
sudo tar --numeric-owner -p -xjf $HOME/mer-latest-sdk-rolling-chroot.tar.bz2

SDK control script

The platform SDK rootfs contains a helper script to enter the chroot named 'mer-sdk-chroot'. The helper script is located in the root directory (/) of the rootfs. It requires you to have sudo ability.

As mentioned, the SDK is location independent so it uses the location of the helper script to determine which SDK to enter.

Connect the SDK using 'mount'

You need to connect the SDK before using it. This only needs to be done once (well, once each time you boot your machine) and it connects things like /proc and $HOME in the SDK. It also links /parentroot of the SDK to your normal / directory.

Under normal use the SDK does not need to be disconnected. As per the warning above, you should disconnect using 'umount' before removing the SDK (see remove/disconnect info below)

To connect run:

/srv/mer/sdks/sdk/mer-sdk-chroot mount

You can now use the SDK from multiple terminals at once.

Entering chroot

Before entering the SDK you may want to make an SDK equivalent of ".profile" to give you a nice prompt to remind you that you are in the SDK. This also reads the bash autocompletion scripts from inside the chroot.

cat << EOF >> ~/.mersdk.profile
PS1="MerSDK \$PS1"
if [ -d /etc/bash_completion.d ]; then
   for i in \$(ls /etc/bash_completion.d/*);
	. \$i

To enter the rootfs with the helper script run

/srv/mer/sdks/sdk/mer-sdk-chroot enter

You should find that you are operating under your normal username and that your home directory is available as /home/<username> and any other mountpoints are mounted under /parentroot/*

You have sudo rights automatically. If sudo fails within the sdk, make sure that the filesystem the sdk is on is not mounted with the "nosuid" parameter. "mount" on the host system gives you this information, add "suid" as parameter in fstab, if necessary.

Useful Alias

If you tend to use a single instance of the sdk then this alias is useful

 echo alias sdk=/srv/mer/sdks/sdk/mer-sdk-chroot >> ~/.bashrc ; exec bash

Basic tasks

Building an image

ATTENTION: If you are making image for i586 target, use --arch=i686 !

Mer images are build using mic image creator. Mic takes a kickstart file that defines the image to be created as input. To create a Mer image with the platform SDK simply call mic as you would do on any other system. For example

As a test this should make a new local SDK rootfs image:

Check: for the name of the latest KickStart file and use it in the first command below:

  • Work around the recent shutdown of MeeGo repositories.
echo | sudo tee -a /etc/hosts
for chroot version:
curl -k -o mer-latest-sdk-rolling-chroot.ks
sudo mic create fs mer-latest-sdk-rolling-chroot.ks -o . --pkgmgr=zypp --arch i486 --pack-to=mer-latest-sdk-rolling-chroot.tar.bz2
for VM version:
curl -k -o mer-next-sdk-rolling-vm.ks
sudo mic create raw mer-next-sdk-rolling-vm.ks -o . --pkgmgr=zypp --arch i486

Please check bugzilla if you encounter problems:

extlinux issue

Running osc

(This section needs to be improved)

Since your home directory has been linked into the SDK then osc commands should work as normal.

osc -A API_URL ls

Where API_URL can be:      Mer Community OBS   Mer's continous integration OBS (not for regular use)

or the API url for your own, or your company's OBS.

Compiling with the SDK

Mer and the SDK uses Scratchbox2 as a cross compile tool; it can be installed into a minimal SDK by installing a cross-build environment suitable for your project.

You should install one or more of the following SB2 patterns to get a suitable environment:

sudo zypper in -t pattern Mer-SB2-armv6l
sudo zypper in -t pattern Mer-SB2-armv7l
sudo zypper in -t pattern Mer-SB2-armv7hl
sudo zypper in -t pattern Mer-SB2-armv7tnhl
sudo zypper in -t pattern Mer-SB2-mipsel

NOTE: in case of facing "not enough disk space left" or similar the problem is most probably that the kernel on your host is too old. To run Mer SDK you should be running kernel 2.6.37 or newer on your host.

These patterns provide:

  • sb2 configurations
  • qemu
  • gcc and binutils for your architecture

Once the SDK is setup, see the documentation on using the Platform SDK and SB2


The SDK includes tools needed to create rpm packages for Mer.


Hosting repositories

To make installing created packages easier you can host your own rpm repository with the SDK and install packages to your target device from there.


SDK contents

The platform SDK's rootfs has some useful packages preinstalled that are listed below. If you're missing something you can use zypper to install the needed extra packages or if not available in the repositories compile them yourself.

  • osc and build
  • mic
  • spectacle
  • vim

Adding New Tools

New tools can be installed using

sudo zypper in <package>


sudo zypper in -t pattern <pattern>

The following patterns are available:

Mer-SB2-armv6l, Mer-SB2-armv7l, Mer-SB2-armv7hl, Mer-SB2-mipsel 
Cross-build tools for various architectures
A range of low-level debug tools
testrunner, eat and qttas
all your slithery needs
to add sparkle

Zypper search is useful to find available packages.

Upgrading the SDK

Don't just do zypper up!

The SDK image is (as of 5 June 2012) pinned to specific static repositories and upgrades are carried out using "sdk-upgrade" which allows the repos to be updated to latest, next or set to point to any Mer Core/SDK release pairing.

Recent SDK versions no longer have "sdk-upgrade" and you will need to run "sdk-version"(with different arguments) in order to upgrade different components of the SDK.

Upgrading Older SDKs

(ie one without sdk-version or sdk-upgrade tool)

You may be prompted to remove the unstable Tools:Testing repo - and you really should as that's now going to be used by the Tools team for sharing experimental packages. Then follow the steps indicated.

Old SDKs which don't have sdk-version should execute these steps before moving on to the appropriate upgrade process:

sudo zypper ref
sudo zypper in sdk-chroot

Now run the following command

sudo sdk-upgrade

If it fails skip this part; if it succeeds then run:

sudo zypper ref
sudo zypper in sdk-chroot

This release needs to install the correct script and then exit/re-enter the SDK:

# unmount, re-mount and re-enter the SDK to clean up
/srv/mer/sdks/sdk/mer-sdk-chroot umount
/srv/mer/sdks/sdk/mer-sdk-chroot mount
/srv/mer/sdks/sdk/mer-sdk-chroot enter

Now move on to the normal upgrade

Workaround for "Couldn't resolve host ''"


Then run

sudo sdk-version --latest --go

Normal Upgrade

Simply run:

sudo sdk-version --latest --go

Documentation for sdk-version

   usage:  [--latest | --next] [--core <release>] [--sdk <release>] [-h|--help]
    By default reports the current versions from the repos
    Alternatively updates the zypper repos to point to the "latest",
    "next" or specified Mer / SDK releases. It does not run zypper
    ref or zypper up by default (use --go for that).
    --core <release> : Use Mer Core <release>
                       eg: --core 0.20120517.1
                       <release> can be "next" or "latest" from
    --sdk  <release> : Use SDK/Tools <release>
                       eg: --sdk 0.5.1
                       <release> can be "next" or "latest" from
    --latest : short for: --sdk latest --core latest
    --next : short for: --sdk next --core next 
    --go : actually run the zypper upgrade

Advanced details

Documentation for mer-sdk-chroot

The usage for the helper script is:

   usage: mer-sdk-chroot [<enter>] [-u <user>] [-r <SDK root path>]
          mer-sdk-chroot mount [-u <user>] [-m <all|none|root|home>] [-r <SDK root path>]
          mer-sdk-chroot umount [-r <SDK root path>]

      This is the Mer chroot SDK.
      For information see

      The SDK has 3 commands:
         enter (default)

        Used to enter the SDK and begin working. The SDK bash shell is a
        login shell. See below for .profile handling
        Must be preceded by a 'mount' to setup the SDK.
        May be used in multiple terminals and simply enters the

        Used to setup the SDK mountpoints. Only needed once per login

        Used to clean up the SDK mountpoints before removing the SDK.


      -u  System user to link into SDK (not needed if using sudo)
      -m  Devices to bind mount from host: none, all (default)
          root, home
      -r The root of the SDK to use - normally derived from the
         pathname of mer-sdk-chroot


     Entering the SDK runs the user's normal .profile and any (SDK)
     system profile entries. It will not execute the host's system
     profile entries.

     The environment variable MERSDK is set to 1 to allow .profile to
     detect the SDK.

     If the user has a ~/.mersdk.profile then it is sourced after the
     normal .profile handling (this allows the common use case of
     setting a profile to be handled).


     If the user specified has a .mersdkrc in their $HOME, it will be
     sourced to allow hook functions to be defined. Hooks are run as
     root. No commands should be executed immediately.

     These hooks are usually used to define symbolic links from any
     /parentroot/data type filesystems into the SDK root to setup
     system specific shared caches or filesystem layouts etc

Sharing mic and osc caches

You can use the ~/.mersdkrc file to check and link the standard mic and osc cache directories to those in parentroot.

Note that multiple *concurrent* instances of mic should not share the same cache (it's OK to share from different SDKs and different terminals provided they're not running and accessing the cache at the same time).

Here's some code you can use in ~/.mersdkrc to share a mic cache:

    if [[ ! -e ${sdkroot}/var/tmp/mic ]]; then
        mkdir -p ${sdkroot}/var/tmp/mic
    if [[ ! -e /parentroot/var/tmp/mic/cache ]]; then
        mkdir -p /parentroot/var/tmp/mic/cache
    if [[ ! -e ${sdkroot}/var/tmp/mic/cache && ! -h ${sdkroot}/var/tmp/mic/cache  ]]; then
        ln -s /parentroot/var/tmp/mic/cache ${sdkroot}/var/tmp/mic/cache

In your ~/.oscrc file there is a line:

 packagecachedir = <something>/build-pkg-cache

If this is under $HOME then it will be shared anyway; otherwise do something similar to the mic cache code above.

Multiple SDKs

You should be able to install and connect to multiple SDKs at the same time.

.mersdk.profile tricks

work around bug #554

To work around bug #554 add the following to ~/.mersdk.profile (e.g. Fedora >= 17 needs that):

export PATH=$PATH:/sbin


If you want SSH_AUTH_SOCK to be exported in Mer SDK you can do the following.

Add this to your ~/.mersdkrc, set YOURHOME to your home dir, NOTE: this part of code is run as root, but still contains the users SSH_AUTH_SOCK! So $HOME will point to /root!

function enter_sdk {
    echo "set SSH_AUTH_SOCK env..."
    cp $YOURHOME/.mersdk.profile $YOURHOME/.mersdk.profile.tmp
    sed "s#^SSH_AUTH_SOCK_TEMP=.*#SSH_AUTH_SOCK_TEMP=${SSH_AUTH_SOCK}#" $YOURHOME/.mersdk.profile.tmp > $YOURHOME/.mersdk.profile
    rm $YOURHOME/.mersdk.profile.tmp

Add this to your ~/.mersdk.profile:

SSH_AUTH_SOCK_TEMP=/tmp/#this line will be overwritten!
export SSH_AUTH_SOCK="/parentroot${SSH_AUTH_SOCK_TEMP}"

Removing and disconnecting the SDK

Under normal use the SDK does not need to be disconnected; it's only usually needed when you want to remove an instance of the SDK.

To disconnect run:

/srv/mer/sdks/sdk/mer-sdk-chroot umount

Be sure that the bind-mounts(especialy the home directory) are all umounted after you disconnect the SDK. You can use 'cat /proc/self/mountstats' to check it. If it is not umounted cleanly, you should umount it manually after you exit the chroot environment.

The SDK does warn you if umounts fail. It also uses 'lazy' umounts which means that the mountpoints will go away as soon as the kernel can clean them (typically when processes exit or terminals cd out of the mounted directories.)

Once the SDK has been cleanly unmounted, it may be removed manually.

Note that the mountpoint:


will stay in the mount list all the time - this is intentional. Also note that it can sometimes appear to show a mount to the same device as another mountpoint (eg /) depending on your distro's configuration. (See bug 328 for details)

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