Docker containers vs Virtual machines

 Docker containers vs Virtual machines(VMs)

Docker containers and virtual machines both are ways to deploy applications inside the environments that are isolated from underlying hardware. The main difference is level of isolation. The main key thing is that docker container uses the same kernel as the host system.

In contrast with virtual machines, everything running inside the VM is independent of host system. The virtual machine starts a process call Virtual Machine Monitor(VMM) to run the specific VM and host system allocates some hardware resources to VM. VM uses a dedicated kernel to run the OS.

Virtualization

Software called a hypervisor separates resources from their physical machines so they can be partitioned and dedicated to VMs. When a user issues a VM instruction that requires additional resources from the physical environment, the hypervisor relays the request to the physical system and caches the changes. VMs look and act like physical servers, which can multiply the drawbacks of application dependencies and large OS footprints—a footprint that's mostly not needed to run a single app or microservice.

Containers

Containers hold a microservice or app and everything it needs to run. Everything within a container is preserved on something called an image—a code-based file that includes all libraries and dependencies. These files can be thought of as a Linux distribution installation because the image comes with RPM packages, and configuration files. Because containers are so small, there are usually hundreds of them loosely coupled together—which is why container orchestration platforms are used to provision and manage them.

Conclusion

Both containers and VMs are great technologies. When you want lightweight and fast runtime performance, agility, flexibility(OS less kernel) then go for docker. Despite VMs consumes lot of memory compare to containers but they are more isolated than containers.

Containers differ from virtual machines in one key area: they’re service-focused, whereas VMs are system-focused. In a nutshell, containers are dedicated to serving a function instead of providing a foundation. Containers virtualize an operating system (OS) and it is capable of running multiple workloads on a single OS instance while VMs virtualize the hardware to run multiple OS instances.

Note: If you think this helped you and you want to learn more stuff on devops, then I would recommend joining the Kodecloud devops course and go for the complete certification path by clicking this link