ConfigMap example

Step Zero: Prerequisites

This example assumes you have a Kubernetes cluster installed and running, and that you have installed the kubectl command line tool somewhere in your path. Please see pick the right solution started for installation instructions for your platform.

Step One: Create the ConfigMap

A ConfigMap contains a set of named strings.

Use the configmap.yaml file to create a ConfigMap:

$ kubectl create -f docs/user-guide/configmap/configmap.yaml

You can use kubectl to see information about the ConfigMap:

$ kubectl get configmap
NAME                   DATA      AGE
test-configmap         2         6s

$ kubectl describe configMap test-configmap
Name:          test-configmap
Labels:        <none>
Annotations:   <none>

Data
====
data-1: 7 bytes
data-2: 7 bytes

View the values of the keys with kubectl get:

$ kubectl get configmaps test-configmap -o yaml
apiVersion: v1
data:
  data-1: value-1
  data-2: value-2
kind: ConfigMap
metadata:
  creationTimestamp: 2016-02-18T20:28:50Z
  name: test-configmap
  namespace: default
  resourceVersion: "1090"
  selfLink: /api/v1/namespaces/default/configmaps/test-configmap
  uid: 384bd365-d67e-11e5-8cd0-68f728db1985

Step Two: Create a pod that consumes a configMap in environment variables

Use the env-pod.yaml file to create a Pod that consumes the ConfigMap in environment variables.

$ kubectl create -f docs/user-guide/configmap/env-pod.yaml

This pod runs the env command to display the environment of the container:

$ kubectl logs config-env-test-pod | grep KUBE_CONFIG
KUBE_CONFIG_1=value-1
KUBE_CONFIG_2=value-2

Step Three: Create a pod that sets the command line using ConfigMap

Use the command-pod.yaml file to create a Pod with a container whose command is injected with the keys of a ConfigMap

$ kubectl create -f docs/user-guide/configmap/command-pod.yaml

This pod runs an echo command to display the keys:

$ kubectl logs config-cmd-test-pod
value-1 value-2

Step Four: Create a pod that consumes a configMap in a volume

Pods can also consume ConfigMaps in volumes. Use the volume-pod.yaml file to create a Pod that consume the ConfigMap in a volume.

$ kubectl create -f docs/user-guide/configmap/volume-pod.yaml

This pod runs a cat command to print the value of one of the keys in the volume:

$ kubectl logs config-volume-test-pod
value-1

Alternatively you can use mount-file-pod.yaml file to mount only a file from ConfigMap, preserving original content of /etc directory.

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