there is something i want to explore when i have containers ready to go. the idea is to run qemu in user-mode, where it does the emulation of other architectures on a per-process basis, including support for threads (mapped to host threads). the full idea is to create a container with the image of another architecture and run init in the container under qemu user-mode. each child forked and/or execed from there is running under qemu user-mode. thus, the entire container can be running in isolated emulation. if that works well, the many needs to run virtual machines for emulated architectures to do things like compiling, building, linking, etc., can operate more like a virtual machines but with the performance boost of not having two operating system layers.
has anyone here done anything like this?