Virtual Machines (VMs)
A Virtual Machine (VM) is an emulation of a
complete computer system. A single physical server
can host multiple VMs, each running its own copy of
an operating system (OS), dedicated memory, and
hardware resources.
The VM Advantage
VMs are great for running different OSs on one
machine (e.g., Windows and Linux side-by-side) or
for running older, specialized software. They
provide total isolation, acting like
completely separate computers.
The VM Overhead
Because each VM includes a full copy of the OS and a
virtual hardware layer, they consume significant
disk space, memory, and startup time. This led to
the rise of a more lightweight technology:
containers.
Containerization (Docker)
Containers, popularized by Docker,
package an application and all its dependencies
(libraries, code, configurations) into a single,
light-weight, executable unit. Unlike VMs,
containers share the host machine's OS kernel,
making them much more efficient.
The Docker Advantage
-
Lightweight and Fast: Containers start in
seconds and require far less overhead than a VM.
-
Consistency: The application runs the
exact same way on a developer's laptop as it
does in production, eliminating dependency
conflicts.
-
Scalability: It's easy to quickly spin up
dozens or hundreds of copies of a container to
handle high traffic.
Containers are now the dominant standard for
packaging and deploying modern Backend and
microservice applications.
