Chapter 8. Images

The OpenEmbedded build process supports several types of images to satisfy different needs. When you issue the bitbake command you provide a “top-level” recipe that essentially begins the build for the type of image you want.

Note

Building an image without GNU General Public License Version 3 (GPLv3) components is only supported for minimal and base images. Furthermore, if you are going to build an image using non-GPLv3 components, you must make the following changes in the local.conf file before using the BitBake command to build the minimal or base image:

     1. Comment out the EXTRA_IMAGE_FEATURES line
     2. Set INCOMPATIBLE_LICENSE = "GPLv3"

From within the poky Git repository, use the following command to list the supported images:

     $ ls meta*/recipes*/images/*.bb

These recipes reside in the meta/recipes-core/images, meta/recipes-extended/images, meta/recipes-graphics/images, and meta/recipes-sato/images directories within the source directory. Although the recipe names are somewhat explanatory, here is a list that describes them:

core-image-base: A console-only image that fully supports the target device hardware.
core-image-minimal: A small image just capable of allowing a device to boot.
core-image-minimal-dev: A core-image-minimal image suitable for development work using the host. The image includes headers and libraries you can use in a host development environment.
core-image-minimal-initramfs: A core-image-minimal image that has the Minimal RAM-based Initial Root Filesystem (initramfs) as part of the kernel, which allows the system to find the first “init” program more efficiently.
core-image-minimal-mtdutils: A core-image-minimal image that has support for the Minimal MTD Utilities, which let the user interact with the MTD subsystem in the kernel to perform operations on flash devices.
core-image-x11: A very basic X11 image with a terminal.
core-image-basic: A console-only image with more full-featured Linux system functionality installed.
core-image-lsb: An image that conforms to the Linux Standard Base (LSB) specification.
core-image-lsb-dev: A core-image-lsb image that is suitable for development work using the host. The image includes headers and libraries you can use in a host development environment.
core-image-lsb-sdk: A core-image-lsb that includes everything in meta-toolchain but also includes development headers and libraries to form a complete standalone SDK. This image is suitable for development using the target.
core-image-clutter: An image with support for the Open GL-based toolkit Clutter, which enables development of rich and animated graphical user interfaces.
core-image-sato: An image with Sato support, a mobile environment and visual style that works well with mobile devices. The image supports X11 with a Sato theme and applications such as a terminal, editor, file manager, media player, and so forth.
core-image-sato-dev: A core-image-sato image suitable for development using the host. The image includes libraries needed to build applications on the device itself, testing and profiling tools, and debug symbols. This image was formerly core-image-sdk.
core-image-sato-sdk: A core-image-sato image that includes everything in meta-toolchain. The image also includes development headers and libraries to form a complete standalone SDK and is suitable for development using the target.
core-image-rt: A core-image-minimal image plus a real-time test suite and tools appropriate for real-time use.
core-image-rt-sdk: A core-image-rt image that includes everything in meta-toolchain. The image also includes development headers and libraries to form a complete stand-alone SDK and is suitable for development using the target.
core-image-gtk-directfb: An image that uses gtk+ over directfb instead of X11. In order to build, this image requires specific distro configuration that enables gtk over directfb.
build-appliance-image: An image you can boot and run using either the VMware Player or VMware Workstation. For more information on this image, see the Build Appliance page on the Yocto Project website.

Tip

From the Yocto Project release 1.1 onwards, -live and -directdisk images have been replaced by a "live" option in IMAGE_FSTYPES that will work with any image to produce an image file that can be copied directly to a CD or USB device and run as is. To build a live image, simply add "live" to IMAGE_FSTYPES within the local.conf file or wherever appropriate and then build the desired image as normal.