Why spring boot application constantly fetch configuration from config service? - spring-boot

Question

I'm building microservices using Spring Boot & Spring Cloud Config. From the log file, I can see one of my application send a request to config service for configuration every five minutes while other applications do not play the same behaviour.
06:04:28.586 [serviceId:xxx-service/traceId:545d584f10da3123/spanId:545d584f10da3123/parentId:] INFO o.s.c.c.c.ConfigServicePropertySourceLocator.getRemoteEnvironment - Fetching config from server at : http://config-service
06:04:30.135 [serviceId:xxx-service/traceId:545d584f10da3123/spanId:545d584f10da3123/parentId:] INFO o.s.c.c.c.ConfigServicePropertySourceLocator.log - Located environment: name=xxxservice, profiles=[dev], label=master, version=00ed4aebcd466c88b4a7df61296652944642cdc8, state=null
06:09:30.367 [serviceId:xxx-service/traceId:519fdde3a2d8ce5a/spanId:519fdde3a2d8ce5a/parentId:] INFO o.s.c.c.c.ConfigServicePropertySourceLocator.getRemoteEnvironment - Fetching config from server at : http://config-service
06:09:31.928 [serviceId:xxx-service/traceId:519fdde3a2d8ce5a/spanId:519fdde3a2d8ce5a/parentId:] INFO o.s.c.c.c.ConfigServicePropertySourceLocator.log - Located environment: name=xxxservice, profiles=[dev], label=master, version=00ed4aebcd466c88b4a7df61296652944642cdc8, state=null
06:14:32.035 [serviceId:xxx-service/traceId:e32c45c3a5c3fcca/spanId:e32c45c3a5c3fcca/parentId:] INFO o.s.c.c.c.ConfigServicePropertySourceLocator.getRemoteEnvironment - Fetching config from server at : http://config-service
06:14:33.611 [serviceId:xxx-service/traceId:e32c45c3a5c3fcca/spanId:e32c45c3a5c3fcca/parentId:] INFO o.s.c.c.c.ConfigServicePropertySourceLocator.log - Located environment: name=xxxservice, profiles=[dev], label=master, version=00ed4aebcd466c88b4a7df61296652944642cdc8, state=null
06:19:32.033 [serviceId:xxx-service/traceId:16fc982b0638d4a6/spanId:16fc982b0638d4a6/parentId:] INFO o.s.c.c.c.ConfigServicePropertySourceLocator.getRemoteEnvironment - Fetching config from server at : http://config-service
06:19:33.495 [serviceId:xxx-service/traceId:16fc982b0638d4a6/spanId:16fc982b0638d4a6/parentId:] INFO o.s.c.c.c.ConfigServicePropertySourceLocator.log - Located environment: name=xxxservice, profiles=[dev], label=master, version=00ed4aebcd466c88b4a7df61296652944642cdc8, state=null
06:24:32.036 [serviceId:xxx-service/traceId:f4eae364e2624d58/spanId:f4eae364e2624d58/parentId:] INFO o.s.c.c.c.ConfigServicePropertySourceLocator.getRemoteEnvironment - Fetching config from server at : http://config-service
06:24:33.640 [serviceId:xxx-service/traceId:f4eae364e2624d58/spanId:f4eae364e2624d58/parentId:] INFO o.s.c.c.c.ConfigServicePropertySourceLocator.log - Located environment: name=xxxservice, profiles=[dev], label=master, version=00ed4aebcd466c88b4a7df61296652944642cdc8, state=null
I try to understand this behaviour.
1 Is the bootstrap.yml of this service distinct to other services, leads the unique behaviour?
No, all services bootstrap.yml appear to be the same structure without different config keys:
spring:
profiles:
active: dev
cloud:
config:
name: xxxservice
label: master
uri: http://config-service
2 Is this servie trying to refresh its configuration dynamicly and periodly?
No, in order to dynamically refresh the configuration of a spring boot application, we need to:
put the #RefreshScope annotation on the class reading configuration
call with something like curl -X POST http://xx:8080/refresh to trigger refresh manually
So there should not be auto refresh behaviour periodly.
The question remaining unresolved, hope someone explain this situation directly or point any error in my statement.

Answer 1

I don't know why you are not seeing this with other services, but I believe that this behavior is due to the client wanting to check the health of the server periodically. From the Spring Cloud Config Client docs:
7.8.1 Health Indicator
The Config Client supplies a Spring Boot Health Indicator that attempts to load configuration from the Config Server. The health
indicator can be disabled by setting health.config.enabled=false.
The response is also cached for performance reasons. The default cache
time to live is 5 minutes. To change that value, set the
health.config.time-to-live property (in milliseconds).
So just set health.config.enabled=false, and this behavior should stop.