Exception on spring application startup with spring-cloud-kubernetes config maps dependencies present - spring-cloud

Question

I have a few spring services which has both Eureka-client and spring-cloud-starter-kubernetes-fabric8-all dependencies. By default, Eureka is enabled and Kubernetes is disabled.
management:
endpoints:
web:
exposure:
include: '*'
eureka:
client:
enabled: true
serviceUrl:
defaultZone: http://localhost:8080/eureka/
spring:
main:
banner-mode: off
application:
name: service-one
cloud:
kubernetes:
enabled: false
config:
enable-api: false
enabled: false
reload:
enabled: false
zipkin:
enabled: false
When I startup the app, I get the following exception as a warning, eventough kubernetes is disabled.
Running - docker run --rm dhananjay12/demo-service-one:latest
2021-05-02 23:35:51.458 INFO [,,] 1 --- [ main] ubernetesProfileEnvironmentPostProcessor : Did not find service account namespace at: [/var/run/secrets/kubernetes.io/serviceaccount/namespace]. Ignoring.
2021-05-02 23:35:51.464 WARN [,,] 1 --- [ main] ubernetesProfileEnvironmentPostProcessor : Not running inside kubernetes. Skipping 'kubernetes' profile activation.
2021-05-02 23:35:51.980 WARN [,,] 1 --- [ main] io.fabric8.kubernetes.client.Config : Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
2021-05-02 23:35:51.984 WARN [,,] 1 --- [ main] io.fabric8.kubernetes.client.Config : Error reading service account token from: [/var/run/secrets/kubernetes.io/serviceaccount/token]. Ignoring.
2021-05-02 23:35:51.987 WARN [,,] 1 --- [ main] o.s.c.k.f.Fabric8AutoConfiguration : No namespace has been detected. Please specify KUBERNETES_NAMESPACE env var, or use a later kubernetes version (1.3 or later)
2021-05-02 23:35:52.441 WARN [service-one,,] 1 --- [ main] s.c.k.f.c.Fabric8ConfigMapPropertySource : Can't read configMap with name: [service-one] in namespace:[null]. Ignoring.
io.fabric8.kubernetes.client.KubernetesClientException: Operation: [get] for kind: [ConfigMap] with name: [service-one] in namespace: [null] failed.
at io.fabric8.kubernetes.client.KubernetesClientException.launderThrowable(KubernetesClientException.java:64) ~[kubernetes-client-4.13.2.jar:na]
at io.fabric8.kubernetes.client.KubernetesClientException.launderThrowable(KubernetesClientException.java:72) ~[kubernetes-client-4.13.2.jar:na]
at io.fabric8.kubernetes.client.dsl.base.BaseOperation.getMandatory(BaseOperation.java:225) ~[kubernetes-client-4.13.2.jar:na]
at io.fabric8.kubernetes.client.dsl.base.BaseOperation.get(BaseOperation.java:186) ~[kubernetes-client-4.13.2.jar:na]
at io.fabric8.kubernetes.client.dsl.base.BaseOperation.get(BaseOperation.java:84) ~[kubernetes-client-4.13.2.jar:na]
at org.springframework.cloud.kubernetes.fabric8.config.Fabric8ConfigMapPropertySource.getData(Fabric8ConfigMapPropertySource.java:61) ~[spring-cloud-kubernetes-fabric8-config-2.0.2.jar:2.0.2]
at org.springframework.cloud.kubernetes.fabric8.config.Fabric8ConfigMapPropertySource.<init>(Fabric8ConfigMapPropertySource.java:50) ~[spring-cloud-kubernetes-fabric8-config-2.0.2.jar:2.0.2]
at org.springframework.cloud.kubernetes.fabric8.config.Fabric8ConfigMapPropertySourceLocator.getMapPropertySource(Fabric8ConfigMapPropertySourceLocator.java:51) ~[spring-cloud-kubernetes-fabric8-config-2.0.2.jar:2.0.2]
at org.springframework.cloud.kubernetes.commons.config.ConfigMapPropertySourceLocator.getMapPropertySourceForSingleConfigMap(ConfigMapPropertySourceLocator.java:81) ~[spring-cloud-kubernetes-commons-2.0.2.jar:2.0.2]
at org.springframework.cloud.kubernetes.commons.config.ConfigMapPropertySourceLocator.lambda$locate$0(ConfigMapPropertySourceLocator.java:67) ~[spring-cloud-kubernetes-commons-2.0.2.jar:2.0.2]
at java.base/java.util.Collections$SingletonList.forEach(Unknown Source) ~[na:na]
at org.springframework.cloud.kubernetes.commons.config.ConfigMapPropertySourceLocator.locate(ConfigMapPropertySourceLocator.java:67) ~[spring-cloud-kubernetes-commons-2.0.2.jar:2.0.2]
at org.springframework.cloud.bootstrap.config.PropertySourceLocator.locateCollection(PropertySourceLocator.java:51) ~[spring-cloud-context-3.0.2.jar:3.0.2]
at org.springframework.cloud.bootstrap.config.PropertySourceLocator.locateCollection(PropertySourceLocator.java:47) ~[spring-cloud-context-3.0.2.jar:3.0.2]
at org.springframework.cloud.bootstrap.config.PropertySourceBootstrapConfiguration.initialize(PropertySourceBootstrapConfiguration.java:95) ~[spring-cloud-context-3.0.2.jar:3.0.2]
at org.springframework.boot.SpringApplication.applyInitializers(SpringApplication.java:650) ~[spring-boot-2.4.5.jar:2.4.5]
at org.springframework.boot.SpringApplication.prepareContext(SpringApplication.java:403) ~[spring-boot-2.4.5.jar:2.4.5]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:338) ~[spring-boot-2.4.5.jar:2.4.5]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1340) ~[spring-boot-2.4.5.jar:2.4.5]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1329) ~[spring-boot-2.4.5.jar:2.4.5]
at com.mynotes.microservices.demo.serviceone.ServiceOneApplication.main(ServiceOneApplication.java:15) ~[classes/:na]
Caused by: java.net.UnknownHostException: kubernetes.default.svc: Name or service not known
The exception is not there if I put the same property in env variable.
Running - docker run --rm -e spring.cloud.kubernetes.config.enable-api=false dhananjay12/demo-service-one:latest
While the app does spin up and the rest of the thing works, can someone suggest, why is this exception there in the first place?
Code - https://github.com/dhananjay12/spring-microservice-demo/blob/master/service-one/src/main/resources/application.yml
Spring boot - 2.4.5, Spring cloud - 2020.0.2

Answer 1

On further analysis and going through the docs, disabling of these features must be set in bootstrap.yml - https://docs.spring.io/spring-cloud-kubernetes/docs/current/reference/html/index.html#kubernetes-ecosystem-awareness.
Of course env variable will have precedence