06-configmap.md

ConfigMap Example

Schritt 1: configmap vorbereiten

cd 
mkdir -p manifests 
cd manifests
mkdir configmaptests 
cd configmaptests
nano 01-configmap.yml

## 01-configmap.yml
kind: ConfigMap 
apiVersion: v1 
metadata:
  name: example-configmap 
data:
  # als Wertepaare
  database: mongodb
  database_uri: mongodb://localhost:27017

kubectl apply -f 01-configmap.yml 
kubectl get cm
kubectl get cm -o yaml

Schritt 2: Beispiel als Datei

nano 02-pod.yml

kind: Pod 
apiVersion: v1 
metadata:
  name: pod-mit-configmap 

spec:
  # Add the ConfigMap as a volume to the Pod
  volumes:
    # `name` here must match the name
    # specified in the volume mount
    - name: example-configmap-volume
      # Populate the volume with config map data
      configMap:
        # `name` here must match the name 
        # specified in the ConfigMap's YAML 
        name: example-configmap

  containers:
    - name: container-configmap
      image: nginx:latest
      # Mount the volume that contains the configuration data 
      # into your container filesystem
      volumeMounts:
        # `name` here must match the name
        # from the volumes section of this pod
        - name: example-configmap-volume
          mountPath: /etc/config

kubectl apply -f 02-pod.yml 

#Jetzt schauen wir uns den Container/Pod mal an
kubectl exec pod-mit-configmap -- ls -la /etc/config
kubectl exec -it pod-mit-configmap --  bash
# ls -la /etc/config 

Schritt 3: Beispiel. ConfigMap als env-variablen

nano 03-pod-mit-env.yml

# 03-pod-mit-env.yml 
kind: Pod 
apiVersion: v1 
metadata:
  name: pod-env-var 
spec:
  containers:
    - name: env-var-configmap
      image: nginx:latest 
      envFrom:
        - configMapRef:
            name: example-configmap

kubectl apply -f 03-pod-mit-env.yml

# und wir schauen uns das an 
#Jetzt schauen wir uns den Container/Pod mal an
kubectl exec pod-env-var -- env
kubectl exec -it pod-env-var --  bash
# env

Reference:

• https://matthewpalmer.net/kubernetes-app-developer/articles/ultimate-configmap-guide-kubernetes.html