RDS — Bancos Relacionais Gerenciados

Aula 6 de 8

Amazon RDS

RDS gerencia bancos relacionais: MySQL, PostgreSQL, MariaDB, SQL Server, Oracle e Aurora.

Por que RDS em vez de instalar na EC2?

Recurso	RDS	EC2 + DB
Backup automático	Nativo	Configurar manualmente
Multi-AZ failover	Nativo	Configurar manualmente
Read replicas	Gerenciado	Configurar manualmente
Patching	Automático	Manual
Storage auto-scaling	Sim	Não

Lab: Criar RDS PostgreSQL

# 1. Criar subnet group (subnets privadas)
aws rds create-db-subnet-group \
  --db-subnet-group-name meu-db-group \
  --subnet-ids subnet-priv-a subnet-priv-b \
  --db-subnet-group-description "Subnets privadas RDS"

# 2. Criar security group RDS
RDS_SG=$(aws ec2 create-security-group \
  --group-name rds-sg \
  --description "Acesso ao RDS" \
  --vpc-id $VPC_ID --query 'GroupId' --output text)

aws ec2 authorize-security-group-ingress \
  --group-id $RDS_SG \
  --protocol tcp --port 5432 \
  --source-group sg-app  # só app pode conectar

# 3. Criar instância RDS
aws rds create-db-instance \
  --db-instance-identifier meu-postgres \
  --db-instance-class db.t3.medium \
  --engine postgres \
  --engine-version 16 \
  --master-username admin \
  --master-user-password SenhaSegura123! \
  --allocated-storage 100 \
  --storage-type gp3 \
  --db-subnet-group-name meu-db-group \
  --vpc-security-group-ids $RDS_SG \
  --backup-retention-period 7 \
  --preferred-backup-window "03:00-04:00" \
  --multi-az \
  --storage-encrypted \
  --deletion-protection

Multi-AZ e Read Replicas

# Multi-AZ (failover automático entre AZs)
aws rds modify-db-instance \
  --db-instance-identifier meu-postgres \
  --multi-az \
  --apply-immediately

# Read Replica (escala leitura)
aws rds create-db-instance-read-replica \
  --db-instance-identifier meu-postgres-replica \
  --source-db-instance-identifier meu-postgres \
  --db-instance-class db.t3.large \
  --region us-west-2  # cross-region replica

Aurora — AWS-native DB

# Aurora é mais rápido e escalável que RDS padrão
aws rds create-db-cluster \
  --db-cluster-identifier meu-aurora \
  --engine aurora-postgresql \
  --engine-version 16 \
  --master-username admin \
  --master-user-password SenhaSegura123!

Backup e Restore

# Snapshot manual
aws rds create-db-snapshot \
  --db-instance-identifier meu-postgres \
  --db-snapshot-identifier meu-postgres-bkp-2024

# Restaurar snapshot para nova instância
aws rds restore-db-instance-from-db-snapshot \
  --db-instance-identifier meu-postgres-restaurado \
  --db-snapshot-identifier meu-postgres-bkp-2024

# Point-in-Time Recovery (PITR)
aws rds restore-db-instance-to-point-in-time \
  --source-db-instance-identifier meu-postgres \
  --target-db-instance-identifier meu-postgres-pitr \
  --restore-time "2024-06-01T02:00:00Z"

Performance Insights

# Habilitar Performance Insights
aws rds modify-db-instance \
  --db-instance-identifier meu-postgres \
  --enable-performance-insights \
  --performance-insights-retention-period 7

# CloudWatch Metrics
aws cloudwatch get-metric-statistics \
  --namespace AWS/RDS \
  --metric-name DatabaseConnections \
  --dimensions Name=DBInstanceIdentifier,Value=meu-postgres \
  --start-time 2024-06-01T00:00:00Z \
  --end-time 2024-06-02T00:00:00Z \
  --period 300 --statistics Average

Connection Pooling (RDS Proxy)

# RDS Proxy — gerencia pool de conexões (serverless)
aws rds create-db-proxy \
  --db-proxy-name meu-proxy \
  --engine-family POSTGRESQL \
  --auth '[{ "AuthScheme": "SECRETS", "SecretArn": "arn:aws:secretsmanager:xxx:secret:xxx" }]' \
  --role-arn arn:aws:iam::xxx:role/rds-proxy-role \
  --vpc-subnet-ids subnet-priv-a subnet-priv-b

RDS Proxy é essencial para Lambda + RDS (evita esgotamento de conexões). Multi-AZ é obrigatório em produção. Sempre use Deletion Protection.