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Platform SDK on VirtualBox

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The Mer VM SDK is intended for use with QtCreator, on non-linux machines and on machines where a chroot-based SDK is not desired.

The SDK has 3 significant areas:

  • Qt Creator: this runs on your host machine and (with the Mer plugin) allows you to manage application development, the SDK VM and your targets.
  • SDK Virtual Machine: This contains all the Mer development toolchains and tools
  • Development Target(s): these contain QML components, headers and libraries for your targets (eg Nemo, Plasma Active or vendor supplied targets)


The Mer SDK uses Oracle's VirtualBox as the virtualisation engine. The website at has a a lot of useful information.

Other virtualisation solutions should work without any issues. The main requirement is the ability to support shared folders.


  • VirtualBox version 4.18 or higher (should be 4.x).
  • Suitable hardware with correct BIOS settings to allow VirtualBox to run
  • Linux host (we intend to support other OSes 'soon')

Prepare Image

Download the SDK vmdk from

Then unzip the image (it's a very large file)

bunzip2 mer-sdk*vdi.bz2

Create the VM

Run the VirtualBox manager and create a new machine called MerSDK with Linux/2.6 (32bit)


For larger builds allocate a substantial amount of memory (eg 2048Mb)

Select "Use existing hard disk" and pick the vdi you just downloaded/created

Now select create to make the VM.

Don't boot/start the VM until you have setup the shared folders or they will not be accessible.

Setting up and Networking

Select the MerSDK VM and then pick Settings

In System/Motherboard enable IO APIC.

In System/Processor enable PAE/NX and allocate as many CPUs as your host has.

This is not an emulator so there is no point setting any special Display settings.

In Networking set Adapter 1 to "NAT" ( see ) since your VM will need to access the internet to perform updates.

Since it will need to act as a server for your local host we must setup port-forwarding too.

Select 'Advanced' and then 'Port Forwarding'. In the rules box add:

Name: guestssh
Protocol: TCP
Host Port: 2222
Guest Port: 22


Name: guestwww
Protocol: TCP
Host Port: 8080
Guest Port: 9292


Storage and Sharing your home, source and caches

Make sure /srv/mer/targets exists and is owned by you.

sudo mkdir -p /srv/mer/targets
sudo chown $USER /srv/mer/targets

Under Settings -> Shared Folders (example screenshot below) add two Machine Folders with the

Folder path: <your home directory eg /home/lbt>
Folder name: home

and if you want to login via ssh to mersdk you also need to share your private mer-qt-creator-rsa key folder: Notice! this is a security risk if you let others login to the same mersdk you should NOT use $USER/.ssh folder. instead move mer-qt-creator private key elsewhere. Because you don't want others to see the other private keys.

Folder path: <your home directory/.ssh eg /home/lbt/.ssh>
Folder name: ssh
Read Only: true


Folder path: /srv/mer/targets
Folder name: targets

Do not tick the 'automount' box as that simulates a removable media device which will not work.

Note:Use the folder names as specified, else the VM may not boot.


The shared folder called 'home' will be mounted as the sdk user's 'mersdk' $HOME directory as the SDK boots. The 'targets' shared folder will be mounted as /srv/mer/targets and will store target device headers and qml files used by Qt Creator.

You may want to share additional source and cache directories from your host.

Symbolic Links on shared folders

To enable Virtualbox to support symlinks run this command before launching the VM:

 VBoxManage setextradata MerSDK VBoxInternal2/SharedFoldersEnableSymlinksCreate/home 1 
 VBoxManage setextradata MerSDK VBoxInternal2/SharedFoldersEnableSymlinksCreate/targets 1

Ubuntu DNS

Ubuntu 12.10 and above has local DNS proxy running in address not . To enable DNS work with Ubuntu

VBoxManage modifyvm MerSDK --natdnshostresolver1 on

Running the SDK VM

You may now start the SDK VM. It will start an ssh service which can be accessed as:

ssh -p 2222 root@localhost

The root password is "rootme".

Ensure your ~/.ssh/authorized_keys files has your own public key in it and you can access mersdk user with no passwd:

cat ~/.ssh/ >> ~/.ssh/authorized_keys  # works if your key is in ~/.ssh/ (type this on your host)
ssh -p 2222 mersdk@localhost

This is important for QtCreator to work seamlessly.

If you get errors such as "Agent admitted failure to sign using the key" when testing from the command line "ssh -p2222 mersdk@localhost" or later Qt Creator can't create connection to VM try following

ssh-keygen -trsa (don't type a password when prompted)
cat ~/.ssh/ >> ~/.ssh/authorized_keys

(in vm, your host home dir is mounted at /home/mersdk (mersdk's home on vm), so your ~/.ssh/autorized_keys is used for authorizing access to mersdk@localhost:2222)


The SDK uses the Virtualbox shared folder mechanism which needs to support files stored on various hosts and does not support certain features:

  • Symbolic links (see workaround above for linux hosts)
  • Memory mapped (mmap) files

If this is a problem then virtualbox can be configured to store data on dedicated virtual or mapped drives (the details of this configuration are beyond the scope of this document).

Getting QtCreator

Currently you will need to build QtCreator on your local machine. Binary downloads should be available eventually and we hope the plugins will be merged upstream.


git clone git://
cd mer-qt-creator
git checkout mer
qmake -r && make -jN && bin/qtcreator  # where N = NUM_OF_YOUR_CPUs * NUM_OF_CORES + 1 


  • use qmake-qt4 instead of qmake in the command above
  • if you want Designer make sure the package qt-devel-private is installed.

Using QtCreator

There should be a Mer button on the left toolbar; if this is not present then you will need to either enable the Mer plugin (Help -> plugins) or ensure you have the correct QtCreator installed.

Add a target

In the SDK Control Center (http://localhost:8080) go to Targets and add a new target.

For Nemo:

  • select Mer-SB2-armv7hl as the toolchain
  • select nemo_n9_min as the target name
  • select as the rootfs url

Then 'add'

This will take a while but the progress will be shown at the bottom of the screen.

Once this is installed go to : Tools -> options -> Mer -> Targets and add the target. It should appear as a subdirectory of /srv/mer/targets/

The process takes a few seconds, connects to the VM and checks the compiler etc. It then says "Successfully added target".

Now you have a Mer Kit.

VM is not registered

If you get "VM is not registered" when testing connection to Mer SDK VM, shutdown VM, close VirtualBox manager and move MerSDK entry to the top in


     <MachineEntry uuid="{looooong-uuid-here}" src="/path-to/VirtualBox VMs/MerSDK/MerSDK.vbox"/>

make it look:

     <MachineEntry uuid="{looooong-uuid-here}" src="/path-to/VirtualBox VMs/MerSDK/MerSDK.vbox"/>

Fix is on its way (as of 7/12/2012)

No SDK Control Center

If you press "upgrade" in SDK Control Center, after reboot it will not start anymore (as of 3/12/2012), to fix (in VM):

[root@localhost ~]# ln -s /usr/lib/systemd/user/sdk-webapp.service /etc/systemd/system/

Fix is on its way (as of 7/12/2012)

Adding a Device

Go to Tools -> Options -> Devices and 'Add' then pick a 'Generic Linux Device'

Follow the wizard to make a device

Check the Kit

Go to Tools -> Options -> Build & Run

You should see several tabs; the Qt Versions and Compilers should have the values filled in for your Mer target.

In the Kits tab there will be a new Kit for your target; select that. You can add a device here for deployment if you like.

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