Docker is not intended to replace VMs. It provides lightweight isolation for processes within a host but shares a kernel between processes, and some handy tooli

Docker is not intended to replace VMs. It provides lightweight isolation for processes within a host but shares a kernel between processes, and some handy tooling for building images that works well with version control. (Building a CentOS based image is under a dozen LOC in Docker, and a few hundred LOC in Packer+Kickstart.) Kata Containers (https://katacontainers.io https://katacontainers.io) is more along the lines of a "VM replacement", although it is doing so using VMs.