Configuring Environment Variables

Before using a ConfigMap or secret as an environment variable, ensure that the ConfigMap and secret have been created in the cluster. For details about how to create a ConfigMap and secret, see Creating a ConfigMap and Creating a Secret.

1. Log in to the CCE console and click the cluster name to access the cluster console. In the navigation pane, choose Workloads. In the upper right corner, click Create Workload.
2. In Container Information (Container Settings > Container Information), choose Environment Variables.
3. Configure environment variables as needed. CCE clusters support multiple types of environment variables. For details, see Table 1.
   • To add environment variables one by one, click Add Variable and set Type, Variable Name, and Variable Value/Reference.
   • To add environment variables in batches, click Batch Edit Custom Variables. Then, in the displayed dialog box, enter environment variables in the format of "Variable name=Variable value or variable reference".
   Figure 1 Configuring environment variables
   

   Table 1 Environment variables

   Parameter	Description
   Type	Environment variable type. The options are as follows: Custom: Enter the environment variable name and value. Added from ConfigMap: Import all key values in a ConfigMap as environment variables. As shown in Figure 1, all key values in configmap-example are imported as environment variables. Added from ConfigMap key: Import a key value in a ConfigMap as the value of an environment variable. As shown in Figure 1, the value of configmap_key in configmap-example is imported as the value of the environment variable. If the value of configmap_key is configmap_value, the value of key1 is configmap_value. Added from secret: Import all key values in a secret as environment variables. As shown in Figure 1, all key values in secret-example are imported as environment variables. Added from secret key: Import the value of a key in a secret as the value of an environment variable. As shown in Figure 1, the value of secret_key in secret-example is imported as the environment variable. If the value of secret_key is secret_value, the value of key2 is secret_value. Variable Value/Reference: Use the field defined by a pod as the value of the environment variable. As shown in Figure 1, the pod name is imported as the value of key3. Resource Reference: The value of Request or Limit defined by the container is used as the value of the environment variable. As shown in Figure 1, the CPU limit of container-1 is imported as the value of key4.
   Variable Name	Name of the environment variable set in the container.
   Variable Value/Reference	The value of an environment variable or the value of an environment variable obtained from other sources.

4. Configure other parameters and click Create Workload in the lower right corner. After a period of time, the workload status changes to Running.

Assume that a ConfigMap and a secret are already available in the cluster. For details about how to create them, see Creating a ConfigMap and Creating a Secret.

1. Use kubectl to access the cluster. For details, see Connecting to a Cluster Using kubectl.
2. Check the ConfigMap in the cluster. In this example, the ConfigMap is named configmap-example.

   kubectl get configmap configmap-example -oyaml

   Information similar to the following is displayed:

   apiVersion: v1
   data:
     configmap_key: configmap_value
   kind: ConfigMap
   ...

3. Check the secret in the cluster. In this example, the secret is named secret-example.

   kubectl get secret secret-example -oyaml

   Information similar to the following is displayed:

   apiVersion: v1
   data:
     secret_key: c2VjcmV0X3ZhbHVl              # c2VjcmV0X3ZhbHVl is the value of secret_value in Base64 mode.
   kind: Secret
   ...

4. Create a file named nginx-deployment.yaml. nginx-deployment.yaml is an example file name, and you can rename it as needed.

   vi nginx-deployment.yaml

   Configure environment variables in the workload YAML file. The following is an example:

   apiVersion: apps/v1
   kind: Deployment
   metadata:
     name: env-example
     namespace: default
   spec:
     replicas: 1
     selector:
       matchLabels:
         app: env-example
     template:
       metadata:
         labels:
           app: env-example
       spec:
         containers:
           - name: container-1
             image: nginx:alpine
             imagePullPolicy: Always
             resources:
               requests:
                 cpu: 250m
                 memory: 512Mi
               limits:
                 cpu: 250m
                 memory: 512Mi
             env:
               - name: key                     # Define the environment variable name and value.
                 value: value
               - name: key1                    # Import the value of a key in the ConfigMap as the value of an environment variable.
                 valueFrom:
                   configMapKeyRef:
                     name: configmap-example
                     key: configmap_key
               - name: key2                    # Import the value of a key in the secret as the value of an environment variable.
                 valueFrom:
                   secretKeyRef:
                     name: secret-example
                     key: secret_key
               - name: key3                    # Use the field defined by the pod as the value of an environment variable.
                 valueFrom:
                   fieldRef:
                     apiVersion: v1
                     fieldPath: metadata.name
               - name: key4                    # Use the value of the resource request or limit defined in the container as the value of an environment variable.
                 valueFrom:
                   resourceFieldRef:
                     containerName: container1
                     resource: limits.cpu
                     divisor: 1
             envFrom:
               - configMapRef:                 # Import all key values in a ConfigMap as environment variables.
                   name: configmap-example
               - secretRef:                    # Import all key values in a secret as environment variables.
                   name: secret-example
         imagePullSecrets:
           - name: default-secret

5. Create the Deployment.

   kubectl create -f nginx-deployment.yaml

   If information similar to the following is displayed, the workload is being created:

   deployment.apps/env-example created

6. Check the pod name.

   kubectl get pod

   Information similar to the following is displayed:

   NAME                           READY   STATUS    RESTARTS   AGE
   env-example-695b759569-lx9jp   1/1     Running   0          17m

7. View environment variables in the pod.

   kubectl exec env-example-695b759569-lx9jp  -- printenv

   If information similar to the following is displayed, the environment variables are configured successfully:

   / # env
   key=value                             # Custom environment variable
   key1=configmap_value                  # Added from a ConfigMap key
   key2=secret_value                     # Added from a secret key
   key3=env-example-695b759569-lx9jp     # metadata.name defined by the pod
   key4=1                                # limits.cpu defined by container1. The value is rounded up, in unit of cores.
   configmap_key=configmap_value         # Added from a ConfigMap. The key value in the original ConfigMap key is imported.
   secret_key=secret_value               # Added from a secret. The key value in the original secret is imported.