# 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.

This release of Toaster does allow you to configure and initiate builds. However, you cannot use Toaster to customize image recipes, which still must either be done by hand or through Hob. As Toaster matures, it eventually will equal and surpass Hob functionality, at which time Hob will be deprecated.

For more information on Hob, see the "Image Development Using Hob" section in the Yocto Project Development Manual.

## Toaster Operational Modes

You can use Toaster in Analysis Mode or Build Mode:

- Analysis Mode: In Analysis Mode, you can record builds and statistics. In this Mode, you directly access the `bitbake` command, which you then use to build images.

  Analysis Mode requires you to have first started Toaster and then to initiate your build using the `bitbake` command from the shell. Toaster must be started before the build or it will not collect build data.

  Toaster has the following capabilities in Analysis Mode:

  - 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.

- Build Mode: In Build Mode, Toaster handles the build configuration, scheduling and execution. In this mode, all your interaction with the build system happens through the web interface. You do not have direct access to the `bitbake` command.

  Using this mode, you configure and start your builds within Toaster's GUI. Each project can be configured for a specific version of the build system. As shipped, Toaster supports Yocto Project Releases 1.7 and beyond.

  Toaster has all the same capabilities in Build Mode as it does in Analysis Mode plus the following:

  - Browse layers listed in the various layer sources that are available in your project (e.g. the OpenEmbedded Metadata Index at ).

  - 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.

## Installation Options

You can set Toaster up to run as a local instance or as a shared hosted service. Regardless of how you set up Toaster, both Analysis and Build Modes are available.

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: