java - Cannot read configmap with name: [xx] in namespace ['default'] Ignoring

Question

New to k8s.

Trying to read values from profile based config map. My configmap exists in default namespace. But, spring boot is not pickingup the values.

Config map looks like:

apiVersion: v1
kind: ConfigMap
metadata:
    name: example-configmap-overriding-new-01
data:
    application.properties: |-
        globalkey = global key value
    application-qa.properties: |-
        globalkey = global key qa value    
    application-prod.properties: |-
        globalkey = global key prod value

The config map is created in default namespace too.

kubectl get configmap -n default 

NAME                                  DATA   AGE
example-configmap-overriding-new-01   3      8d

My deployment file looks like

apiVersion: apps/v1
kind: Deployment
metadata: 
    name: demo-configmapk8testing
spec:  
    selector:
        matchLabels:
            app: demo-configmapk8testing
replicas: 1
template: 
    metadata:
        labels:
            app: demo-configmapk8testing        
    spec:
        containers:
          - name: demo-configmapk8testing
            image: Path to image
            ports:
            - containerPort: 8080
            args: [
            "--spring.profiles.active=prod",
            "--spring.application.name=example-configmap-overriding-new-01",
            "--spring.cloud.kubernetes.config.name=example-configmap-
            overriding-new-01",
            "--spring.cloud.kubernetes.config.namespace=default",
            "--spring.cloud.kubernetes.config.enabled=true"]
            envFrom:
            - configMapRef:
                name: example-configmap-overriding-new-01

But the spring boot log says:-

2019-07-02 22:10:38.092  WARN 1 --- [           main] 
o.s.c.k.config.ConfigMapPropertySource   : Can't read configMap with name: 
[example-configmap-overriding-new-01] in namespace:[default]. Ignoring

2019-07-02 22:10:38.331  INFO 1 --- [           main] 
b.c.PropertySourceBootstrapConfiguration : Located property source: 
CompositePropertySource {name='composite-configmap', propertySources= 
[ConfigMapPropertySource {name='configmap.example-configmap-overriding-new- 
01.default'}]}

2019-07-02 22:10:38.420  INFO 1 --- [           main] 
b.c.PropertySourceBootstrapConfiguration : Located property source: 
SecretsPropertySource {name='secrets.example-configmap-overriding-new- 
01.default'}

2019-07-02 22:10:38.692  INFO 1 --- [           main] 
c.e.c.ConfigconsumerApplication          : **The following profiles are 
active: prod**

--some logs--

Injection of autowired dependencies failed; nested exception is 
java.lang.IllegalArgumentException: **Could not resolve placeholder 
'globalkey' in value "${globalkey}"**

My spring boot config file looks like

@Configuration
public class ConfigConsumerConfig {

    @Value(value = "${globalkey}")
    private String globalkey;

    // with getter and setters 
}

My pom.xml has the following dependency too.

    <dependency>
        <groupId>org.springframework.cloud</groupId>
        <artifactId>spring-cloud-starter-kubernetes-config</artifactId>
        <version>1.0.2.RELEASE</version>
    </dependency>

    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-configuration-processor</artifactId>
        <optional>true</optional>
    </dependency>

I am running minikube in my local machine. Am I missing something here?

Could someone share some inputs here.

Answer 1

spring-cloud-kubernetes doesn't have access to the Kubernetes API so it can't read the configMap. Check this docs for more details: https://github.com/spring-cloud/spring-cloud-kubernetes/blob/master/docs/src/main/asciidoc/security-service-accounts.adoc.

In short, apply this configuration and it will work fine:

kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  namespace: YOUR-NAME-SPACE
  name: namespace-reader
rules:
  - apiGroups: ["", "extensions", "apps"]
    resources: ["configmaps", "pods", "services", "endpoints", "secrets"]
    verbs: ["get", "list", "watch"]

---

kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: namespace-reader-binding
  namespace: YOUR-NAME-SPACE
subjects:
- kind: ServiceAccount
  name: default
  apiGroup: ""
roleRef:
  kind: Role
  name: namespace-reader
  apiGroup: ""

You can read about Roles and RoleBinding in more detail here: https://kubernetes.io/docs/reference/access-authn-authz/rbac/.

Note: You don't have to create volumes and volume mounts. I would say it is an alternative for it. If you would like to have it this way then you have to specify spring.cloud.kubernetes.config.paths in the spring boot application configuration (I have written it into bootstrap.yaml resource file). E.g.

spring: 
  cloud:
    kubernetes:
      config:
        paths: /etc/config/application.yaml

And then via Kubernetes Deployment configuration create ConfigMap volume and mount it on that path. In our example the path would be /etc/config.

Let me know if it works for you :)