Why does Consul try to connect to my database?

Question

I have a Spring Boot JPA application registering itself as a microservice with Consul:

@SpringBootApplication
@EnableDiscoveryClient
@EnableAutoConfiguration
public class Bootstrapper {

  public static void main(String[] args) {
      SpringApplication.run(Bootstrapper.class, args);
  }
}

My application.yml looks like this:

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/butler_test
    username: root
    password: pwd
    driver-class-name: com.mysql.jdbc.Driver
  jpa:
    hibernate:
      ddl-auto: create
    database-platform: org.hibernate.dialect.MySQL5InnoDBDialect
    show-sql: false

spring:
  cloud:
    consul:
      discovery:
        healthCheckPath: /health
        healthCheckInterval: 10s

However, when Consul contacts the /health endpoint, the following SQLException is thrown in my application:

"Host '172.17.0.1' is not allowed to connect to this MySQL server".

What is going on and why is there even a connection attempt?

Answer 1

When you have a datasource configured, the health check endpoint will ping the database by default by doing a SELECT 1 to make sure the connection to the database is working. If it is, it will display the status as "UP". Since you are seeing the error, your database configuration is probably incorrect.

You can disable the datasource health check by configuring it in your properties: management.health.db.enabled=false

If you would like to configure the check, see here: Spring Boot Actuator Health Indicator