aa2bcfce46
aula-07: Criação de imagem Talos customizada na Hetzner Cloud - Usa Talos Factory para gerar imagem ARM64/AMD64 - Inclui extensões: qemu-guest-agent, hcloud aula-08: Provisionamento de cluster Kubernetes Talos via OpenTofu - 3 Control Planes em HA (CAX11 ARM64) - 1 Worker Node (CAX11 ARM64) - Rede privada, Floating IP, Firewall - Cluster Autoscaler para Hetzner (0-5 workers extras) - Setup interativo com validação de pré-requisitos - Custo estimado: ~€18/mês (base) Também inclui: - .gitignore para ignorar arquivos sensíveis - CLAUDE.md com instruções do projeto
115 lines
4.7 KiB
Markdown
115 lines
4.7 KiB
Markdown
# CLAUDE.md
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This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
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## Project Overview
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This is a workshop repository for teaching Docker and Kubernetes concepts, specifically focusing on container health checks and liveness probes. It contains a deliberately "buggy" Node.js app that hangs after a configurable number of requests to demonstrate how container orchestration handles unhealthy containers.
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## Repository Structure
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- **aula-01/**: Docker Compose lesson - basic container deployment with restart policies
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- **aula-02/**: Kubernetes lesson - deployment with liveness probes and ConfigMaps
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- **aula-03/**: Kubernetes lesson - high availability with replicas and readiness probes
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- **aula-04/**: Kubernetes lesson - NGINX Ingress with Keep Request (Lua) for zero-downtime
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- **aula-05/**: Kubernetes lesson - KEDA + Victoria Metrics for metrics-based auto-scaling
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- **aula-06/**: Kubernetes lesson - n8n deployment via Helm with Queue Mode (workers, webhooks, PostgreSQL, Redis)
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- **aula-07/**: Talos Linux - creating custom Talos image for Hetzner Cloud
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- **aula-08/**: OpenTofu - provisioning HA Talos Kubernetes cluster on Hetzner Cloud
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## Running the Examples
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### Aula 01 (Docker Compose)
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```bash
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cd aula-01
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docker-compose up
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```
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The app runs on port 3000. After MAX_REQUESTS (default 3), the app stops responding.
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### Aula 02 (Kubernetes)
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```bash
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cd aula-02
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kubectl apply -f configmap.yaml
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kubectl apply -f deployment.yaml
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kubectl apply -f service.yaml
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```
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Access via NodePort 30080. The liveness probe at `/health` will detect when the app hangs and restart the container.
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### Aula 03 (Kubernetes - High Availability)
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```bash
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cd aula-03
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kubectl apply -f configmap.yaml
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kubectl apply -f deployment.yaml
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kubectl apply -f service.yaml
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```
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Builds on Aula 02 with multiple replicas and a readiness probe. When one pod hangs, the others continue serving requests. The readiness probe removes unhealthy pods from the Service immediately, while the liveness probe restarts them.
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### Aula 04 (Kubernetes - NGINX Ingress with Keep Request)
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Requires NGINX Ingress Controller with Lua support.
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```bash
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cd aula-04
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kubectl apply -f configmap.yaml
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kubectl apply -f deployment.yaml
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kubectl apply -f service.yaml
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kubectl apply -f ingress-nginx.yaml
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```
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Access via NGINX Ingress. The Keep Request pattern uses Lua to hold requests when backends are unavailable, waiting up to 99s for a pod to become ready instead of returning 503 immediately. This eliminates user-visible failures during pod restarts.
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### Aula 05 (Kubernetes - KEDA Auto-scaling)
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```bash
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cd aula-05
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./setup.sh
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```
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Installs Victoria Metrics (metrics collection), KEDA (event-driven autoscaling), and NGINX Ingress. The ScaledObject monitors metrics like unavailable pods and restart counts, automatically scaling the deployment from 5 to 30 replicas based on demand.
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### Aula 06 (Kubernetes - n8n via Helm)
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```bash
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cd aula-06
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./setup.sh
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```
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Deploys n8n workflow automation platform via Helm chart with Queue Mode architecture: main node, workers (2-5 replicas with HPA), webhooks (1-3 replicas with HPA), PostgreSQL, and Redis. Access via http://n8n.localhost (requires NGINX Ingress).
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### Aula 07 (Talos Linux - Custom Image)
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Follow the instructions in `aula-07/README.md` to create a custom Talos Linux image on Hetzner Cloud using Talos Factory. This is a prerequisite for Aula 08.
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### Aula 08 (OpenTofu - Talos Cluster on Hetzner Cloud)
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```bash
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cd aula-08
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./setup.sh
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```
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Provisions a full HA Kubernetes cluster on Hetzner Cloud using OpenTofu:
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- 3x Control Plane nodes (CAX11 ARM64)
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- 1x Worker node (CAX11 ARM64)
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- Private network, Floating IP, Firewall
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- Cluster Autoscaler support (1-5 workers)
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- Estimated cost: ~€18/month (base), up to ~€33/month with max autoscaling
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Prerequisites:
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- OpenTofu (`brew install opentofu`)
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- talosctl (`brew install siderolabs/tap/talosctl`)
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- kubectl
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- Hetzner Cloud API token
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- Talos image ID from Aula 07
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Optional - Enable cluster autoscaling:
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```bash
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./install-autoscaler.sh
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```
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This installs the Kubernetes Cluster Autoscaler configured for Hetzner Cloud, automatically scaling workers from 1 to 5 based on pending pods.
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To destroy the infrastructure: `./cleanup.sh`
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## App Behavior
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The Node.js app (`app.js`) is intentionally designed to:
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1. Accept requests normally until `MAX_REQUESTS` is reached
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2. Stop responding (hang) after the limit, simulating a crashed but running process
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3. The `/health` endpoint also stops responding when the app is "stuck"
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This behavior demonstrates why process-level monitoring (restart: always) is insufficient and why application-level health checks (liveness probes) are necessary.
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## Environment Variables
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- `MAX_REQUESTS`: Number of requests before the app hangs (default: 3)
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