Docker

• Source: https://github.com/moby/moby
• License: Apache 2.0
• Alternatives: Podman, Kubernetes, k3s

Install using the official Docker guide (NOT via Snap).

Features

• Container Runtime: Package apps with all their dependencies into portable, reproducible images
• Docker Compose: Define and run multi-container stacks with a single YAML file
• Image Layering: Shared layers between images reduce disk usage and speed up pulls
• Networking: Bridge, overlay, and host networks for flexible container communication
• Volume Mounts: Persist data outside containers and share it between services
• Resource Limits: Cap CPU, memory, and I/O per container

Network

The exist network is automatically created when running docker compose up. To create it manually:

docker network create \
  --driver overlay \
  --attachable \
  --opt encrypted \
  exist

Privileged Port Error

To allow binding to ports like 80 without root, add to /etc/sysctl.conf:

net.ipv4.ip_unprivileged_port_start=80

Apply immediately:

sudo sysctl -w net.ipv4.ip_unprivileged_port_start=80