Add French configure-pod-configmap
Rémy Léone
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---
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title: Configure a Pod to Use a ConfigMap
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content_template: templates/task
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weight: 150
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card:
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name: tasks
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weight: 50
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---
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{{% capture overview %}}
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ConfigMaps allow you to decouple configuration artifacts from image content to keep containerized applications portable.
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This page provides a series of usage examples demonstrating how to create ConfigMaps and configure Pods using data stored in ConfigMaps.
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{{% /capture %}}
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{{% capture prerequisites %}}
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{{< include "task-tutorial-prereqs.md" >}} {{< version-check >}}
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{{% /capture %}}
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{{% capture steps %}}
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## Create a ConfigMap
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You can use either `kubectl create configmap` or a ConfigMap generator in `kustomization.yaml` to create a ConfigMap.
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Note that `kubectl` starts to support `kustomization.yaml` since 1.14.
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### Create a ConfigMap Using kubectl create configmap
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Use the `kubectl create configmap` command to create configmaps from [directories](#create-configmaps-from-directories), [files](#create-configmaps-from-files), or [literal values](#create-configmaps-from-literal-values):
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```shell
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kubectl create configmap <map-name> <data-source>
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```
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where \<map-name> is the name you want to assign to the ConfigMap and \<data-source> is the directory, file, or literal value to draw the data from.
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The data source corresponds to a key-value pair in the ConfigMap, where
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* key = the file name or the key you provided on the command line, and
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* value = the file contents or the literal value you provided on the command line.
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You can use [`kubectl describe`](/docs/reference/generated/kubectl/kubectl-commands/#describe) or [`kubectl get`](/docs/reference/generated/kubectl/kubectl-commands/#get) to retrieve information about a ConfigMap.
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#### Create ConfigMaps from directories
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You can use `kubectl create configmap` to create a ConfigMap from multiple files in the same directory.
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For example:
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```shell
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# Create the local directory
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mkdir -p configure-pod-container/configmap/
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# Download the sample files into `configure-pod-container/configmap/` directory
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wget https://kubernetes.io/examples/configmap/game.properties -O configure-pod-container/configmap/game.properties
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wget https://kubernetes.io/examples/configmap/ui.properties -O configure-pod-container/configmap/ui.properties
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# Create the configmap
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kubectl create configmap game-config --from-file=configure-pod-container/configmap/
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```
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combines the contents of the `configure-pod-container/configmap/` directory
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```shell
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game.properties
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ui.properties
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```
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into the following ConfigMap:
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```shell
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kubectl describe configmaps game-config
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```
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where the output is similar to this:
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```text
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Name: game-config
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Namespace: default
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Labels: <none>
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Annotations: <none>
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Data
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====
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game.properties: 158 bytes
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ui.properties: 83 bytes
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```
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The `game.properties` and `ui.properties` files in the `configure-pod-container/configmap/` directory are represented in the `data` section of the ConfigMap.
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```shell
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kubectl get configmaps game-config -o yaml
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```
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The output is similar to this:
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```yaml
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apiVersion: v1
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kind: ConfigMap
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metadata:
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creationTimestamp: 2016-02-18T18:52:05Z
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name: game-config
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namespace: default
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resourceVersion: "516"
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uid: b4952dc3-d670-11e5-8cd0-68f728db1985
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data:
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game.properties: |
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enemies=aliens
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lives=3
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enemies.cheat=true
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enemies.cheat.level=noGoodRotten
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secret.code.passphrase=UUDDLRLRBABAS
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secret.code.allowed=true
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secret.code.lives=30
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ui.properties: |
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color.good=purple
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color.bad=yellow
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allow.textmode=true
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how.nice.to.look=fairlyNice
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```
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#### Create ConfigMaps from files
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You can use `kubectl create configmap` to create a ConfigMap from an individual file, or from multiple files.
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For example,
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```shell
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kubectl create configmap game-config-2 --from-file=configure-pod-container/configmap/game.properties
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```
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would produce the following ConfigMap:
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```shell
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kubectl describe configmaps game-config-2
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```
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where the output is similar to this:
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```text
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Name: game-config-2
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Namespace: default
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Labels: <none>
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Annotations: <none>
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Data
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====
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game.properties: 158 bytes
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```
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You can pass in the `--from-file` argument multiple times to create a ConfigMap from multiple data sources.
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```shell
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kubectl create configmap game-config-2 --from-file=configure-pod-container/configmap/game.properties --from-file=configure-pod-container/configmap/ui.properties
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```
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Describe the above `game-config-2` configmap created
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```shell
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kubectl describe configmaps game-config-2
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```
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The output is similar to this:
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```text
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Name: game-config-2
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Namespace: default
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Labels: <none>
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Annotations: <none>
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Data
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====
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game.properties: 158 bytes
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ui.properties: 83 bytes
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```
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Use the option `--from-env-file` to create a ConfigMap from an env-file, for example:
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```shell
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# Env-files contain a list of environment variables.
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# These syntax rules apply:
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# Each line in an env file has to be in VAR=VAL format.
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# Lines beginning with # (i.e. comments) are ignored.
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# Blank lines are ignored.
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# There is no special handling of quotation marks (i.e. they will be part of the ConfigMap value)).
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# Download the sample files into `configure-pod-container/configmap/` directory
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wget https://kubernetes.io/examples/configmap/game-env-file.properties -O configure-pod-container/configmap/game-env-file.properties
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# The env-file `game-env-file.properties` looks like below
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cat configure-pod-container/configmap/game-env-file.properties
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enemies=aliens
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lives=3
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allowed="true"
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# This comment and the empty line above it are ignored
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```
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```shell
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kubectl create configmap game-config-env-file \
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--from-env-file=configure-pod-container/configmap/game-env-file.properties
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```
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would produce the following ConfigMap:
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```shell
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kubectl get configmap game-config-env-file -o yaml
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```
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where the output is similar to this:
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```yaml
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apiVersion: v1
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kind: ConfigMap
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metadata:
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creationTimestamp: 2017-12-27T18:36:28Z
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name: game-config-env-file
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namespace: default
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resourceVersion: "809965"
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uid: d9d1ca5b-eb34-11e7-887b-42010a8002b8
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data:
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allowed: '"true"'
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enemies: aliens
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lives: "3"
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```
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{{< caution >}}
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When passing `--from-env-file` multiple times to create a ConfigMap from multiple data sources, only the last env-file is used.
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{{< /caution >}}
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The behavior of passing `--from-env-file` multiple times is demonstrated by:
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```shell
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# Download the sample files into `configure-pod-container/configmap/` directory
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wget https://k8s.io/examples/configmap/ui-env-file.properties -O configure-pod-container/configmap/ui-env-file.properties
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# Create the configmap
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kubectl create configmap config-multi-env-files \
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--from-env-file=configure-pod-container/configmap/game-env-file.properties \
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--from-env-file=configure-pod-container/configmap/ui-env-file.properties
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```
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would produce the following ConfigMap:
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```shell
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kubectl get configmap config-multi-env-files -o yaml
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```
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where the output is similar to this:
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```yaml
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apiVersion: v1
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kind: ConfigMap
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metadata:
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creationTimestamp: 2017-12-27T18:38:34Z
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name: config-multi-env-files
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namespace: default
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resourceVersion: "810136"
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uid: 252c4572-eb35-11e7-887b-42010a8002b8
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data:
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color: purple
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how: fairlyNice
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textmode: "true"
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```
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#### Define the key to use when creating a ConfigMap from a file
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You can define a key other than the file name to use in the `data` section of your ConfigMap when using the `--from-file` argument:
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```shell
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kubectl create configmap game-config-3 --from-file=<my-key-name>=<path-to-file>
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```
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where `<my-key-name>` is the key you want to use in the ConfigMap and `<path-to-file>` is the location of the data source file you want the key to represent.
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For example:
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```shell
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kubectl create configmap game-config-3 --from-file=game-special-key=configure-pod-container/configmap/game.properties
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```
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would produce the following ConfigMap:
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```shell
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kubectl get configmaps game-config-3 -o yaml
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```
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where the output is similar to this:
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```yaml
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apiVersion: v1
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kind: ConfigMap
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metadata:
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creationTimestamp: 2016-02-18T18:54:22Z
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name: game-config-3
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namespace: default
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resourceVersion: "530"
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uid: 05f8da22-d671-11e5-8cd0-68f728db1985
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data:
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game-special-key: |
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enemies=aliens
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lives=3
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enemies.cheat=true
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enemies.cheat.level=noGoodRotten
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secret.code.passphrase=UUDDLRLRBABAS
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secret.code.allowed=true
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secret.code.lives=30
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```
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#### Create ConfigMaps from literal values
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You can use `kubectl create configmap` with the `--from-literal` argument to define a literal value from the command line:
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```shell
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kubectl create configmap special-config --from-literal=special.how=very --from-literal=special.type=charm
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```
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You can pass in multiple key-value pairs.
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Each pair provided on the command line is represented as a separate entry in the `data` section of the ConfigMap.
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```shell
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kubectl get configmaps special-config -o yaml
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```
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The output is similar to this:
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```yaml
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apiVersion: v1
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kind: ConfigMap
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metadata:
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creationTimestamp: 2016-02-18T19:14:38Z
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name: special-config
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namespace: default
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resourceVersion: "651"
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uid: dadce046-d673-11e5-8cd0-68f728db1985
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data:
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special.how: very
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special.type: charm
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```
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### Create a ConfigMap from generator
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`kubectl` supports `kustomization.yaml` since 1.14.
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You can also create a ConfigMap from generators and then apply it to create the object on the Apiserver.
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The generators should be specified in a `kustomization.yaml` inside a directory.
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#### Generate ConfigMaps from files
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For example, to generate a ConfigMap from files `configure-pod-container/configmap/game.properties`
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```shell
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# Create a kustomization.yaml file with ConfigMapGenerator
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cat <<EOF >./kustomization.yaml
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configMapGenerator:
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- name: game-config-4
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files:
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- configure-pod-container/configmap/game.properties
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EOF
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```
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Apply the kustomization directory to create the ConfigMap object.
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```shell
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kubectl apply -k .
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configmap/game-config-4-m9dm2f92bt created
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```
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You can check that the ConfigMap was created like this:
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```text
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kubectl get configmap
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NAME DATA AGE
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game-config-4-m9dm2f92bt 1 37s
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kubectl describe configmaps/game-config-4-m9dm2f92bt
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Name: game-config-4-m9dm2f92bt
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Namespace: default
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Labels: <none>
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Annotations: kubectl.kubernetes.io/last-applied-configuration:
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{"apiVersion":"v1","data":{"game.properties":"enemies=aliens\nlives=3\nenemies.cheat=true\nenemies.cheat.level=noGoodRotten\nsecret.code.p...
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Data
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====
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game.properties:
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----
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enemies=aliens
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lives=3
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enemies.cheat=true
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enemies.cheat.level=noGoodRotten
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secret.code.passphrase=UUDDLRLRBABAS
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secret.code.allowed=true
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secret.code.lives=30
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Events: <none>
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```
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Note that the generated ConfigMap name has a suffix appended by hashing the contents.
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This ensures that a new ConfigMap is generated each time the content is modified.
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#### Define the key to use when generating a ConfigMap from a file
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You can define a key other than the file name to use in the ConfigMap generator.
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For example, to generate a ConfigMap from files `configure-pod-container/configmap/game.properties`
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with the key `game-special-key`
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```shell
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# Create a kustomization.yaml file with ConfigMapGenerator
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cat <<EOF >./kustomization.yaml
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configMapGenerator:
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- name: game-config-5
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files:
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- game-special-key=configure-pod-container/configmap/game.properties
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EOF
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```
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Apply the kustomization directory to create the ConfigMap object.
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```text
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kubectl apply -k .
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configmap/game-config-5-m67dt67794 created
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```
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#### Generate ConfigMaps from Literals
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To generate a ConfigMap from literals `special.type=charm` and `special.how=very`, you can specify the ConfigMap generator in `kustomization.yaml` as
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```shell
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# Create a kustomization.yaml file with ConfigMapGenerator
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cat <<EOF >./kustomization.yaml
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configMapGenerator:
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- name: special-config-2
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literals:
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- special.how=very
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- special.type=charm
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EOF
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```
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Apply the kustomization directory to create the ConfigMap object.
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```text
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kubectl apply -k .
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configmap/special-config-2-c92b5mmcf2 created
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```
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## Define container environment variables using ConfigMap data
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### Define a container environment variable with data from a single ConfigMap
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1. Define an environment variable as a key-value pair in a ConfigMap:
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```shell
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kubectl create configmap special-config --from-literal=special.how=very
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```
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1. Assign the `special.how` value defined in the ConfigMap to the `SPECIAL_LEVEL_KEY` environment variable in the Pod specification.
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{{< codenew file="pods/pod-single-configmap-env-variable.yaml" >}}
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Create the Pod:
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```shell
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kubectl create -f https://kubernetes.io/examples/pods/pod-single-configmap-env-variable.yaml
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```
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Now, the Pod's output includes environment variable `SPECIAL_LEVEL_KEY=very`.
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### Define container environment variables with data from multiple ConfigMaps
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* As with the previous example, create the ConfigMaps first.
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{{< codenew file="configmap/configmaps.yaml" >}}
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Create the ConfigMap:
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```shell
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kubectl create -f https://kubernetes.io/examples/configmap/configmaps.yaml
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```
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* Define the environment variables in the Pod specification.
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{{< codenew file="pods/pod-multiple-configmap-env-variable.yaml" >}}
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Create the Pod:
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```shell
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kubectl create -f https://kubernetes.io/examples/pods/pod-multiple-configmap-env-variable.yaml
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```
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Now, the Pod's output includes environment variables `SPECIAL_LEVEL_KEY=very` and `LOG_LEVEL=INFO`.
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## Configure all key-value pairs in a ConfigMap as container environment variables
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{{< note >}}
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This functionality is available in Kubernetes v1.6 and later.
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{{< /note >}}
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* Create a ConfigMap containing multiple key-value pairs.
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{{< codenew file="configmap/configmap-multikeys.yaml" >}}
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Create the ConfigMap:
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```shell
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kubectl create -f https://kubernetes.io/examples/configmap/configmap-multikeys.yaml
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```
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* Use `envFrom` to define all of the ConfigMap's data as container environment variables.
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The key from the ConfigMap becomes the environment variable name in the Pod.
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{{< codenew file="pods/pod-configmap-envFrom.yaml" >}}
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Create the Pod:
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```shell
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kubectl create -f https://kubernetes.io/examples/pods/pod-configmap-envFrom.yaml
|
||||
```
|
||||
|
||||
Now, the Pod's output includes environment variables `SPECIAL_LEVEL=very` and `SPECIAL_TYPE=charm`.
|
||||
|
||||
## Use ConfigMap-defined environment variables in Pod commands
|
||||
|
||||
You can use ConfigMap-defined environment variables in the `command` section of the Pod specification using the `$(VAR_NAME)` Kubernetes substitution syntax.
|
||||
|
||||
For example, the following Pod specification
|
||||
|
||||
{{< codenew file="pods/pod-configmap-env-var-valueFrom.yaml" >}}
|
||||
|
||||
created by running
|
||||
|
||||
```shell
|
||||
kubectl create -f https://kubernetes.io/examples/pods/pod-configmap-env-var-valueFrom.yaml
|
||||
```
|
||||
|
||||
produces the following output in the `test-container` container:
|
||||
|
||||
```shell
|
||||
very charm
|
||||
```
|
||||
|
||||
## Add ConfigMap data to a Volume
|
||||
|
||||
As explained in [Create ConfigMaps from files](#create-configmaps-from-files), when you create a ConfigMap using ``--from-file``, the filename becomes a key stored in the `data` section of the ConfigMap. The file contents become the key's value.
|
||||
|
||||
The examples in this section refer to a ConfigMap named special-config, shown below.
|
||||
|
||||
{{< codenew file="configmap/configmap-multikeys.yaml" >}}
|
||||
|
||||
Create the ConfigMap:
|
||||
|
||||
```shell
|
||||
kubectl create -f https://kubernetes.io/examples/configmap/configmap-multikeys.yaml
|
||||
```
|
||||
|
||||
### Populate a Volume with data stored in a ConfigMap
|
||||
|
||||
Add the ConfigMap name under the `volumes` section of the Pod specification.
|
||||
This adds the ConfigMap data to the directory specified as `volumeMounts.mountPath` (in this case, `/etc/config`).
|
||||
The `command` section lists directory files with names that match the keys in ConfigMap.
|
||||
|
||||
{{< codenew file="pods/pod-configmap-volume.yaml" >}}
|
||||
|
||||
Create the Pod:
|
||||
|
||||
```shell
|
||||
kubectl create -f https://kubernetes.io/examples/pods/pod-configmap-volume.yaml
|
||||
```
|
||||
|
||||
When the pod runs, the command `ls /etc/config/` produces the output below:
|
||||
|
||||
```shell
|
||||
SPECIAL_LEVEL
|
||||
SPECIAL_TYPE
|
||||
```
|
||||
|
||||
{{< caution >}}
|
||||
If there are some files in the `/etc/config/` directory, they will be deleted.
|
||||
{{< /caution >}}
|
||||
|
||||
### Add ConfigMap data to a specific path in the Volume
|
||||
|
||||
Use the `path` field to specify the desired file path for specific ConfigMap items.
|
||||
In this case, the `SPECIAL_LEVEL` item will be mounted in the `config-volume` volume at `/etc/config/keys`.
|
||||
|
||||
{{< codenew file="pods/pod-configmap-volume-specific-key.yaml" >}}
|
||||
|
||||
Create the Pod:
|
||||
|
||||
```shell
|
||||
kubectl create -f https://kubernetes.io/examples/pods/pod-configmap-volume-specific-key.yaml
|
||||
```
|
||||
|
||||
When the pod runs, the command `cat /etc/config/keys` produces the output below:
|
||||
|
||||
```shell
|
||||
very
|
||||
```
|
||||
|
||||
{{< caution >}}
|
||||
Like before, all previous files in the `/etc/config/` directory will be deleted.
|
||||
{{< /caution >}}
|
||||
|
||||
### Project keys to specific paths and file permissions
|
||||
|
||||
You can project keys to specific paths and specific permissions on a per-file
|
||||
basis. The [Secrets](/docs/concepts/configuration/secret/#using-secrets-as-files-from-a-pod) user guide explains the syntax.
|
||||
|
||||
### Mounted ConfigMaps are updated automatically
|
||||
|
||||
When a ConfigMap already being consumed in a volume is updated, projected keys are eventually updated as well. Kubelet is checking whether the mounted ConfigMap is fresh on every periodic sync. However, it is using its local ttl-based cache for getting the current value of the ConfigMap. As a result, the total delay from the moment when the ConfigMap is updated to the moment when new keys are projected to the pod can be as long as kubelet sync period (1 minute by default) + ttl of ConfigMaps cache (1 minute by default) in kubelet. You can trigger an immediate refresh by updating one of the pod's annotations.
|
||||
|
||||
{{< note >}}
|
||||
A container using a ConfigMap as a [subPath](/docs/concepts/storage/volumes/#using-subpath) volume will not receive ConfigMap updates.
|
||||
{{< /note >}}
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture discussion %}}
|
||||
|
||||
## Understanding ConfigMaps and Pods
|
||||
|
||||
The ConfigMap API resource stores configuration data as key-value pairs. The data can be consumed in pods or provide the configurations for system components such as controllers. ConfigMap is similar to [Secrets](/docs/concepts/configuration/secret/), but provides a means of working with strings that don't contain sensitive information. Users and system components alike can store configuration data in ConfigMap.
|
||||
|
||||
{{< note >}}
|
||||
ConfigMaps should reference properties files, not replace them. Think of the ConfigMap as representing something similar to the Linux `/etc` directory and its contents. For example, if you create a [Kubernetes Volume](/docs/concepts/storage/volumes/) from a ConfigMap, each data item in the ConfigMap is represented by an individual file in the volume.
|
||||
{{< /note >}}
|
||||
|
||||
The ConfigMap's `data` field contains the configuration data. As shown in the example below, this can be simple -- like individual properties defined using `--from-literal` -- or complex -- like configuration files or JSON blobs defined using `--from-file`.
|
||||
|
||||
```yaml
|
||||
apiVersion: v1
|
||||
kind: ConfigMap
|
||||
metadata:
|
||||
creationTimestamp: 2016-02-18T19:14:38Z
|
||||
name: example-config
|
||||
namespace: default
|
||||
data:
|
||||
# example of a simple property defined using --from-literal
|
||||
example.property.1: hello
|
||||
example.property.2: world
|
||||
# example of a complex property defined using --from-file
|
||||
example.property.file: |-
|
||||
property.1=value-1
|
||||
property.2=value-2
|
||||
property.3=value-3
|
||||
```
|
||||
|
||||
### Restrictions
|
||||
|
||||
* You must create a ConfigMap before referencing it in a Pod specification (unless you mark the ConfigMap as "optional").
|
||||
If you reference a ConfigMap that doesn't exist, the Pod won't start.
|
||||
Likewise, references to keys that don't exist in the ConfigMap will prevent the pod from starting.
|
||||
|
||||
* If you use `envFrom` to define environment variables from ConfigMaps, keys that are considered invalid will be skipped.
|
||||
The pod will be allowed to start, but the invalid names will be recorded in the event log (`InvalidVariableNames`).
|
||||
The log message lists each skipped key.
|
||||
For example:
|
||||
|
||||
```shell
|
||||
kubectl get events
|
||||
```
|
||||
|
||||
The output is similar to this:
|
||||
|
||||
```text
|
||||
LASTSEEN FIRSTSEEN COUNT NAME KIND SUBOBJECT TYPE REASON SOURCE MESSAGE
|
||||
0s 0s 1 dapi-test-pod Pod Warning InvalidEnvironmentVariableNames {kubelet, 127.0.0.1} Keys [1badkey, 2alsobad] from the EnvFrom configMap default/myconfig were skipped since they are considered invalid environment variable names.
|
||||
```
|
||||
|
||||
* ConfigMaps reside in a specific {{< glossary_tooltip term_id="namespace" >}}.
|
||||
A ConfigMap can only be referenced by pods residing in the same namespace.
|
||||
|
||||
* You can't use ConfigMaps for {{< glossary_tooltip text="static pods" term_id="static-pod" >}}, because the Kubelet does not support this.
|
||||
|
||||
{{% /capture %}}
|
||||
|
||||
{{% capture whatsnext %}}
|
||||
|
||||
* Follow a real world example of [Configuring Redis using a ConfigMap](/docs/tutorials/configuration/configure-redis-using-configmap/).
|
||||
|
||||
{{% /capture %}}
|
||||
Loading…
Reference in New Issue