fix(aula-08): prevenir volume stalling com CSI tolerations e PDB

- Adicionar hcloud-csi-values.yaml com tolerations para node failures
- Configurar 2 replicas do CSI controller para HA
- Criar statefulset-pdb.yaml para proteger StatefulSets durante drain
- Documentar troubleshooting de volumes stuck no README

aula-08/README.md

@@ -202,7 +202,47 @@ aula-08/
 ├── install-nginx-ingress.sh   # Instala NGINX Ingress com LB
 ├── install-metrics-server.sh  # Instala Metrics Server (kubectl top, HPA)
 ├── nginx-ingress-values.yaml  # Configuracao do NGINX Ingress
-└── talos-patches/             # Patches de configuracao Talos
-    ├── control-plane.yaml
-    └── worker.yaml
+├── talos-patches/             # Patches de configuracao Talos
+│   ├── control-plane.yaml
+│   └── worker.yaml
+├── hcloud-csi-values.yaml     # Configuracao do CSI Driver
+└── statefulset-pdb.yaml       # PDB para proteger StatefulSets
 ```
+
+## Troubleshooting: Volume Stuck
+
+Se um pod ficar `Pending` aguardando volume:
+
+### 1. Verificar VolumeAttachment
+
+```bash
+kubectl get volumeattachments
+kubectl describe volumeattachment <name>
+```
+
+### 2. Se o node de origem nao existe mais
+
+```bash
+# Deletar o VolumeAttachment orfao (seguro pois node nao existe)
+kubectl delete volumeattachment <name>
+```
+
+### 3. Se o node existe mas pod morreu
+
+```bash
+# Aguardar - Kubernetes vai liberar automaticamente
+# Timeout padrao: 6 minutos
+```
+
+### 4. Verificar no Hetzner
+
+```bash
+hcloud volume list
+# Se volume mostra attached a server que nao existe, abrir ticket
+```
+
+### Limitacoes do Block Storage
+
+- Volumes Hetzner sao **RWO** (ReadWriteOnce) - single-attach por design
+- Podem ficar stuck por ate 6 min (timeout do Kubernetes)
+- Se node morrer abruptamente, recuperacao pode ser manual (deletar VolumeAttachment)

aula-08/hcloud-csi-values.yaml

@@ -0,0 +1,13 @@
+# Configuracoes para graceful handling de node failures
+controller:
+  tolerations:
+    - key: "node.kubernetes.io/unreachable"
+      operator: "Exists"
+      effect: "NoExecute"
+      tolerationSeconds: 60
+    - key: "node.kubernetes.io/not-ready"
+      operator: "Exists"
+      effect: "NoExecute"
+      tolerationSeconds: 60
+  # Mais replicas para HA do controller
+  replicaCount: 2

aula-08/setup.sh

@@ -534,6 +534,7 @@ log_info "Instalando CSI Driver via Helm..."
 
 helm upgrade --install hcloud-csi hcloud/hcloud-csi \
     -n kube-system \
+    -f "$SCRIPT_DIR/hcloud-csi-values.yaml" \
     --wait \
     --timeout 5m
 
@@ -543,6 +544,11 @@ log_success "Hetzner CSI Driver instalado!"
 log_info "Verificando StorageClass..."
 kubectl get storageclass hcloud-volumes
 
+# Configurar PDB para StatefulSets (protecao durante drain)
+log_info "Criando PodDisruptionBudget para StatefulSets..."
+kubectl apply -f "$SCRIPT_DIR/statefulset-pdb.yaml"
+log_success "PDB criado"
+
 echo ""
 
 ############################################################

aula-08/statefulset-pdb.yaml

@@ -0,0 +1,12 @@
+# PodDisruptionBudget para proteger StatefulSets durante node drain
+# Evita que volumes fiquem stuck durante operacoes de manutencao
+apiVersion: policy/v1
+kind: PodDisruptionBudget
+metadata:
+  name: statefulset-pdb
+  namespace: default
+spec:
+  minAvailable: 0
+  selector:
+    matchLabels:
+      app.kubernetes.io/component: primary