How do I install the Docker skill?

Run npx skillmds@latest add ruc-nlpir/docker in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Docker safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Docker?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Docker free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Docker?

ruc-nlpir (@ruc-nlpir) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Docker by ruc-nlpir — Agent Skill

Name: Docker
Author: ruc-nlpir

Docker

Docker containers, images, Compose stacks, networking, volumes, debugging, production hardening, and the commands that keep real environments stable. Use when (1) the task touches Docker, Dockerfiles, images, containers, or Compose; (2) build reliability, runtime behavior, logs, ports, volumes, or security matter; (3) the agent needs Docker guidance and should apply it by default.

ruc-nlpir 528eac6 2.6 KB Updated Sep 17, 2026

File contents

When to Use

Use when the task involves Docker, Dockerfiles, container builds, Compose, image publishing, networking, volumes, logs, debugging, or production container operations. This skill is stateless and should be applied directly whenever Docker work appears.

Core Rules

1. Pin Image Versions

python:3.11.5-slim not python:latest
Today's latest differs from tomorrow's — breaks immutable builds

2. Combine RUN Commands

apt-get update && apt-get install -y pkg in ONE layer
Separate layers = stale package cache weeks later

3. Non-Root by Default

Add USER nonroot in Dockerfile
Running as root fails security scans and platform policies

4. Set Resource Limits

-m 512m on every container
OOM killer strikes without warning otherwise

5. Configure Log Rotation

Default json-file driver has no size limit
One chatty container fills disk and crashes host

Image Traps

Multi-stage builds: forgotten --from=builder copies from wrong stage silently
COPY before RUN invalidates cache on every file change — copy requirements first, install, then copy code
ADD extracts archives automatically — use COPY unless you need extraction
Build args visible in image history — never use for secrets

Runtime Traps

localhost inside container is container's localhost — bind to 0.0.0.0
Port already in use: previous container still stopping — wait or force remove
Exit code 137 = OOM killed, 139 = segfault — check with docker inspect --format='{{.State.ExitCode}}'
No shell in distroless images — docker cp files out or use debug sidecar

Secrets and Security

ENV and COPY bake secrets into layer history permanently — use secrets mount or runtime env
--privileged disables all security — almost never needed, find specific capability instead
Images from unknown registries may be malicious — verify sources
Build args visible in image history — don't use for secrets

Related Skills

Install with clawhub install <slug> if user confirms:

devops — deployment pipelines
linux — host system management
server — server administration

Feedback

If useful: clawhub star docker
Stay updated: clawhub sync

---name: dockerdescription: Docker containers, images, Compose stacks, networking, volumes, debugging, production hardening, and the commands that keep real environments stable. Use when (1) the task touches Docker, Dockerfiles, images, containers, or Compose; (2) build reliability, runtime behavior, logs, ports, volumes, or security matter; (3) the agent needs Docker guidance and should apply it by default.---## When to UseUse when the task involves Docker, Dockerfiles, container builds, Compose, image publishing, networking, volumes, logs, debugging, or production container operations. This skill is stateless and should be applied directly whenever Docker work appears.## Core Rules### 1. Pin Image Versions- `python:3.11.5-slim` not `python:latest`- Today's latest differs from tomorrow's — breaks immutable builds### 2. Combine RUN Commands- `apt-get update && apt-get install -y pkg` in ONE layer- Separate layers = stale package cache weeks later### 3. Non-Root by Default- Add `USER nonroot` in Dockerfile- Running as root fails security scans and platform policies### 4. Set Resource Limits- `-m 512m` on every container- OOM killer strikes without warning otherwise### 5. Configure Log Rotation- Default json-file driver has no size limit- One chatty container fills disk and crashes host## Image Traps- Multi-stage builds: forgotten `--from=builder` copies from wrong stage silently- COPY before RUN invalidates cache on every file change — copy requirements first, install, then copy code- `ADD` extracts archives automatically — use `COPY` unless you need extraction- Build args visible in image history — never use for secrets## Runtime Traps- `localhost` inside container is container's localhost — bind to `0.0.0.0`- Port already in use: previous container still stopping — wait or force remove- Exit code 137 = OOM killed, 139 = segfault — check with `docker inspect --format='{{.State.ExitCode}}'`- No shell in distroless images — `docker cp` files out or use debug sidecar## Secrets and Security- ENV and COPY bake secrets into layer history permanently — use secrets mount or runtime env- `--privileged` disables all security — almost never needed, find specific capability instead- Images from unknown registries may be malicious — verify sources- Build args visible in image history — don't use for secrets## Related SkillsInstall with `clawhub install <slug>` if user confirms:- `devops` — deployment pipelines- `linux` — host system management- `server` — server administration## Feedback- If useful: `clawhub star docker`- Stay updated: `clawhub sync`

Frequently asked questions