...
The launch_cvd command rus two commands assemble_cvd and run_cvd in its child processes. If both commands work as expected, the Android can launch successfully on Cuttlefish machine. The assemble_cvd command generates root file system images with overlay / qcow2 format, then the run_cvd command invokes the virtual machine manager (either Crosvm or QEMU) to boot the virtual machine with the generated images. The diagram below shows the Cuttlefish flow.
...
Using assemble_cvd
Let’s we assume we work on TRS and want to run Android Automotive OS on Xen virtual machine, in this case, we cannot directly use launch_cvd command for launching Xen virtual machine. Therefore, we need to use assumble_cvd command to help us to generate file system images, and afterwards we can execute QEMU command to launch Xen virtual machine. This is why we need to understand how to use assumble_cvd command.
...