Understanding container instance & Kubernetes services

After reading multiple blogs found good explanation on Microsoft blogs only

VMs have many benefits. These include the ability to run different operating systems on the same server, more efficient and cost-effective utilisation of physical resources and faster server provisioning. On the flip side, each VM contains an OS image, libraries, applications and more and therefore can become quite large.

A container virtualises the underlying OS and causes the containerised app to perceive that it has the OS — including CPU, memory, file storage and network connections — all to itself. Because the differences in underlying OS and infrastructure are abstracted, as long as the base image is consistent, the container can be deployed and run anywhere. For developers, this is incredibly attractive.

Since containers share the host OS, they do not need to boot an OS or load libraries. This enables containers to be much more efficient and lightweight. Containerised applications can start in seconds and many more instances of the application can fit onto the machine as compared to a VM scenario. The shared OS approach has the added benefit of reduced overhead when it comes to maintenance, such as patching and updates.

Though containers are portable, they are constrained to the operating system they are defined for. For example, a container for Linux cannot run on Windows and vice