How to use
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npx skills add https://github.com/bagelhole/devops-security-agent-skills --skill podmanBefore you start
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Original skill document
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Podman
Run and manage containers without a daemon using Podman's rootless container engine.
When to Use This Skill
Use this skill when:
- Running containers without root privileges
- Managing containers on systems without Docker
- Creating pod-based container groups
- Using systemd for container management
- Working in security-conscious environments
Prerequisites
- Podman installed (4.x+)
- For rootless: user namespaces enabled
- Basic container concepts understanding
Key Differences from Docker
| Feature | Docker | Podman |
|---|---|---|
| Architecture | Client-daemon | Daemonless |
| Root required | Default | Optional (rootless) |
| Pod support | No | Yes (Kubernetes-style) |
| Systemd integration | Limited | Native |
| Socket | docker.sock | podman.sock (optional) |
Basic Commands
Container Operations
bash
# Run container (identical to Docker)
podman run -d --name webserver -p 8080:80 nginx
# List containers
podman ps -a
# Stop and remove
podman stop webserver
podman rm webserver
# Execute command
podman exec -it webserver /bin/sh
# View logs
podman logs -f webserverImage Management
bash
# Pull image
podman pull docker.io/library/nginx:latest
# List images
podman images
# Build image
podman build -t myapp:latest .
# Push to registry
podman push myapp:latest registry.example.com/myapp:latest
# Remove image
podman rmi nginx:latestRootless Containers
Setup
bash
# Check user namespace support
cat /proc/sys/user/max_user_namespaces
# Enable if needed (as root)
echo "user.max_user_namespaces=28633" | sudo tee /etc/sysctl.d/userns.conf
sudo sysctl -p /etc/sysctl.d/userns.conf
# Configure subuid/subgid for user
sudo usermod --add-subuids 100000-165535 --add-subgids 100000-165535 $USER
# Verify
podman unshare cat /proc/self/uid_mapRunning Rootless
bash
# Run as regular user (no sudo)
podman run -d --name myapp -p 8080:80 nginx
# Check user namespace mapping
podman unshare id
# Verify non-root
podman top myapp userPort Considerations
bash
# Rootless cannot bind to ports < 1024 by default
# Use ports >= 1024
podman run -d -p 8080:80 nginx
# Or enable unprivileged ports (as root)
echo "net.ipv4.ip_unprivileged_port_start=80" | sudo tee /etc/sysctl.d/ports.conf
sudo sysctl -p /etc/sysctl.d/ports.confPods
Creating Pods
bash
# Create pod
podman pod create --name mypod -p 8080:80 -p 5432:5432
# Add containers to pod
podman run -d --pod mypod --name web nginx
podman run -d --pod mypod --name db postgres:15
# List pods
podman pod ps
# Containers share network namespace
podman exec web curl localhost:5432Pod Management
bash
# Start/stop pod (affects all containers)
podman pod start mypod
podman pod stop mypod
# Remove pod and containers
podman pod rm -f mypod
# View pod details
podman pod inspect mypod
# Generate Kubernetes YAML from pod
podman generate kube mypod > mypod.yamlSystemd Integration
Generate Systemd Unit
bash
# Generate unit file for container
podman generate systemd --new --name myapp > ~/.config/systemd/user/container-myapp.service
# For pod
podman generate systemd --new --name mypod --files
# Reload systemd
systemctl --user daemon-reload
# Enable and start
systemctl --user enable --now container-myapp.serviceQuadlet (Podman 4.4+)
ini
# ~/.config/containers/systemd/webapp.container
[Container]
Image=docker.io/library/nginx:latest
PublishPort=8080:80
Volume=webapp-data:/usr/share/nginx/html
[Service]
Restart=always
[Install]
WantedBy=default.targetbash
# Reload to generate service
systemctl --user daemon-reload
# Start the service
systemctl --user start webappCompose Compatibility
Using Podman Compose
bash
# Install podman-compose
pip install podman-compose
# Run compose file
podman-compose up -d
# Or use Docker Compose with Podman socket
systemctl --user enable --now podman.socket
export DOCKER_HOST=unix:///run/user/$UID/podman/podman.sock
docker-compose up -dNative Podman Kube
bash
# Play Kubernetes YAML
podman kube play deployment.yaml
# Stop and remove
podman kube down deployment.yamlNetworking
Network Management
bash
# Create network
podman network create mynetwork
# Run on network
podman run -d --network mynetwork --name app myapp
# Connect container to network
podman network connect mynetwork existing-container
# List networks
podman network ls
# Inspect network
podman network inspect mynetworkDNS Resolution
bash
# Containers on same network can resolve by name
podman run -d --network mynetwork --name db postgres:15
podman run -d --network mynetwork --name app \
-e DATABASE_HOST=db myappStorage
Volume Management
bash
# Create volume
podman volume create mydata
# Use volume
podman run -d -v mydata:/data myapp
# List volumes
podman volume ls
# Inspect volume
podman volume inspect mydata
# Rootless volumes location
ls ~/.local/share/containers/storage/volumes/Bind Mounts
bash
# Bind mount with SELinux label
podman run -v ./data:/app/data:Z myapp
# Z = private label (single container)
# z = shared label (multiple containers)Registry Configuration
Configure Registries
bash
# Edit registries.conf
# ~/.config/containers/registries.conftoml
unqualified-search-registries = ["docker.io", "quay.io"]
[[registry]]
prefix = "docker.io"
location = "docker.io"
[[registry.mirror]]
location = "mirror.gcr.io"Authentication
bash
# Login to registry
podman login docker.io
# Login to private registry
podman login registry.example.com
# Credentials stored in
# ~/.config/containers/auth.jsonBuilding Images
Buildah Integration
bash
# Podman uses Buildah for builds
podman build -t myapp:latest .
# Build with specific format
podman build --format docker -t myapp .
# Multi-stage build
podman build --target production -t myapp:prod .Buildah Commands
bash
# Create container from scratch
buildah from scratch
buildah copy working-container ./app /app
buildah config --entrypoint '["/app/main"]' working-container
buildah commit working-container myapp:minimalCommon Issues
Issue: Permission Denied
Problem: Cannot access files in mounted volumes Solution: Use :Z or :z suffix for SELinux, or check ownership
Issue: Cannot Connect to Container
Problem: Port not accessible in rootless mode Solution: Use ports >= 1024 or configure unprivileged port start
Issue: Slow Image Pulls
Problem: Images download slowly Solution: Configure registry mirrors in registries.conf
Issue: Systemd Service Fails
Problem: Container doesn't start via systemd Solution: Enable lingering: loginctl enable-linger $USER
Best Practices
- Use rootless mode for enhanced security
- Leverage pods for related containers
- Generate systemd units for production
- Use Quadlet for declarative container services
- Configure SELinux labels for bind mounts
- Enable user lingering for persistent services
- Use podman auto-update for automatic updates
- Alias
dockertopodmanfor compatibility
Related Skills
- docker-management - Docker fundamentals
- kubernetes-ops - K8s orchestration
- container-hardening - Security
