Operations, Observability, and Maintenance

Once your containers are running, the work shifts to keeping them healthy, clean, and up to date. This module covers the "Day 2" tasks that prevent your Docker host from degrading over time.

The Maintenance Cycle

flowchart LR
    A["Monitor<br/>(logs, disk, health)"] --> B["Detect<br/>(alerts, thresholds)"]
    B --> C["Act<br/>(prune, update, fix)"]
    C --> D["Verify<br/>(health checks, df)"]
    D --> A

    style A fill:#e3f2fd,stroke:#1565c0
    style B fill:#fff3e0,stroke:#ef6c00
    style C fill:#e8f5e9,stroke:#2e7d32
    style D fill:#f3e5f5,stroke:#7b1fa2

What You Will Learn

Lesson	What It Covers
Logging and Log Drivers	Configure log rotation to prevent disk fills
Disk Usage and Cleanup	Monitor Docker disk usage and reclaim space safely
Updating Containers	Strategies for upgrading applications with minimal downtime

Maintenance Quick Reference

Frequency	Task	Command
Daily	Check container health	docker compose ps
Weekly	Check disk usage	docker system df
Monthly	Prune unused objects	docker system prune
As needed	Update container images	docker compose pull && docker compose up -d
As needed	Upgrade Docker Engine	apt-get update && apt-get upgrade docker-ce

Prerequisites

• Understand Docker Compose workflows (Module 7)