Traditional Virtualization Architecture with Docker on VMs
Description: In traditional virtualization, multiple virtual machines (VMs) run on a physical server using a hypervisor. Each VM includes a guest OS and can run Docker containers within it.
Layers Explanation:
Physical Server: The actual hardware resources (CPU, memory, storage, etc.).
Hypervisor: A layer that creates and manages VMs, allowing multiple OS instances to run on a single physical server.
VM (Virtual Machine): An emulation of a physical computer. Each VM runs its own guest OS.
Guest OS: The operating system running inside each VM.
Docker Engine: The Docker daemon running on the guest OS, managing containers.
Containers: Lightweight and portable execution environments that include everything needed to run a piece of software, except the OS.
Docker Architecture on a Physical Server
Description: Docker containers run directly on the host OS of the physical server, without the need for a hypervisor or VMs. This provides better performance and efficiency.
Layers Explanation:
Physical Server: The actual hardware resources (CPU, memory, storage, etc.).
Host OS: The operating system running directly on the physical server.
Docker Engine: The Docker daemon running on the host OS, managing containers.
Containers: Lightweight and portable execution environments that include everything needed to run a piece of software, sharing the host OS kernel, but isolated from each other.
Comparison:
Resource Efficiency:
- Docker containers on a physical server share the host OS kernel, making them more lightweight and efficient compared to VMs which each have their own OS.
Performance:
- Containers typically have better performance compared to VMs because there's no hypervisor overhead and they utilize fewer resources since they share the host OS kernel.
Isolation:
VMs provide stronger isolation as each VM includes its own OS, which can be an advantage for certain security requirements.
Containers provide isolation at the process level, which is generally sufficient for most applications but not as strong as VM isolation.
Boot Time:
- Containers start much faster than VMs because they do not require a full OS boot.
Learning Resources for Docker:
Official Documentation:
- Docker Docs: docs.docker.com