You can use a ConfigMap in a pod as follows:

  • Use a ConfigMap to define environment variables for a pod.
  • Use a ConfigMap to set command-line parameters.
  • Use a ConfigMap in volumes.

For more information, see Configure a Pod to Use a ConfigMap.

Limits

To use a ConfigMap in a pod, make sure that the ConfigMap and the pod are in the same cluster and namespace.

Create a ConfigMap

In this example, you create the special_config ConfigMap with two key-value pairs SPECIAL_LEVEL: very and SPECIAL_TYPE: charm.

Create a ConfigMap from an orchestration template

  1. Log on to the Container Service console.
  2. In the left-side navigation pane under Container Service - Kubernetes, choose Applications > Deployments. On the Deployments page that appears, click Create from Template in the upper-right corner.
  3. Select the cluster and namespace, select a sample template or Custom from the Sample Template drop-down list, and click Create.

    You can use the following YAML template to create a ConfigMap:

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

Create a ConfigMap on the web UI

  1. Log on to the Container Service console.
  2. In the left-side navigation pane under Container Service - Kubernetes, choose Configuration > ConfigMaps.
  3. On the ConfigMaps page that appears, select the cluster and namespace, and click Create in the upper-right corner.
  4. Enter the ConfigMap name. Click to add and configure key-value pairs. Then, click OK.

Use a ConfigMap to define environment variables for a pod

Use the values of a ConfigMap to define environment variables for a pod

  1. Log on to the Container Service console.
  2. In the left-side navigation pane under Container Service - Kubernetes, choose Applications > Deployments. On the Deployments page that appears, click Create from Template in the upper-right corner.
  3. Select the cluster and namespace, select a sample template or Custom from the Sample Template drop-down list, and click Create.

    You can define an environment variable for a pod by using valueFrom to reference the value of a key-value pair in a ConfigMap.

    The following sample template shows how to define an environment variable by referring the value of a key-value pair in a ConfigMap: 

    apiVersion: v1
kind: Pod
metadata:
   name: config-pod-1
spec:
   containers:
     - name: test-container
       image: busybox
       command: [ "/bin/sh", "-c", "env" ]
       env:
         - name: SPECIAL_LEVEL_KEY
           valueFrom:                             ## Specifies the key-value pair in the ConfigMap referenced by env.
             configMapKeyRef:
               name: special-config               ## The name of the referenced ConfigMap.
               key: SPECIAL_LEVEL                 ## The key of the referenced key-value pair.
   restartPolicy: Never

To define environment variables for a pod by using the values of multiple ConfigMaps, you only need to add multiple env parameters in the pod.

Configure all key-value pairs of a ConfigMap as the environment variables in a pod

  1. Log on to the Container Service console.
  2. In the left-side navigation pane under Container Service - Kubernetes, choose Applications > Deployments. On the Deployments page that appears, click Create from Template in the upper-right corner.
  3. Select the cluster and namespace, select a sample template or Custom from the Sample Template drop-down list, and click Create.

    If you need to configure all key-value pairs of a ConfigMap as the environment variables in a pod, use the envFrom parameter. The keys in the ConfigMap are used as the names of the environment variables.

    The following sample template shows how to configure all key-value pairs of a ConfigMap as the environment variables in a pod: 

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

Use a ConfigMap to set command-line parameters

  1. Log on to the Container Service console.
  2. In the left-side navigation pane under Container Service - Kubernetes, choose Applications > Deployments. On the Deployments page that appears, click Create from Template in the upper-right corner.
  3. Select the cluster and namespace, select a sample template or Custom from the Sample Template drop-down list, and click Create.

    You can use a ConfigMap to set command-line parameters for a container by using the environment variable replacement syntax $(VAR_NAME).

    The following sample template shows how to use a ConfigMap to set command-line parameters for a container. 

    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

    After the pod is run, the output is as follows:

    very charm

Use a ConfigMap in volumes

  1. Log on to the Container Service console.
  2. In the left-side navigation pane under Container Service - Kubernetes, choose Applications > Deployments. On the Deployments page that appears, click Create from Template in the upper-right corner.
  3. Select the cluster and namespace, select a sample template or Custom from the Sample Template drop-down list, and click Create.

    A ConfigMap can be used in volumes. You can specify the name of a ConfigMap under the volumes parameter. This stores the key-value pairs of the ConfigMap to the directory specified by mountPath, which is /etc/config in this example. This generates configuration files that are named after the keys of the ConfigMap. The corresponding values of the ConfigMap are stored in these files.

    The following sample template shows how to use a ConfigMap in volumes.

    apiVersion: v1
kind: Pod
metadata:
   name: config-pod-4
spec:
   containers:
     - name: test-container
       image: busybox
       command: [ "/bin/sh", "-c", "ls /etc/config/" ]   ## List the files in the directory.
       volumeMounts:
       - name: config-volume
         mountPath: /etc/config
   volumes:
     - name: config-volume
       configMap:
         name: special-config
   restartPolicy: Never

    After the pod is run, the output is as follows:

    SPECIAL_TYPE
SPECIAL_LEVEL