1 Introduction

Toaster is a web interface to the Yocto Project’s OpenEmbedded Build System. The interface enables you to configure and run your builds. Information about builds is collected and stored in a database. You can use Toaster to configure and start builds on multiple remote build servers.

1.1 Toaster Features

Toaster allows you to configure and run builds, and it provides extensive information about the build process.

  • Configure and Run Builds: You can use the Toaster web interface to configure and start your builds. Builds started using the Toaster web interface are organized into projects. When you create a project, you are asked to select a release, or version of the build system you want to use for the project builds. As shipped, Toaster supports Yocto Project releases 1.8 and beyond. With the Toaster web interface, you can:

    • Browse layers listed in the various layer sources that are available in your project (e.g. the OpenEmbedded Layer Index at https://layers.openembedded.org/).

    • Browse images, recipes, and machines provided by those layers.

    • Import your own layers for building.

    • Add and remove layers from your configuration.

    • Set configuration variables.

    • Select a target or multiple targets to build.

    • Start your builds.

    Toaster also allows you to configure and run your builds from the command line, and switch between the command line and the web interface at any time. Builds started from the command line appear within a special Toaster project called “Command line builds”.

  • Information About the Build Process: Toaster also records extensive information about your builds. Toaster collects data for builds you start from the web interface and from the command line as long as Toaster is running.


    You must start Toaster before the build or it will not collect build data.

    With Toaster you can:

    • See what was built (recipes and packages) and what packages were installed into your final image.

    • Browse the directory structure of your image.

    • See the value of all variables in your build configuration, and which files set each value.

    • Examine error, warning, and trace messages to aid in debugging.

    • See information about the BitBake tasks executed and reused during your build, including those that used shared state.

    • See dependency relationships between recipes, packages, and tasks.

    • See performance information such as build time, task time, CPU usage, and disk I/O.

For an overview of Toaster shipped with the Yocto Project 4.1.999 Release, see the “Toaster - Yocto Project 2.2” video.

1.2 Installation Options

You can set Toaster up to run as a local instance or as a shared hosted service.

When Toaster is set up as a local instance, all the components reside on a single build host. Fundamentally, a local instance of Toaster is suited for a single user developing on a single build host.


Toaster as a hosted service is suited for multiple users developing across several build hosts. When Toaster is set up as a hosted service, its components can be spread across several machines: