Kubernetes/ConfigMap and Secrets

ConfigMap object allows to manage application's configuration using Kubernetes primitives. YAML below:

kubectl create configmap my-config-map --namespace=web -oyaml --dry-run > config-map.yml

<syntaxhighlightjs lang=yaml> apiVersion: v1 kind: ConfigMap metadata:

 creationTimestamp: null
 name: my-config-map
 namespace: web

data: # added when editing

 myKey: myValue1
 anotherKey: myValue2

</syntaxhighlightjs>

ConfigMap

As a environment	Mounted volume	Secrets mounted volume
<syntaxhighlightjs lang=yaml> apiVersion: v1 kind: Pod metadata: name: configmap-kube spec: containers: - name: nginx image: nginx command: ['sh', '-c', "echo $(VAR) && sleep 600"] env: - name: VAR valueFrom: configMapKeyRef: name: kubeapp-config key: value1 </syntaxhighlightjs>	<syntaxhighlightjs lang=yaml>apiVersion: v1 kind: Pod metadata: name: configmap-volume-kube spec: containers: - name: nginx image: nginx command: ['sh', '-c', "echo $(cat /etc/config/myKey && sleep 3600"] volumeMounts: - name: configmapvolume mountPath: /etc/config # this will be a directory volumes: - name: configmapvolume configMap: # key will be a file name name: kubeapp-config # with value in content </syntaxhighlightjs>	<syntaxhighlightjs lang=yaml> apiVersion: v1 kind: Pod metadata: name: kube-secret-volume-pod spec: containers: - name: nginx image: nginx command: ['sh', '-c', "echo $(MY_VAR) && sleep 3600"] volumeMounts: - name: secretvolume mountPath: /etc/certs volumes: - name: secretvolume secret: secretName: kube-secret </syntaxhighlightjs>

Deploy

kubectl apply -f configmap-pod.yaml
kubectl logs configmap-pod         #Get the logs from the pod displaying the value

Another way to provide values from a ConfigMap is to mount as a container's volume. The keys you can see within the container

kubectl exec configmaps-volume-kube -- ls  /etc/config
kubectl exec configmaps-volume-kube -- cat /etc/config/key1

The YAML for a secret: <syntaxhighlightjs lang=yaml> apiVersion: v1 kind: Secret metadata:

 name: kube-secret

stringData:

 cert: 1234abc
 key: ca.crt

</syntaxhighlightjs>

Create secrets

kubectl apply -f secrets.yaml
kubectl describe secrets appsecret 
Name:         kube-secret
Namespace:    default
Labels:       <none>
Annotations:  
Type:         Opaque

Data
====
cert:  5 bytes
key:   5 bytes

References

• configure-pod-configmap
• Secretes