> ## Documentation Index > Fetch the complete documentation index at: https://notes.kodekloud.com/llms.txt > Use this file to discover all available pages before exploring further. # Solution Env Variables Optional > Learn to manage environment variables in Kubernetes pods and update them using direct modifications and ConfigMaps for dynamic configuration. In this lab, you'll learn how to manage environment variables in a Kubernetes pod and update them using both direct modifications and ConfigMaps. Follow along to understand how to check running pods, update environment variables, and integrate ConfigMaps for dynamic configuration. ## Checking the Running Pod First, check how many pods are currently running. In this example, we're working with a single pod named "webapp-color": ```bash theme={null} k get pods ``` Output: ```bash theme={null} NAME READY STATUS RESTARTS AGE webapp-color 1/1 Running 0 16s ``` Next, inspect the pod details to identify the configured environment variables. Look for the `APP_COLOR` variable, which in this case is set to `pink`: ```bash theme={null} Image ID: docker.io/kodekloud/webapp-color@sha256:99c3821ea49b89c7a22d3eebabab5c2e1ec651452e7675 Port: Host Port: State: Running Started: Sat, 16 Apr 2022 22:49:49 +0000 Ready: True Restart Count: 0 Environment: APP_COLOR: pink ... ``` When you access the web application via the provided link, you'll notice that the background color is pink. ## Updating the Pod to Change the Environment Variable To change the background color of the web application, update the `APP_COLOR` environment variable. Start by editing the pod manifest using: ```bash theme={null} kubectl edit pod webapp-color ``` Pods are immutable, so while you can edit a pod's manifest, the changes cannot be applied directly. Instead, save the modified manifest locally and force replace the pod. Below is an excerpt from the downloaded manifest where the `APP_COLOR` value is updated to `"green"`: ```yaml theme={null} apiVersion: v1 kind: Pod metadata: creationTimestamp: "2022-04-16T22:49:43Z" labels: name: webapp-color name: webapp-color namespace: default resourceVersion: "874" uid: 4f24d49d-04cc-4617-88b0-8478ca19a203 spec: containers: - env: - name: APP_COLOR value: green image: kodekloud/webapp-color imagePullPolicy: Always name: webapp-color resources: {} terminationMessagePath: /dev/termination-log terminationMessagePolicy: File volumeMounts: - mountPath: /var/run/secrets/kubernetes.io/serviceaccount name: kube-api-access-2nbfl readOnly: true dnsPolicy: ClusterFirst enableServiceLinks: true nodeName: controlplane preemptionPolicy: PreemptLowerPriority priority: 0 restartPolicy: Always schedulerName: default-scheduler securityContext: {} serviceAccount: default serviceAccountName: default ``` Save your changes. If you receive an error stating that editing pods is forbidden due to immutability, don't worry—the manifest is stored (e.g., in `/tmp/kubectl-edit-3135302771.yaml`). Force replace the existing pod with the updated manifest: ```bash theme={null} kubectl replace --force -f /tmp/kubectl-edit-3135302771.yaml ``` You should see the following confirmation: ```bash theme={null} pod "webapp-color" deleted pod/webapp-color replaced ``` After the pod is recreated, verify that the change has taken effect: ```bash theme={null} kubectl describe pod webapp-color ``` The output will now reflect that the environment variable `APP_COLOR` is set to `green`, and the web application's background should display green. ## Working with ConfigMaps In addition to direct environment variable updates, Kubernetes supports managing configurations with ConfigMaps. This provides a dynamic way to update environment variables for your pods. ### Listing Existing ConfigMaps To see the current ConfigMaps in the default namespace, run: ```bash theme={null} kubectl get configmap ``` Output: ```bash theme={null} NAME DATA AGE kube-root-ca.crt 1 16m db-config 3 22s ``` ### Inspecting a Specific ConfigMap To check the database host specified in the `db-config` ConfigMap, describe it: ```bash theme={null} kubectl describe cm db-config ``` The description will include: ```bash theme={null} Name: db-config Namespace: default Labels: Annotations: Data ==== DB_HOST: SQL01.example.com DB_NAME: SQL01 DB_PORT: 3306 BinaryData ========== Events: ``` This shows that the `DB_HOST` is set to `SQL01.example.com`. ### Creating a New ConfigMap for the Web Application For the web application pod, we want to use a ConfigMap to set the environment variable dynamically. Create a new ConfigMap that sets `APP_COLOR` to `dark blue`: ```bash theme={null} kubectl create configmap webapp-config-map --from-literal=APP_COLOR="dark blue" ``` This command creates a ConfigMap named `webapp-config-map` containing the desired environment variable. ### Updating the Pod to Use the New ConfigMap Next, update the pod manifest so that the web application retrieves its environment variables from the ConfigMap instead of a static declaration. Modify the manifest to remove the direct `env` key and add an `envFrom` reference: ```yaml theme={null} apiVersion: v1 kind: Pod metadata: creationTimestamp: "2022-04-16T22:52:40Z" labels: name: webapp-color name: webapp-color namespace: default resourceVersion: "929" uid: f17244ec-f17f-4027-9f6c-58aa47f2cf03 spec: containers: - envFrom: - configMapRef: name: webapp-config-map image: kodekloud/webapp-color imagePullPolicy: Always name: webapp-color resources: {} terminationMessagePath: /dev/termination-log terminationMessagePolicy: File volumeMounts: - mountPath: /var/run/secrets/kubernetes.io/serviceaccount name: kube-api-access-2nbfl readOnly: true dnsPolicy: ClusterFirst enableServiceLinks: true nodeName: controlplane preemptionPolicy: PreemptLowerPriority priority: 0 restartPolicy: Always schedulerName: default-scheduler securityContext: {} serviceAccount: default serviceAccountName: default ``` Save your updated manifest and force replace the pod by running: ```bash theme={null} kubectl replace --force -f /tmp/kubectl-edit-192529677.yaml ``` You will see confirmation messages: ```bash theme={null} pod "webapp-color" deleted pod/webapp-color replaced ``` Finally, verify the update: ```bash theme={null} kubectl describe pod webapp-color ``` The pod description now shows that it sources its `APP_COLOR` environment variable from the `webapp-config-map` ConfigMap. When you access the web application, the background color will have changed to dark blue. In this lab, you learned how to update environment variables both directly in a pod manifest and dynamically using ConfigMaps. These skills are essential for managing application configurations in Kubernetes. Explore more about managing configurations in Kubernetes by visiting the [Kubernetes Documentation](https://kubernetes.io/docs/).