# Container

> Container technology reference — Docker, OCI images, namespaces, cgroups, and container runtime internals. Use when understanding container isolation, image layering, or debugging container issues.

- Skill: `bytesagain/container` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add bytesagain/container`
- Raw SKILL.md: https://api.skillmd.com/api/skills/bytesagain/container/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: DevOps & Infra
- Author: bytesagain (https://skillmd.com/u/bytesagain)
- Updated: 2026-09-09
- Page: https://skillmd.com/skills/bytesagain/container

---


# Container — Container Technology Reference

Quick-reference skill for container internals, image formats, and runtime mechanics.

## When to Use

- Understanding how containers provide process isolation
- Debugging container networking, storage, or resource issues
- Learning OCI image specification and layer mechanics
- Comparing container runtimes (runc, containerd, CRI-O)
- Optimizing Dockerfile builds for smaller, faster images

## Commands

### `intro`

```bash
scripts/script.sh intro
```

Overview of container technology — history, OCI standards, and architecture.

### `namespaces`

```bash
scripts/script.sh namespaces
```

Linux namespaces — the isolation mechanism behind containers.

### `cgroups`

```bash
scripts/script.sh cgroups
```

Control groups — resource limiting for CPU, memory, I/O, and PIDs.

### `images`

```bash
scripts/script.sh images
```

OCI image format — layers, manifests, and union filesystems.

### `networking`

```bash
scripts/script.sh networking
```

Container networking — bridge, host, overlay, and CNI plugins.

### `storage`

```bash
scripts/script.sh storage
```

Container storage — volumes, bind mounts, and storage drivers.

### `runtimes`

```bash
scripts/script.sh runtimes
```

Container runtimes compared: runc, containerd, CRI-O, Kata, gVisor.

### `security`

```bash
scripts/script.sh security
```

Container security — capabilities, seccomp, AppArmor, rootless mode.

### `help`

```bash
scripts/script.sh help
```

### `version`

```bash
scripts/script.sh version
```

## Configuration

| Variable | Description |
|----------|-------------|
| `CONTAINER_DIR` | Data directory (default: ~/.container/) |

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