Can I consume a ConfigMap value in arbitrary places in YAML?-CodePudding

In Azure Kubernetes Service, my goal is to configure both staging and production k8 clusters with a common YAML file, with critical values & environment variables parameterized from a ConfigMap.

I can set container environment variables easily using valueFrom but I would like to use the ConfigMap values in other areas of the YAML file, for example:

staging-config-map.yaml:

kind: ConfigMap 
apiVersion: v1 
metadata:
  name: base-config 
data:
  ENVIRONMENT_NAME: staging
  ...

prod-config-map.yaml:

kind: ConfigMap 
apiVersion: v1 
metadata:
  name: base-config 
data:
  ENVIRONMENT_NAME: prod
  ...

common-cluster-config.yaml:

apiVersion: v1
kind: Service
metadata:
  name: my-amazing-microservice
  annotations:
    service.beta.kubernetes.io/azure-dns-label-name: "my-amazing-microservice-$ENVIRONMENT_NAME"
spec:
  type: LoadBalancer
  ports:
  - targetPort: 5000
    name: port5000
    port: 5000
    protocol: TCP
  selector:
    app: my-amazing-microservice
---
...

Note the reference to $ENVIRONMENT_NAME which is where I want to insert something from the ConfigMap.

Can I do this, so I don't have to maintain duplicated manifests for staging and prod?

CodePudding user response：

No you cant with vanilla k8's manifests. ConfigMaps are just resources that get mounted into the container when it starts. Either as env variables or as a file. You cant access a config map at deployment time.

I suggest looking into helm that can do this with templating.