The Buildroot Distribution

Buildroot is a minimal Linux distribution intended for embedded systems (you can find more information on their website. The advantage of buildroot is that it requires little disk space and boots quickly. It is also less complex which can make some workloads easier to build and debug. However, Buildroot does not have a convential package management system, instead you must configure any packages or options you need at compile time. To do this, you will need to modify the distro options in your workload.



A list of buildroot configuration fragments. Buildroot uses the kconfig system from Linux for configuration and the behavior of kernel fragments is the same as in Linux.

Some Buildroot options require a path to external files (e.g. a custom busybox configuration). You should not use relative paths for these as the buildroot source directory may move in future versions of FireMarshal. Instead, FireMarshal provides the absolute path to your workload directory via an environment variable named $(WORKLOAD_NAME_PATH) where “WORKLOAD_NAME” is the name of your workload with any ‘-’ characters replaced with underscore. This variable may be used in your buildroot configuration file. For example, suppose we have a workload named foo-bar that wishes to provide a custom busybox configuration (placed in foo-bar’s workdir). It would include a buildroot configuration fragment with the following option:



Because the custom busybox configuration is referenced only by the buildroot configuration, FireMarshal cannot detect changes to that file. You will have to explicitly clean and rebuild the workload to pick up changes to dependencies like that.


In addition to the provided $(WORKLOAD_NAME_PATH) variable, users may provide aditional environment variables to customize their buildroot configuration or build. These variables will be available for use in the workload’s buildroot configuration and will be passed when invoking make on buildroot. Variables are provided as a dictionary of { 'VARIABLE_NAME' : 'value' }. You may include variable substitutions from the local environment or the special $(WORKLOAD_NAME_PATH) variable. Continuing with the example foo-bar above, let’s assume we’ve defined $ENV_VARIABLE before invoking FireMarshal. We can then include the following in our workload: