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

# 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 webserver

Image Management

# 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:latest

Rootless Containers

Setup

# 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_map

Running Rootless

# Run as regular user (no sudo)
podman run -d --name myapp -p 8080:80 nginx