Server Management

> Server management principles for production operations.

> Learn to THINK, not memorize commands.

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1. Process Management Principles

Tool Selection

| Scenario | Tool |

|----------|------|

| Node.js app | PM2 (clustering, reload) |

| Any app | systemd (Linux native) |

| Containers | Docker/Podman |

| Orchestration | Kubernetes, Docker Swarm |

Process Management Goals

| Goal | What It Means |

|------|---------------|

| Restart on crash | Auto-recovery |

| Zero-downtime reload | No service interruption |

| Clustering | Use all CPU cores |

| Persistence | Survive server reboot |

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2. Monitoring Principles

What to Monitor

| Category | Key Metrics |

|----------|-------------|

| Availability | Uptime, health checks |

| Performance | Response time, throughput |

| Errors | Error rate, types |

| Resources | CPU, memory, disk |

Alert Severity Strategy

| Level | Response |

|-------|----------|

| Critical | Immediate action |

| Warning | Investigate soon |

| Info | Review daily |

Monitoring Tool Selection

| Need | Options |

|------|---------|

| Simple/Free | PM2 metrics, htop |

| Full observability | Grafana, Datadog |

| Error tracking | Sentry |

| Uptime | UptimeRobot, Pingdom |

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3. Log Management Principles

Log Strategy

| Log Type | Purpose |

|----------|---------|

| Application logs | Debug, audit |

| Access logs | Traffic analysis |

| Error logs | Issue detection |

Log Principles

1.Rotate logs to prevent disk fill

2.Structured logging (JSON) for parsing

3.Appropriate levels (error/warn/info/debug)

4.No sensitive data in logs

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4. Scaling Decisions

When to Scale

| Symptom | Solution |

|---------|----------|

| High CPU | Add instances (horizontal) |

| High memory | Increase RAM or fix leak |

| Slow response | Profile first, then scale |

| Traffic spikes | Auto-scaling |

Scaling Strategy

| Type | When to Use |

|------|-------------|

| Vertical | Quick fix, single instance |

| Horizontal | Sustainable, distributed |

| Auto | Variable traffic |

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5. Health Check Principles

What Constitutes Healthy

| Check | Meaning |

|-------|---------|

| HTTP 200 | Service responding |

| Database connected | Data accessible |

| Dependencies OK | External services reachable |

| Resources OK | CPU/memory not exhausted |

Health Check Implementation

●Simple: Just return 200

●Deep: Check all dependencies

●Choose based on load balancer needs

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6. Security Principles

| Area | Principle |

|------|-----------|

| Access | SSH keys only, no passwords |

| Firewall | Only needed ports open |

| Updates | Regular security patches |

| Secrets | Environment vars, not files |

| Audit | Log access and changes |

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7. Troubleshooting Priority

When something's wrong:

1.Check if running (process status)

2.Check logs (error messages)

3.Check resources (disk, memory, CPU)

4.Check network (ports, DNS)

5.Check dependencies (database, APIs)

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8. Anti-Patterns

| ❌ Don't | ✅ Do |

|----------|-------|

| Run as root | Use non-root user |

| Ignore logs | Set up log rotation |

| Skip monitoring | Monitor from day one |

| Manual restarts | Auto-restart config |

| No backups | Regular backup schedule |

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> Remember: A well-managed server is boring. That's the goal.

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