Handling Password Rotation in Spring Cloud Stream Consumers Connected to MSK Kafka
Problem: When your Spring Cloud Stream applications consume messages from Amazon Managed Streaming for Kafka (MSK), you face the challenge of gracefully handling password rotation. This situation arises when the MSK cluster's credentials change, potentially due to security policy updates or scheduled password refreshes. If not handled appropriately, your application's connection to MSK will be disrupted, leading to message ingestion failures and service interruptions.
Simplified Explanation: Imagine your application needs a key to open a locked box (MSK cluster) to read messages. The key (password) is changed periodically. If your application doesn't update the key, it won't be able to open the box and read messages anymore.
Scenario and Original Code:
Let's assume a Spring Cloud Stream application consuming messages from MSK using the kafka binder:
@SpringBootApplication
public class ConsumerApplication {
public static void main(String[] args) {
SpringApplication.run(ConsumerApplication.class, args);
}
@Bean
public ConsumerConfig consumerConfig() {
Map<String, Object> props = new HashMap<>();
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, "your-msk-cluster-endpoint");
props.put(ConsumerConfig.GROUP_ID_CONFIG, "your-consumer-group");
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.SECURITY_PROTOCOL_CONFIG, "SASL_SSL");
props.put(SaslConfig.SASL_MECHANISM, "PLAIN");
props.put(SaslConfig.SASL_JAAS_CONFIG, "org.apache.kafka.common.security.plain.PlainLoginModule required username=\"your-user\" password=\"your-password\";");
return new ConsumerConfig(props);
}
}
Insights and Analysis:
The code snippet above uses hardcoded credentials, which poses a security risk and fails to handle password rotation. When the MSK password changes, the application won't be able to connect, leading to broken functionality. Here are some solutions:
- External Configuration: Store the credentials in a secure external configuration source like Vault or AWS Secrets Manager. Update the configuration source whenever the password changes. Your application can then dynamically retrieve updated credentials.
- Dynamic Configuration with Spring Cloud Config: Use Spring Cloud Config to manage your configuration. This allows for easy updating of credentials via the Config Server.
- Spring Cloud Stream Kafka Binder Properties: Leverage the Spring Cloud Stream Kafka binder's
spring.cloud.stream.kafka.binder.brokersandspring.cloud.stream.kafka.binder.sasl.jaas.configproperties to dynamically load credentials at runtime. This allows you to manage password changes through environment variables or external configuration.
Example: Spring Cloud Config for Dynamic Password Updates
- Configure a Spring Cloud Config Server: Set up a Config Server, for example, using Spring Boot, to manage configuration properties.
- Store Credentials in the Config Server: Define a property source in the Config Server for your MSK credentials.
- Configure Spring Cloud Stream to Use Config Server: Configure your Spring Cloud Stream application to connect to the Config Server and retrieve the updated credentials.
Code Example:
@SpringBootApplication
@EnableConfigServer
public class ConfigServerApplication {
public static void main(String[] args) {
SpringApplication.run(ConfigServerApplication.class, args);
}
}
// Consumer Application with Spring Cloud Config
@SpringBootApplication
@EnableConfigServer
public class ConsumerApplication {
public static void main(String[] args) {
SpringApplication.run(ConsumerApplication.class, args);
}
@Bean
public ConsumerConfig consumerConfig(@Value("${spring.cloud.stream.kafka.binder.brokers}") String brokers,
@Value("${spring.cloud.stream.kafka.binder.sasl.jaas.config}") String jaasConfig) {
Map<String, Object> props = new HashMap<>();
props.put(ConsumerConfig.BOOTSTRAP_SERVERS_CONFIG, brokers);
props.put(ConsumerConfig.GROUP_ID_CONFIG, "your-consumer-group");
props.put(ConsumerConfig.KEY_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.VALUE_DESERIALIZER_CLASS_CONFIG, StringDeserializer.class);
props.put(ConsumerConfig.SECURITY_PROTOCOL_CONFIG, "SASL_SSL");
props.put(SaslConfig.SASL_MECHANISM, "PLAIN");
props.put(SaslConfig.SASL_JAAS_CONFIG, jaasConfig);
return new ConsumerConfig(props);
}
}
Additional Value:
- Best Practices: Always prioritize secure credential management techniques like external configuration or dedicated secrets management services. Avoid hardcoding credentials directly in your code.
- Monitoring and Alerting: Set up monitoring to track password changes and ensure your application is successfully pulling credentials updates. Implement alerts to notify you of any connection errors or failures to retrieve updated credentials.
References and Resources:
By implementing these strategies, you can ensure your Spring Cloud Stream applications connected to MSK gracefully handle password rotations, preventing service interruptions and maintaining reliable message processing.
