6.3 Introduction to Containers

Containers allow you to package an application with all its libraries. They are lighter than Virtual Machines (VMs) because they share the host Kernel.

Docker vs Podman

Docker: The industry standard. Uses a daemon (background service).
Podman: Native to RHEL/Rocky. daemonless (runs as user). Commands are mostly compatible (alias docker=podman).

Basic Commands

# 1. Pull an image (download from registry)
docker pull nginx

# 2. Run a container
# -d: Detached (background)
# -p: Port mapping (Host:Container)
docker run -d -p 8080:80 nginx

# 3. List running containers
docker ps

# 4. Stop
docker stop <container_id>

Verify by visiting http://localhost:8080 in your browser.