Virtualization

In the beginning, users time-shared CPUs and virtualization was without form and void. And IBM said “Let there be System/370”. This was in the 70’s and involved men with crew-cuts, horn-rimmed glasses and pocket protectors. And ties. Lots of ties.

At the turn of the millennium, VMWare brought this to intel server that used on average 5% of their capacity up to that point. It was expensive, but worth it.

Today, virtualization and it’s successor, containerization, have been driven to commodities and are now simply part of Windows and Linux kernels.

Specifically with containers, there is just one kernel and it keeps groups processes separate from each other. This is possible because Linux implemented kernel namespaces around 2008 - mostly work by IBM, suitably enough. The program used to work with this is named LXC and you’d use commands like sudo lxc-create --template download --name u1 --dist ubuntu --release jammy --arch amd64. Tool like LXD and Docker (originally) just run on top to provide more management.