Agent skill

container-hardening

Secure Docker images and container runtime configurations. Implement non-root users, read-only filesystems, and security contexts. Use when building secure container images or hardening container deployments.

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Install this agent skill to your Project

npx add-skill https://github.com/majiayu000/claude-skill-registry/tree/main/skills/other/other/container-hardening

Metadata

Additional technical details for this skill

author
devops-skills
version
1.0

SKILL.md

Container Hardening

Secure container images and runtime configurations.

When to Use This Skill

Use this skill when:

  • Building secure container images
  • Hardening container deployments
  • Meeting container security requirements
  • Implementing defense in depth

Dockerfile Security

dockerfile
# Use minimal base image
FROM alpine:3.18

# Don't run as root
RUN addgroup -g 1001 -S appgroup && \
    adduser -u 1001 -S appuser -G appgroup

# Copy with specific ownership
COPY --chown=appuser:appgroup . /app

# Remove unnecessary packages
RUN apk del --purge build-dependencies && \
    rm -rf /var/cache/apk/*

# Use non-root user
USER appuser

# Read-only filesystem support
WORKDIR /app

Runtime Security

bash
# Run with security options
docker run -d \
  --read-only \
  --tmpfs /tmp \
  --security-opt=no-new-privileges:true \
  --cap-drop=ALL \
  --cap-add=NET_BIND_SERVICE \
  --user 1001:1001 \
  myapp:latest

Kubernetes Security Context

yaml
apiVersion: v1
kind: Pod
spec:
  securityContext:
    runAsNonRoot: true
    runAsUser: 1001
    fsGroup: 1001
  containers:
  - name: app
    securityContext:
      allowPrivilegeEscalation: false
      readOnlyRootFilesystem: true
      capabilities:
        drop: ["ALL"]

Image Scanning

bash
# Scan with Trivy
trivy image --severity HIGH,CRITICAL myapp:latest

# Use distroless images
FROM gcr.io/distroless/static-debian11

Best Practices

  • Use minimal base images
  • Run as non-root user
  • Enable read-only filesystem
  • Drop all capabilities
  • Scan images regularly
  • Sign and verify images
  • Use secrets management

Related Skills

  • container-scanning - Vulnerability scanning
  • kubernetes-hardening - K8s security

Expand your agent's capabilities with these related and highly-rated skills.

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