Mounting ConfigMaps and Secrets as files

Mounting application configuration maps and secrets as files

In Kubernetes, you can mount ConfigMap or Secret data as files into a container, allowing your workloads to read configuration values at runtime without hardcoding them into images or code.

Prerequisites

Before you can mount a ConfigMap or Secret as a file in a container, complete the following setup:

• Create a DuploCloud Service. The Service defines the container into which the ConfigMap or Secret will be mounted. You can create a Service by navigating to Kubernetes → Services in the DuploCloud Portal.

• Create the ConfigMap or Secret.

  • To create a ConfigMap, see Creating a Kubernetes ConfigMap.

  • To create a Secret, see Creating a Kubernetes Secret.

Each ConfigMap or Secret should include the file data you want to mount, using key/value pairs where the key is the filename and the value is the file’s contents.

Mounting a Kubernetes ConfigMap as a Volume

1. In the DuploCloud Portal, navigate to Kubernetes -> Services.

2. Select the Service you want to modify from the Name column.

3. Click the Actions menu and select Edit.

4. Click Next. The Advanced Options page displays.

5. In the Volumes field on the Advanced Options page, enter the appropriate YAML configuration to define the volume mount. See examples below.

Example: Mounting a ConfigMap as a Volume

To mount a ConfigMap named my-config-map to a directory named /app/my-config, use the following configuration:

- Name: my-config
  Path: /app/my-config
  Spec:
    ConfigMap:
      Name: my-config-map

The nginx Service Advanced Options page in the DuploCloud Portal

Example: Mounting an Individual File from a ConfigMap

To mount an individual file (e.g., my-file-name) from the ConfigMap to a specific location (e.g., /app/my-config/config-file), use the following configuration:

  Path: /app/my-config
  Spec:
    ConfigMap:
      Name: my-config-map
      Items:
      - Key: my-file-name
        Path: config-file

1. Select Update to save the configuration. The ConfigMap will now be mounted into the container at runtime.

Mounting a Kubernetes Secret as a Volume

1. In the DuploCloud Portal, navigate to Kubernetes -> Services.

2. Select the Service you want to modify from the Name column.

3. Click the Actions menu and select Edit.

4. Click Next. The Advanced Options page displays.

   

   The nginx Service Advanced Options page in the DuploCloud Portal
5. In the Volumes field on the Advanced Options page, enter the appropriate YAML configuration to define the volume mount. See examples below.

Example: Mounting a Secret as a Volume

To mount a Secret named my-secret-files to a directory named /app/my-config, use the following configuration:

- Name: my-config
  Path: /app/my-config
  Spec:
    Secret:
      SecretName: my-secret-files

Example: Mounting an Individual Secret Item

If you want to select individual Secret items (e.g., secret-file) and specify the subpath for mounting (e.g., /app/my-config/config-file) use the following configuration:

- Name: my-config
  Path: /app/my-config
  Spec:
    Secret:
      SecretName: my-secret-files
      Items:
      - Key: secret-file
        Path: config-file

1. Select Update to save the configuration. The Secret will now be mounted into the container at runtime.