What is the difference between containers and virtual machines?

Question

Accepted Answer

**Containers** — lightweight, shared kernel. **VMs** — full OS, isolated.

**Containers:**
- Share host OS kernel.
- Lightweight.
- Fast startup.
- Less isolation.

```
Containers:
[App A] [App B] [App C]
  [Container Runtime (Docker)]
  [Host OS Kernel]
  [Hardware]
(Shared kernel)
```

**Virtual Machines:**
- Full OS per VM.
- Heavy.
- Slow startup.
- Strong isolation.

```
VMs:
[App A] [App B] [App C]
  [OS]   [OS]   [OS]
  [Hypervisor]
  [Hardware]
(Each has own OS)
```

**Key differences:**
- **Containers** — shared kernel.
- **VMs** — full OS.
- **Containers** — lightweight.
- **VMs** — heavy.

Systems Analyst: What is the difference between containers and virtual machines?