AWS RDS Database Overview
Amazon RDS simplifies relational database deployment and operations. Support multiple database engines with automated backups, replication, encryption, and high availability through Multi-AZ deployments.
When to Use PostgreSQL and MySQL applications Transactional databases and OLTP Oracle and Microsoft SQL Server workloads Read-heavy applications with replicas Development and staging environments Data requiring ACID compliance Applications needing automatic backups Disaster recovery scenarios Implementation Examples 1. RDS Instance Creation with AWS CLI
Create DB subnet group
aws rds create-db-subnet-group \ --db-subnet-group-name app-db-subnet \ --db-subnet-group-description "App database subnet" \ --subnet-ids subnet-12345 subnet-67890
Create security group for RDS
aws ec2 create-security-group \ --group-name rds-sg \ --description "RDS security group" \ --vpc-id vpc-12345
Allow inbound PostgreSQL
aws ec2 authorize-security-group-ingress \ --group-id sg-rds123 \ --protocol tcp \ --port 5432 \ --source-security-group-id sg-app123
Create RDS instance
aws rds create-db-instance \ --db-instance-identifier myapp-db \ --db-instance-class db.t3.micro \ --engine postgres \ --engine-version 15.2 \ --master-username admin \ --master-user-password MySecurePassword123! \ --allocated-storage 100 \ --storage-type gp3 \ --db-subnet-group-name app-db-subnet \ --vpc-security-group-ids sg-rds123 \ --multi-az \ --storage-encrypted \ --kms-key-id arn:aws:kms:region:account:key/id \ --backup-retention-period 30 \ --preferred-backup-window "03:00-04:00" \ --preferred-maintenance-window "mon:04:00-mon:05:00" \ --enable-clouwatch-logs-exports postgresql \ --enable-iam-database-authentication
Create read replica
aws rds create-db-instance-read-replica \ --db-instance-identifier myapp-db-read \ --source-db-instance-identifier myapp-db
Take manual snapshot
aws rds create-db-snapshot \ --db-snapshot-identifier myapp-db-backup-2024 \ --db-instance-identifier myapp-db
Describe RDS instance
aws rds describe-db-instances \ --db-instance-identifier myapp-db \ --query 'DBInstances[0].[DBInstanceIdentifier,DBInstanceStatus,Endpoint.Address]'
- Terraform RDS Configuration
rds.tf
terraform { required_providers { aws = { source = "hashicorp/aws" version = "~> 5.0" } } }
provider "aws" { region = "us-east-1" }
DB subnet group
resource "aws_db_subnet_group" "app" { name = "app-db-subnet" subnet_ids = [aws_subnet.private1.id, aws_subnet.private2.id]
tags = { Name = "app-db-subnet" } }
Security group
resource "aws_security_group" "rds" { name_prefix = "rds-" vpc_id = aws_vpc.main.id
ingress { from_port = 5432 to_port = 5432 protocol = "tcp" security_groups = [aws_security_group.app.id] }
egress { from_port = 0 to_port = 0 protocol = "-1" cidr_blocks = ["0.0.0.0/0"] } }
KMS key for encryption
resource "aws_kms_key" "rds" { description = "RDS encryption key" deletion_window_in_days = 10 enable_key_rotation = true }
resource "aws_kms_alias" "rds" { name = "alias/rds-key" target_key_id = aws_kms_key.rds.key_id }
RDS instance
resource "aws_db_instance" "app" { identifier = "myapp-db" engine = "postgres" engine_version = "15.2" instance_class = "db.t3.micro" allocated_storage = 100 storage_type = "gp3" storage_encrypted = true kms_key_id = aws_kms_key.rds.arn
db_name = "appdb" username = "admin" password = random_password.db_password.result
db_subnet_group_name = aws_db_subnet_group.app.name vpc_security_group_ids = [aws_security_group.rds.id]
multi_az = true publicly_accessible = false
backup_retention_period = 30 backup_window = "03:00-04:00" maintenance_window = "mon:04:00-mon:05:00" copy_tags_to_snapshot = true
enabled_cloudwatch_logs_exports = ["postgresql"]
enable_iam_database_authentication = true
deletion_protection = true
skip_final_snapshot = false final_snapshot_identifier = "myapp-db-final-snapshot-${formatdate("YYYY-MM-DD-hhmm", timestamp())}"
tags = { Name = "myapp-db" } }
Generate random password
resource "random_password" "db_password" { length = 16 special = true }
Store password in Secrets Manager
resource "aws_secretsmanager_secret" "db_password" { name_prefix = "rds/myapp/" recovery_window_in_days = 7 }
resource "aws_secretsmanager_secret_version" "db_password" { secret_id = aws_secretsmanager_secret.db_password.id secret_string = jsonencode({ username = aws_db_instance.app.username password = random_password.db_password.result engine = "postgres" host = aws_db_instance.app.address port = aws_db_instance.app.port dbname = aws_db_instance.app.db_name }) }
Read replica
resource "aws_db_instance" "read_replica" { identifier = "myapp-db-read" replicate_source_db = aws_db_instance.app.identifier instance_class = "db.t3.micro" publicly_accessible = false
tags = { Name = "myapp-db-read" } }
Enhanced monitoring role
resource "aws_iam_role" "rds_monitoring" { assume_role_policy = jsonencode({ Version = "2012-10-17" Statement = [{ Action = "sts:AssumeRole" Effect = "Allow" Principal = { Service = "monitoring.rds.amazonaws.com" } }] }) }
resource "aws_iam_role_policy_attachment" "rds_monitoring" { role = aws_iam_role.rds_monitoring.name policy_arn = "arn:aws:iam::aws:policy/service-role/AmazonRDSEnhancedMonitoringRole" }
CloudWatch alarms
resource "aws_cloudwatch_metric_alarm" "db_cpu" { alarm_name = "rds-high-cpu" comparison_operator = "GreaterThanThreshold" evaluation_periods = 2 metric_name = "CPUUtilization" namespace = "AWS/RDS" period = 300 statistic = "Average" threshold = 80 alarm_description = "Alert when RDS CPU exceeds 80%"
dimensions = { DBInstanceIdentifier = aws_db_instance.app.id } }
resource "aws_cloudwatch_metric_alarm" "db_connections" { alarm_name = "rds-high-connections" comparison_operator = "GreaterThanThreshold" evaluation_periods = 1 metric_name = "DatabaseConnections" namespace = "AWS/RDS" period = 300 statistic = "Average" threshold = 80 alarm_description = "Alert when database connections exceed 80"
dimensions = { DBInstanceIdentifier = aws_db_instance.app.id } }
Outputs
output "db_endpoint" { value = aws_db_instance.app.endpoint description = "RDS endpoint address" }
output "db_password_secret" { value = aws_secretsmanager_secret.db_password.arn description = "Secret Manager ARN for database credentials" }
- Database Connection and Configuration
Connect to RDS instance
psql -h myapp-db.xxxx.us-east-1.rds.amazonaws.com \ -U admin \ -d appdb \ -p 5432
Create database user with IAM authentication
psql -h myapp-db.xxxx.us-east-1.rds.amazonaws.com \ -U admin \ -d appdb << EOF CREATE USER app_user; GRANT CONNECT ON DATABASE appdb TO app_user; GRANT USAGE ON SCHEMA public TO app_user; GRANT SELECT, INSERT, UPDATE, DELETE ON ALL TABLES IN SCHEMA public TO app_user; ALTER ROLE app_user WITH PASSWORD 'MySecurePassword123!'; EOF
Export database
pg_dump -h myapp-db.xxxx.us-east-1.rds.amazonaws.com \ -U admin \ appdb > backup.sql
Import database
psql -h myapp-db.xxxx.us-east-1.rds.amazonaws.com \ -U admin \ appdb < backup.sql
Best Practices ✅ DO Use Multi-AZ for production Enable automated backups Use encryption at rest and in transit Implement IAM database authentication Create read replicas for scaling Monitor performance metrics Set up CloudWatch alarms Store credentials in Secrets Manager Use parameter groups for configuration ❌ DON'T Store passwords in code Disable encryption Use public accessibility in production Ignore backup retention Skip automated backups Create databases without Multi-AZ Monitoring CloudWatch metrics (CPU, connections, storage) Enhanced Monitoring with OS metrics RDS Performance Insights AWS CloudTrail for API logging Custom CloudWatch Logs from applications Resources AWS RDS Documentation RDS Best Practices PostgreSQL on RDS