# Demo Nginx Documentation

Документация для demo-nginx deployment с автоматическим и ручным rollback.

---

## 📚 Available Documentation

### [ROLLBACK_MANUAL.md](./ROLLBACK_MANUAL.md)
**Comprehensive Manual Rollback Guide**

Полная документация по функции ручного rollback:
- 3 способа rollback (IMAGE_TAG, REVISION, GIT_COMMIT)
- Setup guide
- Troubleshooting со всеми fixes
- Best practices
- Examples
- FAQ

**When to use:** Нужна детальная информация или troubleshooting

---

### [ROLLBACK_QUICK_REF.md](./ROLLBACK_QUICK_REF.md)
**Quick Reference Card**

Краткая справка для быстрого использования:
- Quick start (2 минуты)
- 3 способа rollback
- Emergency procedure
- Verification commands
- Checklist

**When to use:** Быстрый rollback в production

---

## 🎯 Quick Links

### Rollback Feature
- **Full Guide:** [ROLLBACK_MANUAL.md](./ROLLBACK_MANUAL.md)
- **Quick Ref:** [ROLLBACK_QUICK_REF.md](./ROLLBACK_QUICK_REF.md)
- **Jenkinsfile:** [Jenkinsfile.rollback](../Jenkinsfile.rollback)
- **CI/CD Guide:** [../../../CICD_GUIDE.md](../../../CICD_GUIDE.md)

### Related Resources
- **Jenkins RBAC:** [apps/jenkins/rbac.yaml](../../jenkins/rbac.yaml)
- **Deployment:** [deployment.yaml](../deployment.yaml)
- **Main CI/CD:** [Jenkinsfile](../Jenkinsfile)

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## 🚀 Quick Start

### Manual Rollback (2 minutes)

```
1. Jenkins → demo-nginx-rollback
2. IMAGE_TAG + main-21
3. SKIP_HEALTH_CHECK: true
4. Build
```

See [ROLLBACK_QUICK_REF.md](./ROLLBACK_QUICK_REF.md) for details.

---

### Emergency Rollback (30 seconds)

```bash
kubectl rollout undo deployment/demo-nginx -n demo-app
```

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## 📊 Features Summary

### Manual Rollback
✅ 3 rollback methods (IMAGE_TAG, REVISION, GIT_COMMIT)  
✅ GitOps sync (auto-commit to Git)  
✅ Zero downtime (rolling updates)  
✅ DRY_RUN mode (safe testing)  
✅ Full RBAC permissions  
✅ Input validation (auto-trim)  
✅ Retry logic (5 attempts)  
⚠️ Health check optional (use SKIP_HEALTH_CHECK=true)  

### Automatic Rollback
✅ Triggered on deployment failure  
✅ Saves previous state  
✅ Kubernetes rollback  
✅ Git revert  
✅ Health checks  
✅ Timeout protection  

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## 🐛 All Fixes Applied

| # | Issue | Fix | Status | Doc |
|---|-------|-----|--------|-----|
| 1 | Container name | Use `nginx` | ✅ | [Link](./ROLLBACK_MANUAL.md#issue-1-container-name-error--fixed) |
| 2 | Whitespace | Auto-trim | ✅ | [Link](./ROLLBACK_MANUAL.md#issue-2-whitespace-in-input--fixed) |
| 3 | RBAC | pods/exec perm | ✅ | [Link](./ROLLBACK_MANUAL.md#issue-3-rbac-permissions--fixed) |
| 4 | Health timing | SKIP option | ⚠️ | [Link](./ROLLBACK_MANUAL.md#issue-4-health-check-timing--workaround) |
| 5 | Bash loop | Explicit list | ✅ | [Link](./ROLLBACK_MANUAL.md#issue-5-bash-loop-syntax--fixed) |

---

## 💡 Recommended Reading Order

### For New Users:
1. Start → [ROLLBACK_QUICK_REF.md](./ROLLBACK_QUICK_REF.md)
2. Practice → Follow quick start
3. Deep Dive → [ROLLBACK_MANUAL.md](./ROLLBACK_MANUAL.md)

### For Troubleshooting:
1. Check → [ROLLBACK_MANUAL.md - Troubleshooting](./ROLLBACK_MANUAL.md#troubleshooting--fixes)
2. Verify → [ROLLBACK_QUICK_REF.md - Verification](./ROLLBACK_QUICK_REF.md#-verify-rollback)
3. Support → [ROLLBACK_MANUAL.md - Support](./ROLLBACK_MANUAL.md#support)

### For Emergency:
1. Fast → [ROLLBACK_QUICK_REF.md - Emergency](./ROLLBACK_QUICK_REF.md#-emergency-rollback-30-seconds)
2. Alternative → [ROLLBACK_MANUAL.md - Emergency](./ROLLBACK_MANUAL.md#emergency-rollback-procedure)

---

## 🎓 Key Concepts

### Rollback Methods Comparison

| Method | Speed | Precision | Use Case |
|--------|-------|-----------|----------|
| IMAGE_TAG | ⚡⚡⚡ | 🎯 High | Known build number |
| REVISION | ⚡⚡ | 🎯 Medium | Recent rollback |
| GIT_COMMIT | ⚡ | 🎯🎯 High | Exact code state |

### When to Use What

**Use IMAGE_TAG when:**
- You know the build number (main-21)
- Quick rollback needed
- Most common scenario

**Use REVISION_NUMBER when:**
- Need to go back N versions
- Don't remember exact tag
- Working with kubectl history

**Use GIT_COMMIT when:**
- Need exact code state
- Multiple changes in one build
- Precise rollback required

---

## 📈 Monitoring

### Check Rollback Status

```bash
# Deployment status
kubectl get deployment demo-nginx -n demo-app

# Pod status
kubectl get pods -n demo-app -l app=demo-nginx

# Rollout history
kubectl rollout history deployment/demo-nginx -n demo-app

# ArgoCD status
kubectl get application demo-nginx -n argocd
```

### Grafana Queries

```promql
# Rollback count
sum(increase(deployment_rollback_total[1h])) by (deployment)

# Rollback rate
rate(deployment_rollback_total[5m])
```

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## ❓ FAQ

### Q: Какой метод rollback использовать?
**A:** Для большинства случаев используй IMAGE_TAG - самый быстрый и простой.

### Q: Health check всегда падает, это баг?
**A:** Нет, это timing issue во время rolling update. Используй `SKIP_HEALTH_CHECK: true` и проверь вручную через минуту.

### Q: Как быстро откатиться в emergency?
**A:** Используй `kubectl rollout undo` (30 секунд) или Jenkins с SKIP_HEALTH_CHECK (2 минуты).

### Q: Где полная документация?
**A:** [ROLLBACK_MANUAL.md](./ROLLBACK_MANUAL.md) - comprehensive guide со всеми details.

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## 🆘 Support

**Need Help?**

1. Check [ROLLBACK_MANUAL.md - Troubleshooting](./ROLLBACK_MANUAL.md#troubleshooting--fixes)
2. Review [ROLLBACK_MANUAL.md - FAQ](./ROLLBACK_MANUAL.md#faq)
3. Check Jenkins console output
4. Verify RBAC permissions
5. Review pod status and logs

**Still stuck?**
- Jenkins logs: Jenkins → Build → Console Output
- K8s events: `kubectl get events -n demo-app`
- Pod logs: `kubectl logs -n demo-app -l app=demo-nginx`

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## 📝 Documentation Updates

**Last Updated:** 2026-01-06  
**Version:** 1.0  
**Status:** Production Ready ✅

**Recent Changes:**
- ✅ Added comprehensive manual rollback guide
- ✅ Added quick reference card
- ✅ Documented all 5 fixes
- ✅ Added examples and best practices
- ✅ Production-ready feature

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**Ready to rollback? Start with [Quick Reference](./ROLLBACK_QUICK_REF.md)! 🚀**