Terraformにて、AuroraやElastiCacheのスペック変更はデフォルトでメンテナンスウィンドウでの変更になる

## Auroraクラスター
resource "aws_rds_cluster" "aurora_cluster" {
  cluster_identifier     = "aurora-immediately-cluster"
  engine                 = "aurora-mysql"
  engine_version         = "8.0.mysql_aurora.3.08.2"
  master_username        = "admin"
  manage_master_user_password = true
  backup_retention_period = 7
  preferred_backup_window      = "18:30-19:30"
  preferred_maintenance_window = "tue:17:00-tue:18:00"
  deletion_protection    = false
  skip_final_snapshot    = false
  storage_encrypted      = true
  port                   = 3306
  vpc_security_group_ids = [aws_security_group.aurora_sg.id]
  db_subnet_group_name        = aws_db_subnet_group.aurora_subnet_group.name
  db_cluster_parameter_group_name = aws_rds_cluster_parameter_group.aurora_cluster_pg.name
  enabled_cloudwatch_logs_exports = ["error", "slowquery"]
  copy_tags_to_snapshot = true
  tags = {
    Name = "aurora-immediately-test-cluster"
  }
}

## Auroraインスタンス（ライターインスタンス）
resource "aws_rds_cluster_instance" "aurora_primary" {
  cluster_identifier = aws_rds_cluster.aurora_cluster.id
  identifier         = "aurora-immediately-cluster-0"
  engine             = aws_rds_cluster.aurora_cluster.engine
  engine_version     = aws_rds_cluster.aurora_cluster.engine_version
  # インスタンスクラス
  instance_class     = "db.t4g.medium"
  db_parameter_group_name = aws_db_parameter_group.aurora_instance_pg.name
  performance_insights_enabled = false
  auto_minor_version_upgrade = true
  # 変更の即座適用
  # apply_immediately = true
  tags = {
    Name = "aurora-immediately-test-cluster-0"
  }
}