Containers vs. Virtual Machines: A Beginner’s Journey

Containers: A containers is an isolated environments for running an application. A Docker container image is a lightweight, standalone, executable package of software that includes everything needed to run an application: code, runtime, system tools, system libraries and settings.

Pros of Containers:

• Lightweight: Containers share the host OS, making them much lighter and faster to start than VMs.
• Efficiency: They use fewer resources, allowing more containers to run on the same hardware compared to VMs.
• Scalability: Ideal for microservices and scaling applications quickly.

Cons of Containers:

• Shared Kernel: Since containers share the host OS kernel, they offer less isolation than VMs.
• Compatibility: Containers are limited to the OS of the host system.

Virtual Machine(VM): VM is a abstraction of machines (physical hardware). A virtual machine is a digital copy of a physical machine. You can have multiple virtual machines with their own individual operating systems running on the same host operating system.

Pros of Virtual Machines:

• Isolation: VMs offer strong isolation, as each VM runs its own OS.
• Versatility: They can run different OSes on the same physical hardware.
• Security: Enhanced security due to complete OS separation.

Cons of Virtual Machines:

• Resource Intensive: VMs are heavy, consuming significant CPU, memory, and storage resources.
• Slower Startup: VMs take longer to boot up due to their complete OS stack.

When to Use What?

• Use VMs if: You need strong isolation for security purposes, need to run multiple different OSes, or are dealing with legacy applications that require a full OS environment.
• Use Containers if: You’re developing microservices, need rapid scaling, or want to maximize resource efficiency.

Different between Containers and Virtual Machines

Containers

1. A containers is an isolated environments for running an application.
2. Allow running multiple apps in isolation.
3. More lightweight.
4. Use "OS" of the host.
5. Need less hardware resources.
6. containers does not container full-blown operating system.

Virtual Machines(VM)

1. VM is a abstraction of machines (physical hardware).
2. on same physical machine we can have two different machine, where each running completely different application and each application has exact dependencies.
3. More heavyweight
4. Slow to start (Entire apps needs to be loaded).
5. Resource intensive (Each machine takes actual hardware. resources).
6. Each VM needs a full-blown OS.