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Using Harness Config Variables in Manifests

This content is for Harness FirstGen. Switch to NextGen.

You can create a variable in the Harness Kubernetes Service Config Variables section and then use it in your Manifests files, such as in the ConfigMap definition.

Before You Begin​

In Harness Kubernetes version 1 implementation, Harness would create the ConfigMap automatically using the ${CONFIG_MAP_NAME} expression and all unencrypted Service Config Variables and Config Files. In the current Harness Kubernetes implementation, you define your ConfigMap manually using the values.yaml and Config Variables and Config Files.

Review: Config Variable Reference Scope​

You cannot reference a Service's Config Variable in the Pre-Deployment Phase of a Workflow. Canary and Multi-Service Workflows are the only Workflow types with the Pre-Deployment Phase.

The Pre-Deployment Phase does not use a Service and so it has no access to Service Config Variables (or Config Files).

You can reference a Service's Config Variable in the Deployment Phase of the Workflow.

Step 1: Create the Service Variable in Config Variables​

For this explanation, we'll create a variable that indicates the database to use for a ConfigMap.

  1. In Config Variables, click Add Variable.

  2. In Config Variable, add a variable named database with the value mongodb.

  3. Click Submit. The variable is added to the Config Variables section.

Step 2: Reference the Service Variable in values.yaml​

  1. In values.yaml, create a new variable named databaseType that references the Service variable database:

Step 3: Reference the Variable in the Manifest​

  1. In the manifest file containing you object (in this example, ConfigMap), reference the values.yaml variable in the ConfigMap data section.

When the Service is deployed, the Service variable will be used to provide the value mongodb to the data label in ConfigMap.

Notes​

  • You can also overwrite the Service variable in an Environment Service Configuration Override. When a Workflow using that Service and Environment deploys, the Service variable for the ConfigMap data value will be overwritten. See Override Harness Kubernetes Service Settings.

Next Steps​