Kubernetes - ConfigMaps and Secrets [Part 10]

 

ConfigMaps are used to provide the configuration information for the workloads.  This can either be fine-grained string format or file format.

Secrets: It is similar like ConfigMaps but it will provide the sensitive information into workloads.

Created a ConfigMaps file:

ConfigMaps can be mount as file system in the Pod and passing a environmental variables or passing a ConfigMaps through command line from the K8S.

Created a Yaml file for mounting the ConfigMaps as file system inside of the pod.

apiVersion: v1

kind: Pod

metadata:

  name: kuard-config

spec:

  containers:

    - name: test-container

      image: gcr.io/kuar-demo/kuard-amd64:blue

      imagePullPolicy: Always

      command:

        - "/kuard"

        - "$(EXTRA_PARAM)"

      env:

        - name: ANOTHER_PARAM

          valueFrom:

            configMapKeyRef:

              name: my-config

              key: another-param

        - name: EXTRA_PARAM

          valueFrom:

            configMapKeyRef:

              name: my-config

              key: extra-param

      volumeMounts:

        - name: config-volume

          mountPath: /config

  volumes:

    - name: config-volume

      configMap:

        name: my-config

  restartPolicy: Never

Secrets:

Secrets used to managing passwords, security tokens, other type of private keys.  Secrets are exposed to Pods via explicit declaration in the Pod manifests and Kubernetes API. Secrets are stored in the tmpfs file system [RAM disk].

Defined the Secrets inside the Pod configuration:

apiVersion: v1

kind: Pod

metadata:

  name: kuard-tls

spec:

  containers:

    - name: kuard-tls

      image: gcr.io/kuar-demo/kuard-amd64:blue

      imagePullPolicy: Always

      volumeMounts:

      - name: tls-certs

        mountPath: "/tls"

        readOnly: true

  volumes:

    - name: tls-certs

      secret:

        secretName: kuard-tls

Created a secrets for the docker pull registry:

# kubectl create secret docker-registry my-image-pull-secret --docker-username=<username> --docker-password=<password> --docker-email=<email-address>

Updating the ConfigMap or Secrets file:

#kubectl replace -f filename

(or)

Edit the configuration file through command line

$ kubectl edit configmap my-config