Embedded systems often have a long product lifetime so software needs to be built with the same Yocto version over several years in a predictable way. Older versions of Yocto often have problems in running with state-of-the-art distributions.

To work around this, there are several alternatives:

• Keep a build machine with a fixed operating system. This is problematic as the machine also ages and it may suffer from hardware problems and need re-installation.
• Use a cloud machine with a fixed operating system. Not everyone has this type of infrastructure available and it usually has a price tag attached.
• Build in a virtual machine such as VMware or VirtualBox. This affects the build performance significantly.
• Use a Docker Yocto builder container. This has the advantage of providing the same isolation as the virtual machine but with a much better build performance.

We saw how to run a docker container in the Using the Toaster web interface recipe. Now we will see how to create our own Docker image to use as a Yocto builder.