server-management

# Server Management > Server management principles for production operations. > **Learn to THINK, not memorize commands.** --- ## 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 | --- ## 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 | --- ## 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 --- ## 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 | --- ## 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 --- ## 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 | --- ## 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) --- ## 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 | --- > **Remember:** A well-managed server is boring. That's the goal.