Comment by chasd00

iirc full virtualization was expensive ( vmware ) and paravirtualization was pretty heavyweight and slow ( Xen ). I think Docker was like a user friendlier cgroups and everyone loved it. I can't remember the name but there was a "web hosting company in a box" software that relied heavily on LXC and probably was some inspiration for containerization too.

edit: came back in to add reference to LXC, it's been probably 2 decades since i've thought about that.