Update ConfigMap docs (#6648)
Currently we have two diferent doc pages to configure pod using ConfigMaps. There are redundency between these two docs and also it creates some confusion using the doc. Merging these two docs into single page and removing redundency etc.
This commit is contained in:
Sahdev Zala
Steve Perry
parent
20a0cb88d6
commit
746446b441
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@ -1,258 +0,0 @@
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---
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approvers:
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- eparis
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- pmorie
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title: Configure Containers Using a ConfigMap
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---
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{% capture overview %}
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This page shows you how to configure an application using a ConfigMap. ConfigMaps allow you to decouple configuration artifacts from image content to keep containerized applications portable.
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{% endcapture %}
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{% capture prerequisites %}
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* {% include task-tutorial-prereqs.md %}
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{% endcapture %}
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{% capture steps %}
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## Use kubectl to create a 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/user-guide/kubectl/{{page.version}}/#describe) or
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[`kubectl get`](/docs/user-guide/kubectl/{{page.version}}/#get) to retrieve information
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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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kubectl create configmap game-config --from-file=docs/user-guide/configmap/kubectl
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```
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combines the contents of the `docs/user-guide/configmap/kubectl/` directory
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```shell
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ls docs/user-guide/configmap/kubectl/
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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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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 `docs/user-guide/configmap/kubectl/` 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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```yaml
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apiVersion: v1
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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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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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selfLink: /api/v1/namespaces/default/configmaps/game-config-2
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uid: b4952dc3-d670-11e5-8cd0-68f728db1985
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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=docs/user-guide/configmap/kubectl/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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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=docs/user-guide/configmap/kubectl/game.properties --from-file=docs/user-guide/configmap/kubectl/ui.properties
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```
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```shell
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kubectl describe configmaps game-config-2
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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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#### 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=docs/user-guide/configmap/kubectl/game.properties
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kubectl get configmaps game-config-3 -o yaml
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```
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```yaml
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apiVersion: v1
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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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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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selfLink: /api/v1/namespaces/default/configmaps/game-config-3
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uid: 05f8da22-d671-11e5-8cd0-68f728db1985
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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. 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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```yaml
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apiVersion: v1
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data:
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special.how: very
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special.type: charm
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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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selfLink: /api/v1/namespaces/default/configmaps/special-config
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uid: dadce046-d673-11e5-8cd0-68f728db1985
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```
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{% endcapture %}
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{% capture discussion %}
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## Understanding ConfigMaps
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ConfigMaps allow you to decouple configuration artifacts from image content to keep containerized applications portable.
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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.
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**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.
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{: .note}
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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`.
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```yaml
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kind: ConfigMap
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apiVersion: v1
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metadata:
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creationTimestamp: 2016-02-18T19:14:38Z
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name: example-config
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namespace: default
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data:
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# example of a simple property defined using --from-literal
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example.property.1: hello
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example.property.2: world
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# example of a complex property defined using --from-file
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example.property.file: |-
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property.1=value-1
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property.2=value-2
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property.3=value-3
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```
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{% endcapture %}
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{% capture whatsnext %}
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* See [Using ConfigMap Data in Pods](/docs/tasks/configure-pod-container/configure-pod-configmap).
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* Follow a real world example of [Configuring Redis using a ConfigMap](/docs/tutorials/configuration/configure-redis-using-configmap/).
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{% endcapture %}
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{% include templates/task.md %}
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@ -1,19 +1,217 @@
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---
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title: Use ConfigMap Data in Pods
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title: Configure a Pod to Use a ConfigMap
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---
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{% capture overview %}
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This page provides a series of usage examples demonstrating how to configure Pods using data stored in ConfigMaps.
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ConfigMaps allow you to decouple configuration artifacts from image content to keep containerized applications portable. 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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{% endcapture %}
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{% capture prerequisites %}
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* {% include task-tutorial-prereqs.md %}
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* [Create a ConfigMap](/docs/tasks/configure-pod-container/configmap/)
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{% include task-tutorial-prereqs.md %}
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{% endcapture %}
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{% capture steps %}
|
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## Create a 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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|
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```shell
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kubectl create configmap <map-name> <data-source>
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```
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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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|
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The data source corresponds to a key-value pair in the ConfigMap, where
|
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|
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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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|
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You can use [`kubectl describe`](/docs/user-guide/kubectl/{{page.version}}/#describe) or
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[`kubectl get`](/docs/user-guide/kubectl/{{page.version}}/#get) to retrieve information
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about a ConfigMap.
|
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|
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### Create ConfigMaps from directories
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|
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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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|
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For example:
|
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|
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```shell
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kubectl create configmap game-config --from-file=docs/user-guide/configmap/kubectl
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```
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combines the contents of the `docs/user-guide/configmap/kubectl/` directory
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```shell
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ls docs/user-guide/configmap/kubectl/
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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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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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|
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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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|
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The `game.properties` and `ui.properties` files in the `docs/user-guide/configmap/kubectl/` directory are represented in the `data` section of the ConfigMap.
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|
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```shell
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kubectl get configmaps game-config -o yaml
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```
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```yaml
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apiVersion: v1
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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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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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selfLink: /api/v1/namespaces/default/configmaps/game-config-2
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uid: b4952dc3-d670-11e5-8cd0-68f728db1985
|
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```
|
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|
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### Create ConfigMaps from files
|
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|
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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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|
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```shell
|
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kubectl create configmap game-config-2 --from-file=docs/user-guide/configmap/kubectl/game.properties
|
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```
|
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|
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would produce the following ConfigMap:
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|
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```shell
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kubectl describe configmaps game-config-2
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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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|
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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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|
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```shell
|
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kubectl create configmap game-config-2 --from-file=docs/user-guide/configmap/kubectl/game.properties --from-file=docs/user-guide/configmap/kubectl/ui.properties
|
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```
|
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|
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```shell
|
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kubectl describe configmaps game-config-2
|
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Name: game-config-2
|
||||
Namespace: default
|
||||
Labels: <none>
|
||||
Annotations: <none>
|
||||
|
||||
Data
|
||||
====
|
||||
game.properties: 158 bytes
|
||||
ui.properties: 83 bytes
|
||||
```
|
||||
|
||||
#### Define the key to use when creating a ConfigMap from a file
|
||||
|
||||
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:
|
||||
|
||||
```shell
|
||||
kubectl create configmap game-config-3 --from-file=<my-key-name>=<path-to-file>
|
||||
```
|
||||
|
||||
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.
|
||||
|
||||
For example:
|
||||
|
||||
```shell
|
||||
kubectl create configmap game-config-3 --from-file=game-special-key=docs/user-guide/configmap/kubectl/game.properties
|
||||
|
||||
kubectl get configmaps game-config-3 -o yaml
|
||||
```
|
||||
|
||||
```yaml
|
||||
apiVersion: v1
|
||||
data:
|
||||
game-special-key: |
|
||||
enemies=aliens
|
||||
lives=3
|
||||
enemies.cheat=true
|
||||
enemies.cheat.level=noGoodRotten
|
||||
secret.code.passphrase=UUDDLRLRBABAS
|
||||
secret.code.allowed=true
|
||||
secret.code.lives=30
|
||||
kind: ConfigMap
|
||||
metadata:
|
||||
creationTimestamp: 2016-02-18T18:54:22Z
|
||||
name: game-config-3
|
||||
namespace: default
|
||||
resourceVersion: "530"
|
||||
selfLink: /api/v1/namespaces/default/configmaps/game-config-3
|
||||
uid: 05f8da22-d671-11e5-8cd0-68f728db1985
|
||||
```
|
||||
|
||||
### Create ConfigMaps from literal values
|
||||
|
||||
You can use `kubectl create configmap` with the `--from-literal` argument to define a literal value from the command line:
|
||||
|
||||
```shell
|
||||
kubectl create configmap special-config --from-literal=special.how=very --from-literal=special.type=charm
|
||||
```
|
||||
|
||||
You can pass in multiple key-value pairs. Each pair provided on the command line is represented as a separate entry in the `data` section of the ConfigMap.
|
||||
|
||||
```shell
|
||||
kubectl get configmaps special-config -o yaml
|
||||
```
|
||||
|
||||
```yaml
|
||||
apiVersion: v1
|
||||
data:
|
||||
special.how: very
|
||||
special.type: charm
|
||||
kind: ConfigMap
|
||||
metadata:
|
||||
creationTimestamp: 2016-02-18T19:14:38Z
|
||||
name: special-config
|
||||
namespace: default
|
||||
resourceVersion: "651"
|
||||
selfLink: /api/v1/namespaces/default/configmaps/special-config
|
||||
uid: dadce046-d673-11e5-8cd0-68f728db1985
|
||||
```
|
||||
|
||||
|
||||
## Define Pod environment variables using ConfigMap data
|
||||
|
||||
### Define a Pod environment variable with data from a single ConfigMap
|
||||
|
|
@ -284,6 +482,31 @@ When a ConfigMap already being consumed in a volume is updated, projected keys a
|
|||
|
||||
## 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
|
||||
kind: ConfigMap
|
||||
apiVersion: v1
|
||||
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
|
||||
|
||||
1. 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.
|
||||
|
|
@ -299,8 +522,7 @@ When a ConfigMap already being consumed in a volume is updated, projected keys a
|
|||
1. ConfigMaps reside in a specific [namespace](/docs/concepts/overview/working-with-objects/namespaces/). A ConfigMap can only be referenced by pods residing in the same namespace.
|
||||
|
||||
1. Kubelet doesn't support the use of ConfigMaps for pods not found on the API server.
|
||||
This includes every pod created using kubectl or indirectly via a replication controller.
|
||||
It does not include pods created via the Kubelet's `--manifest-url` flag, `--config` flag, or the Kubelet REST API.
|
||||
This includes pods created via the Kubelet's --manifest-url flag, --config flag, or the Kubelet REST API.
|
||||
|
||||
**Note:** These are not commonly-used ways to create pods.
|
||||
{: .note}
|
||||
|
|
@ -308,7 +530,6 @@ When a ConfigMap already being consumed in a volume is updated, projected keys a
|
|||
{% endcapture %}
|
||||
|
||||
{% capture whatsnext %}
|
||||
* Learn more about [ConfigMaps](/docs/tasks/configure-pod-container/configmap/).
|
||||
* Follow a real world example of [Configuring Redis using a ConfigMap](/docs/tutorials/configuration/configure-redis-using-configmap/).
|
||||
|
||||
{% endcapture %}
|
||||
|
|
|
|||
Loading…
Reference in New Issue