---
alias: operation-guide-environmentvariables
tags:
- containerized environments
- configuration
description: "Environment variables configure container settings within the Critical Manufacturing MES deployment"
---

# System Configuration through Environment Variables

When using Docker compose to run any container that is an integral part of the Critical Manufacturing MES, a specific number of environment variables are set in the container that is started through Docker Compose and the use of a `docker-compose.yml` file which will then internally use them. Below you can find a list of those variables as well as a small explanation for each one:

## Secrets

As per the definition retrieved from the official Docker documentation on <https://docs.docker.com/engine/swarm/secrets/>:

    A secret is a blob of data, such as a password, SSH private key, SSL certificate, or another piece of data that should not be transmitted over a network or stored unencrypted in a Dockerfile or in your application's source code. 

The secrets are defined in the YAML file for the Docker Compose and contain paths to another file that is hosted in an internal location, inaccessible from anyone without administrator access to the server. A quick example follows:

```yaml
DATABASE_ONLINE_MSSQL_PASSWORD_FILE: /some/local/path/DATABASE_ONLINE_MSSQL_PASSWORD
```

This means that the value that will be used in the Docker container for `DATABASE_ONLINE_MSSQL_PASSWORD_FILE` will be retrieved from the contents of the `/some/local/path/DATABASE_ONLINE_MSSQL_PASSWORD` file

{% include-markdown 'includes/docsync/dockerenvironmentvariables.md' %}