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giuseppe-trisciuoglio/developer-kit

Comprehensive developer toolkit providing reusable skills for Java/Spring Boot, TypeScript/NestJS/React/Next.js, Python, PHP, AWS CloudFormation, AI/RAG, DevOps, and more.

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troubleshooting.mdplugins/developer-kit-java/skills/aws-rds-spring-boot-integration/references/

AWS RDS Aurora Troubleshooting Guide

Common Issues and Solutions

Connection Timeout to Aurora Cluster

Error: Communications link failure or Connection timed out

Solutions:

  • Verify security group inbound rules allow traffic on port 3306 (MySQL) or 5432 (PostgreSQL)
  • Check Aurora cluster endpoint is correct (cluster vs instance endpoint)
  • Ensure your IP/CIDR is whitelisted in security group
  • Verify VPC and subnet configuration
  • Check if Aurora cluster is in the same VPC or VPC peering is configured
# Test connection from EC2/local machine
telnet myapp-aurora-cluster.cluster-abc123xyz.us-east-1.rds.amazonaws.com 3306

Access Denied for User

Error: Access denied for user 'admin'@'...'

Solutions:

  • Verify master username and password are correct
  • Check if IAM authentication is required but not configured
  • Reset master password in Aurora console if needed
  • Verify user permissions in database
-- Check user permissions
SHOW GRANTS FOR 'admin'@'%';

Database Not Found

Error: Unknown database 'devops'

Solutions:

  • Verify initial database name was created with cluster
  • Create database manually using MySQL/PostgreSQL client
  • Check database name in JDBC URL matches existing database
-- Connect to Aurora and create database
CREATE DATABASE devops CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;

SSL Connection Issues

Error: SSL connection error or Certificate validation failed

Solutions:

# Option 1: Disable SSL verification (NOT recommended for production)
spring.datasource.url=jdbc:mysql://...?useSSL=false

# Option 2: Properly configure SSL with RDS certificate
spring.datasource.url=jdbc:mysql://...?useSSL=true&requireSSL=true&verifyServerCertificate=true&trustCertificateKeyStoreUrl=file:///path/to/global-bundle.pem

# Option 3: Trust all certificates (NOT recommended for production)
spring.datasource.url=jdbc:mysql://...?useSSL=true&requireSSL=true&verifyServerCertificate=false

Too Many Connections

Error: Too many connections or Connection pool exhausted

Solutions:

  • Review Aurora instance max_connections parameter
  • Optimize HikariCP pool size
  • Check for connection leaks in application code
# Reduce pool size
spring.datasource.hikari.maximum-pool-size=15
spring.datasource.hikari.minimum-idle=5

# Enable leak detection
spring.datasource.hikari.leak-detection-threshold=60000

Check Aurora max_connections:

SHOW VARIABLES LIKE 'max_connections';
-- Default for Aurora: depends on instance class
-- db.r6g.large: ~1000 connections

Slow Query Performance

Error: Queries taking longer than expected

Solutions:

  • Enable slow query log in Aurora parameter group
  • Review connection pool settings
  • Check Aurora instance metrics in CloudWatch
  • Optimize queries and add indexes
# Enable query logging (development only)
logging.level.org.hibernate.SQL=DEBUG
logging.level.org.hibernate.type.descriptor.sql.BasicBinder=TRACE

Failover Delays

Error: Application freezes during Aurora failover

Solutions:

  • Configure connection timeout appropriately
  • Use cluster endpoint (not instance endpoint)
  • Implement connection retry logic
spring.datasource.hikari.connection-timeout=20000
spring.datasource.hikari.validation-timeout=5000
spring.datasource.url=jdbc:mysql://...?failOverReadOnly=false&maxReconnects=3

Testing Aurora Connection

Connection Test with Spring Boot Application

Create a Simple Test Endpoint:

@RestController
@RequestMapping("/api/health")
public class DatabaseHealthController {

    @Autowired
    private DataSource dataSource;

    @GetMapping("/db-connection")
    public ResponseEntity<Map<String, Object>> testDatabaseConnection() {
        Map<String, Object> response = new HashMap<>();

        try (Connection connection = dataSource.getConnection()) {
            response.put("status", "success");
            response.put("database", connection.getCatalog());
            response.put("url", connection.getMetaData().getURL());
            response.put("connected", true);
            return ResponseEntity.ok(response);
        } catch (Exception e) {
            response.put("status", "failed");
            response.put("error", e.getMessage());
            response.put("connected", false);
            return ResponseEntity.status(HttpStatus.SERVICE_UNAVAILABLE).body(response);
        }
    }
}

Test with cURL:

curl http://localhost:8080/api/health/db-connection

Verify Aurora Connection with MySQL/PostgreSQL Client

MySQL Client Connection:

# Connect to Aurora MySQL cluster
mysql -h myapp-aurora-cluster.cluster-abc123xyz.us-east-1.rds.amazonaws.com \
      -P 3306 \
      -u admin \
      -p devops

# Verify connection
SHOW DATABASES;
SELECT @@version;
SHOW VARIABLES LIKE 'aurora_version';

PostgreSQL Client Connection:

# Connect to Aurora PostgreSQL
psql -h myapp-aurora-pg-cluster.cluster-abc123xyz.us-east-1.rds.amazonaws.com \
     -p 5432 \
     -U admin \
     -d devops

# Verify connection
\l
SELECT version();

plugins

developer-kit-java

skills

aws-rds-spring-boot-integration

references

advanced-configuration.md

troubleshooting.md

SKILL.md

README.md

tile.json