# Application

The **Grey Matter application** is configured with the following environment variables set on the host machine. The term host machine can apply to an AWS EC2 server, Docker container, Kubernetes Pod, etc.

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**Note:** to apply new configs, you must restart the application process on the host machine.
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## Configuration Variables

| Name                           | Type    | Default                                                 | Description                                                                                                                                                                                                      |   |
| ------------------------------ | ------- | ------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | - |
| `BASE_URL`                     | String  | "/"                                                     | Base URL, relative to the Grey Matter installation's hostname                                                                                                                                                    |   |
| `CONFIG_SERVER`                | String  | `http://localhost:5555/v1.0/`                           | Control API endpoint (for retrieving mesh configuration of services)                                                                                                                                             |   |
| `DISABLE_PROMETHEUS_ROUTES_UI` | Boolean | false                                                   | When set to `true`, disables parts of the UI that use route metrics from Prometheus - service summary view route-level metrics, service routes view entirely, and route SLOs in the service configuration panel. |   |
| `ENABLE_INLINE_DOCS`           | Boolean | false                                                   | Enables inline API documentation in service and instance views.                                                                                                                                                  |   |
| `EXPOSE_SOURCE_MAPS`           | Boolean | false                                                   | Expose JavaScript source maps to web browsers in production (recommended for debugging only)                                                                                                                     |   |
| `FABRIC_SERVER`                | String  | `http://localhost:1337/services/catalog/1.0/`           | Catalog endpoint (for retrieving metadata of mesh services)                                                                                                                                                      |   |
| `HIDE_EXTERNAL_LINKS`          | Boolean | false                                                   | Hide Grey Matter social links in the app footer                                                                                                                                                                  |   |
| `OBJECTIVES_SERVER`            | String  | `http://localhost:1337/services/slo/1.0/`               | Service Level Objectives endpoint (for retrieving and setting performance objectives)                                                                                                                            |   |
| `PROMETHEUS_SERVER`            | String  | `http://localhost:1337/services/prometheus/2.3/api/v1/` | Prometheus endpoint (for retrieving historical service metrics)                                                                                                                                                  |   |
| `REQUEST_TIMEOUT`              | Integer | 5000                                                    | Number of milliseconds a request to backend services can take before returning a client error                                                                                                                    |   |
| `SERVER_SSL_CA`                | String  | ""                                                      | Path to client trust file (`SERVER_SSL_ENABLED=true` is required)                                                                                                                                                |   |
| `SERVER_SSL_CERT`              | String  | ""                                                      | Path to client certificate (`SERVER_SSL_ENABLED=true` is required)                                                                                                                                               |   |
| `SERVER_SSL_ENABLED`           | Boolean | false                                                   | Informs service to receive client connections over SSL only                                                                                                                                                      |   |
| `SERVER_SSL_KEY`               | String  | ""                                                      | Path to client private key (`SERVER_SSL_ENABLED=true` is required)                                                                                                                                               |   |
| `SERVICES_PER_PAGE`            | Integer | 20                                                      | How many services should be displayed per page in the Fabric View               views.                                                                                                                           |   |
| `USE_PROMETHEUS`               | Boolean | true                                                    | Use Prometheus to query service-level metrics                                                                                                                                                                    |   |

## Questions

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**Need help setting up the Grey Matter application?** Create an account at [Grey Matter Support](https://support.greymatter.io/support/home) to reach our team.
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