Docker Vs Virtual Machine (VM)
Docker containers and Virtual Machines (VMs) both let you run applications in isolated environments, but they do it in fundamentally different ways. The main difference is that Docker virtualizes the operating system, while a VM virtualizes the physical hardware.
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Virtual Machine (VM)
A Virtual Machine is an entire computer emulated in software. A piece of software called a hypervisor (like VMware or VirtualBox) runs on a host machine and creates a complete virtual copy of the underlying hardware.
- Heavyweight š: Each VM needs to run its own full guest operating system (e.g., a full installation of Windows or Linux), complete with its own kernel, libraries, and dependencies.
- Full Isolation: Because everything is separate, VMs provide very strong security and isolation from the host and other VMs.
- Slower & Bulkier: Starting a VM is like booting up a real computer, which can take several minutes. They consume a significant amount of RAM and disk space because of the full OS running inside.
Docker Container
Docker uses a different approach called containerization. Instead of virtualizing the hardware, Docker virtualizes the operating system.
- Lightweight feather: Containers share the host machineās operating system kernel. They donāt need a full guest OS. They just package the application code, its libraries, and dependencies into a single, isolated unit called a container.
- Process-Level Isolation: Docker provides isolation at the process level, which is very secure for most applications but less isolated than a full VM.
- Fast & Efficient: Containers can start almost instantly because thereās no OS to boot. They use far less memory and disk space, allowing you to run many more containers on a single host compared to VMs.