Two Approaches to Isolation
Both Virtual Machines and containers isolate applications, but they work very differently.
Architecture Comparison
Virtual Machines: Containers:
┌──────┐ ┌──────┐ ┌──────┐ ┌──────┐ ┌──────┐ ┌──────┐
│ App1 │ │ App2 │ │ App3 │ │ App1 │ │ App2 │ │ App3 │
├──────┤ ├──────┤ ├──────┤ ├──────┤ ├──────┤ ├──────┤
│ Bins │ │ Bins │ │ Bins │ │ Bins │ │ Bins │ │ Bins │
├──────┤ ├──────┤ ├──────┤ └────┬───┘ └────┬───┘ └────┬───┘
│Guest │ │Guest │ │Guest │ └──────────┼──────────┘
│ OS │ │ OS │ │ OS │ ┌──────────────┴──────────┐
├──────┴─┴──────┴─┴──────┤ │ Docker Engine │
│ Hypervisor │ ├──────────────────────────┤
├────────────────────────┤ │ Host OS │
│ Host OS │ ├──────────────────────────┤
├────────────────────────┤ │ Hardware │
│ Hardware │ └──────────────────────────┘
└────────────────────────┘
Heavy: Each VM has full OS Light: Shared kernel, tiny footprint
Key Differences
Containers are lighter and faster, but VMs provide stronger isolation. Many production systems use both — VMs for infrastructure, containers for applications.