Mount ConfigMaps

Mount Kubernetes ConfigMaps into workspace containers to provide non-sensitive configuration data.

Prerequisites

You have an active kubectl session with your namespace. See Overview of kubectl.

By default, applying a ConfigMap with the controller.devfile.io/mount-to-devworkspace: 'true' label restarts all running workspaces in the namespace. To mount the ConfigMap only at workspace start and prevent automatic restarts, add the controller.devfile.io/mount-on-start: 'true' annotation.

Procedure

Create a ConfigMap with the required labels and annotations:
```
kind: ConfigMap
apiVersion: v1
metadata:
  name: my-config
  labels:
    controller.devfile.io/mount-to-devworkspace: 'true'
    controller.devfile.io/watch-configmap: 'true'
  annotations:
    controller.devfile.io/mount-as: file
    controller.devfile.io/mount-path: /etc/my-config
data:
  settings.json: |
    {
      "editor.fontSize": 14,
      "editor.tabSize": 2
    }
```
where:

controller.devfile.io/mount-to-devworkspace

Required label to mount the ConfigMap to all workspaces.

controller.devfile.io/watch-configmap

Watch the ConfigMap for changes and update mounted files.

controller.devfile.io/mount-as

Mount type: file, subpath, or env.

controller.devfile.io/mount-path

Path where the ConfigMap data is mounted.

Apply the ConfigMap to your namespace:

$ kubectl apply -f my-config.yaml -n <your_namespace>

Optional: Add annotations to the ConfigMap to customize the mounting behavior.

Table 1. ConfigMap mounting annotations
Annotation	Description
`controller.devfile.io/mount-path: <path>`	Overrides the default mount path. The default mount path is `/etc/config/<ConfigMap_name>`.
`controller.devfile.io/mount-as: file`	Each key in the ConfigMap data becomes a file in the mount path directory.
`controller.devfile.io/mount-as: subpath`	Similar to `file`, but uses subPath volumes for better compatibility.
`controller.devfile.io/mount-as: env`	Each key-value pair becomes an environment variable in all workspace containers.
`controller.devfile.io/mount-on-start: 'true'`	When set to `true`, the ConfigMap is mounted only when a workspace starts, not while it is already running. This prevents workspace restarts when the ConfigMap is created.
`controller.devfile.io/mount-to-devworkspace-include:`	Specifies a comma-separated list of `DevWorkspace` name patterns. When set, the ConfigMap is mounted only to workspaces whose names match at least one pattern.
`controller.devfile.io/mount-to-devworkspace-exclude:`	Specifies a comma-separated list of `DevWorkspace` name patterns. When set, the ConfigMap is mounted to all workspaces except those whose names match a pattern.

When both controller.devfile.io/mount-to-devworkspace-include and controller.devfile.io/mount-to-devworkspace-exclude annotations are set, the ConfigMap is mounted only to workspaces that match the include pattern and do not match the exclude pattern.

For example, to mount ConfigMap data as environment variables:

kind: ConfigMap
apiVersion: v1
metadata:
  name: my-env-config
  labels:
    controller.devfile.io/mount-to-devworkspace: 'true'
    controller.devfile.io/watch-configmap: 'true'
  annotations:
    controller.devfile.io/mount-as: env
data:
  LOG_LEVEL: debug
  MAX_CONNECTIONS: "100"

Start or restart your workspace to apply the mounted ConfigMap.

Verification

For file or subpath mounts, verify the ConfigMap data is available at the mount path:
```
$ cat /etc/my-config/settings.json
```
For env mounts, verify the environment variables are set:
```
$ echo $LOG_LEVEL
```

Additional resources