Build an Automotive Grade Linux image
HERE OTA Connect lets you easily manage OTA updates to embedded devices running custom-built Yocto images. It works great with Automotive Grade Linux, so building an AGL image is one easy way to get started. If your planned project is automotive, AGL is a great choice to start out with. Out of the box, HERE OTA Connect works with AGL builds for QEMU and Raspberry Pi Model 3.
You’ll need a build machine with the following:
On a Debian-based system, you should be able to install all the required packages with the following command:
sudo apt install gawk wget git diffstat unzip texinfo gcc-multilib build-essential chrpath socat cpio python python3 python3-pip python3-pexpect python-dev xz-utils debianutils iputils-ping cpu-checker default-jre parted
Many/most distros that aren’t on the officially supported list will still work just fine—feel free to give it a try with whatever you’re running.
100GB+ of free disk space
6GB+ of RAM
Download the latest version directly from Google, or
install it from your distro’s packages if available (
sudo apt install repo)
|It’s possible use a virtual machine running Linux as your build machine. However, we don’t recommend it. It will be slower, and you’re more likely to run into difficult-to-troubleshoot issues. If you do want to use a VM despite this warning, though, make sure the VM has enough resources allocated to it. Along with the disk space and memory requirements above, we suggest allocating at least 4-6 CPU cores to the VM to speed up building.|
Also, make sure that you’ve generated your provisioning credentials first.
First, use the manifest file for AGL’s Happy Halibut release to download the required repositories:
mkdir myproject cd myproject repo init -b halibut -m halibut_8.0.2.xml -u https://gerrit.automotivelinux.org/gerrit/AGL/AGL-repo repo sync
Now you can run the following script to get the environment set up:
source meta-agl/scripts/aglsetup.sh -m <target-architecture> agl-sota (1)
As described in the AGL wiki, you will need to edit your
bblayers.conf to replace
By default, AGL for QEMU boots into an initrd before loading the root filesystem, but as of thud, meta-updater by default uses an initramfs. You will need to force the build to use an initramfs by adding this to your
AGL_DEFAULT_INITRAMFS_FSTYPES = "cpio.gz"
The environment setup script will have created a build directory and placed you in it. It also generates a configuration file, located at
conf/local.conf. This file is where we’ll make our modifications to the base config.
To connect with your HERE OTA Connect account, you’ll need the provisioning credentials bundle you downloaded earlier. Add the following line to your local.conf to supply those credentials to the build:
SOTA_PACKED_CREDENTIALS = "/path/to/your/credentials.zip"
Set image name
When you build a filesystem image, it gets automatically uploaded to OTA Connect. By default, the image will be named
<machine-name>-ota, and you’ll see the various versions of the image under that name. You can also choose to set your own name as follows:
OSTREE_BRANCHNAME = "my-super-great-project"
Persistent Yocto shared state cache and download directory
Yocto caches its build artefacts to speed up future builds. By default, these are stored under the build directory of the current project. However, if you’re planning to build several different projects that have some shared base files, you might want them to share their cache directories, both to save space and speed up your builds. You can do that as follows:
SSTATE_DIR = "/path/to/your/shared-sstate" DL_DIR = "/path/to/your/shared-download"
Add extra packages
There are quite a lot of packages available to install that aren’t installed by default. You can add extra packages to your image with IMAGE_INSTALL_append; for example, this will install vim:
IMAGE_INSTALL_append = " vim " (1)
|1||Note the spaces before and after the package name. This option dumbly appends a string to an install list, so we wrap it in spaces to make sure we don’t alter the list in unexpected ways.|
You can get a list of all the available packages in the layers you have configured with
Now you’re ready to build your image.
This step will take a while. Building everything from scratch, it will likely take several hours.
If the build fails due a problem with the tar recipe, try this command:
bitbake -c clean tar-native
You can then retry bitbaking your image.
You can now flash the image onto an SD card using the same method as described for a regular Raspberry Pi build. However, the exact image you’ll need will vary depending on the architecture you’re building for, but it will be located in the
/tmp/deploy/images directory under your build directory. You can also use Etcher to write the image, or follow the normal flashing procedure for your device if applicable.
You can also write the image using
You can now run the image in QEMU using the same method as described for a regular QEMU build. However, the exact image you’ll need will vary depending on the architecture you’re building for, but it will be located in the
/tmp/deploy/images directory under your build directory.
Once you’ve built your first image, try adding some new software and push your update to the OTA Connect server.
agl-image-minimaltarget for Raspberry Pi 3 creates an image at
agl-image-minimaltarget for QEMU creates an image at