Use a config map in a pod

Limits

To use a config map in a pod, make sure the config map and the pod are in the same cluster and namespace.

Create a config map

In this example, create a config map special-config, which includes two key-value pairs: SPECIAL_LEVEL: very and SPECIAL_TYPE: charm.

Create a config map by using an orchestration template

1. Log on to the Container Service console.
2. Under Kubernetes, click Application > Deployment. Click Create by template in the upper-right corner.
3. Select the cluster and namespace from the Clusters and Namespace drop-down lists. Select a sample template or Custom from the Resource Type drop-down list. Click DEPLOY.

   You can use the following YAML sample template to create a config map.

   apiVersion: v1
   kind: ConfigMap
   metadata:
      name: special-config
      namespace: default
   data:
      SPECIAL_LEVEL: very
      SPECIAL_TYPE: charm

Create a config map on Config Maps page

1. Log on to the Container Service console.
2. Under Kubernetes, choose Configuration > Config Maps in the left-side navigation pane.
3. Select the cluster and namespace from the Clusters and Namespace drop-down lists. Click Create in the upper-right corner.
4. Enter a config map name, click the plus icon , set the name and value for each entry of the config map, and then click OK.

   
   
   

Use a config map to define pod environment variables

Use config map data to define pod environment variables

Similarly, to define the values of multiple config maps to the environment variable values of the pod, add multiple env parameters in the pod.

Configure all key-value pairs of a config map to pod environment variables

1. Log on to the Container Service console.
2. Under Kubernetes, click Application > Deployment. Click Create by template in the upper-right corner.
3. Select the cluster and namespace from the Clusters and Namespace drop-down lists. Select a sample template or Custom from the Resource Type drop-down list. Click DEPLOY.

   To configure all the key-value pairs of a config map to the environment variables of a pod, use the envFrom parameter. The key in a config map becomes the environment variable name in the pod.

   See the following orchestration example:

   apiVersion: v1
   kind: Pod
   metadata:
      name: config-pod-2
   spec:
      containers:
        - name: test-container
          image: busybox
          command: [ "/bin/sh", "-c", "env" ]
          envFrom:                ##Reference all the key-value pairs in the config map special-config.
          - configMapRef:
              name: special-config
      restartPolicy: Never

Use a config map to configure command line parameters

1. Log on to the Container Service console.
2. Under Kubernetes, click Application > Deployment . Click Create by template in the upper-right corner.
3. Select the cluster and namespace from the Clusters and Namespace drop-down lists. Select a sample template or Custom from the Resource Type drop-down list. Click DEPLOY.

   You can use the config map to configure the commands or parameter values in the container by using the environment variable replacement syntax $(VAR_NAME).

   See the following orchestration example:

   apiVersion: v1
   kind: Pod
   metadata:
      name: config-pod-3
   spec:
      containers:
        - name: test-container
          image: busybox
          command: [ "/bin/sh", "-c", "echo $(SPECIAL_LEVEL_KEY) $(SPECIAL_TYPE_KEY)" ]
          env:
            - name: SPECIAL_LEVEL_KEY
              valueFrom:
                configMapKeyRef:
                  name: special-config
                  key: SPECIAL_LEVEL
            - name: SPECIAL_TYPE_KEY
              valueFrom:
                configMapKeyRef:
                  name: special-config
                  key: SPECIAL_TYPE
      restartPolicy: Never

   The output after running the pod is as follows:

   very charm

Use a config map in data volumes