Well Rancher products normally use docker-machine in the examples, thus they must be developed in Macs 
No idea about the othersā¦
Here it his an interesting explanation about the SmartOS virtualization at the Operating System level:
https://wiki.smartos.org/smartos-virtualization/
Joyent SmartMachines are Based on Solaris ZonesĀ¶
Which gives us:
- CPU scheduling
- network virtualization
- security
Zones virtualization was added to Solaris 10 in 2005.