[docs-beta] migrate - agent-config.md (dagster-io#26480)

## Summary & Motivation

Note that I renamed the file to `.mdx` since we are using components.
I'm not sure what the etiquette is here, so please let me know if that's
not correct.

You may find this diff helpful.

```
$ diff \
    docs/dagster-plus/deployment/management/environment-variables/agent-config.mdx \
    ../content/dagster-plus/managing-deployments/setting-environment-variables-agents.mdx
```

<img width="2157" alt="image"
src="https://github.com/user-attachments/assets/6ae94d97-abbd-4d2e-8a1e-ea340a458e61"
/>

## How I Tested These Changes

## Changelog

> Insert changelog entry or delete this section.

---------

Co-authored-by: Nikki Everett <[email protected]>

docs/docs-beta/docs/dagster-plus/deployment/management/environment-variables/agent-config.mdx

@@ -0,0 +1,262 @@
+---
+title: "Set environment variables using agent config"
+sidebar_position: 300
+sidebar_label: "Set with agent config"
+---
+
+:::note
+This guide is applicable to Dagster+.
+:::
+
+In this guide, we'll walk you through setting environment variables for a Dagster+ [Hybrid deployment](/dagster-plus/deployment/deployment-types/hybrid) using the Hybrid agent's configuration.
+
+There are two ways to set environment variables:
+
+- **On a per-code location basis**, which involves modifying the `dagster_cloud.yaml` file. **Note**: This approach is functionally the same as [setting environment variables using the Dagster+ UI](/dagster-plus/deployment/management/environment-variables/dagster-ui). Values will pass through Dagster+.
+- **For a full deployment and all the code locations it contains**. This approach makes variables available for all code locations in a full Dagster+ deployment. As values are pulled from the user cluster, values will bypass Dagster+ entirely.
+
+## Prerequisites
+
+To complete the steps in this guide, you'll need:
+
+- A Dagster+ account using [Hybrid deployment](/dagster-plus/deployment/deployment-types/hybrid/)
+- An existing [Hybrid agent](/dagster-plus/deployment/deployment-types/hybrid/#dagster-hybrid-agents)
+- **Editor**, **Admin**, or **Organization Admin** permissions in Dagster+
+
+## Setting environment variables for a code location
+
+:::note
+  To set environment variables, you need <a href="/dagster-plus/account/managing-users"> one of the following user roles</a> in Dagster+:
+  <ul>
+    <li>Organization Admin, or</li>
+    <li>
+      Editor or Admin. <strong>Note:</strong> Editors and Admins can only set
+      environment variables in full deployments where you're an Editor or Admin.
+    </li>
+  </ul>
+:::
+
+Setting environment variables for specific code locations is accomplished by adding them to your agent's configuration in your project's [`dagster_cloud.yaml` file](/dagster-plus/deployment/management/settings/). The `container_context` property in this file sets the variables in the agent's environment.
+
+**Note**: This approach is functionally the same as [setting environment variables using the Dagster+ UI](/dagster-plus/deployment/management/environment-variables/dagster-ui).
+
+How `container_context` is configured depends on the agent type. Click the tab for your agent type to view instructions.
+
+<Tabs>
+  <TabItem value="Amazon ECS">
+
+### Amazon ECS agents
+
+Using the `container_context.ecs.env_vars` and `container_context.ecs.secrets` properties, you can configure environment variables and secrets for a specific code location.
+
+```yaml
+# dagster_cloud.yaml
+
+locations:
+  - location_name: cloud-examples
+    image: dagster/dagster-cloud-examples:latest
+    code_source:
+      package_name: dagster_cloud_examples
+    container_context:
+      ecs:
+        env_vars:
+          - DATABASE_NAME=testing
+          - DATABASE_PASSWORD
+        secrets:
+          - name: "MY_API_TOKEN"
+            valueFrom: "arn:aws:secretsmanager:us-east-1:123456789012:secret:FOO-AbCdEf:token::"
+          - name: "MY_PASSWORD"
+            valueFrom: "arn:aws:secretsmanager:us-east-1:123456789012:secret:FOO-AbCdEf:password::"
+        secrets_tags:
+          - "my_tag_name"
+```
+
+| Key                                  | Description                                                                                                                                                                        |
+|--------------------------------------|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+| `container_context.ecs.env_vars`     | A list of keys or key-value pairs. If a value is not specified, it pulls from the agent task. E.g., `FOO_ENV_VAR` = `foo_value`, `BAR_ENV_VAR` = agent task value. |
+| `container_context.ecs.secrets`      | Individual secrets using the [ECS API structure](https://docs.aws.amazon.com/AmazonECS/latest/APIReference/API_Secret.html).                                                       |
+| `container_context.ecs.secrets_tags` | A list of tag names; secrets tagged with these in AWS Secrets Manager will be environment variables. The variable name is the secret name, the value is the secret's value.  |
+
+After you've modified `dagster_cloud.yaml`, redeploy the code location in Dagster+ to apply the changes:
+
+!["Highlighted Redeploy option in the dropdown menu next to a code location in Dagster+"](/images/dagster-cloud/developing-testing/code-locations/redeploy-code-location.png)
+
+</TabItem>
+<TabItem value="Docker">
+
+### Docker agents
+
+Using the `container_context.docker.env_vars` property, you can include environment variables and secrets in the Docker container associated with a specific code location. For example:
+
+```yaml
+# dagster_cloud.yaml
+locations:
+  - location_name: cloud-examples
+    image: dagster/dagster-cloud-examples:latest
+    code_source:
+      package_name: dagster_cloud_examples
+    container_context:
+      docker:
+        env_vars:
+          - DATABASE_NAME
+          - DATABASE_USERNAME=hooli_testing
+```
+
+The `container_context.docker.env_vars` property is a list, where each item can be either `KEY` or `KEY=VALUE`. If only `KEY` is specified, the value will be pulled from the local environment.
+
+After you've modified `dagster_cloud.yaml`, redeploy the code location in Dagster+ to apply the changes:
+
+![Highlighted Redeploy option in the dropdown menu next to a code location in Dagster+](/images/dagster-cloud/developing-testing/code-locations/redeploy-code-location.png)
+
+</TabItem>
+<TabItem value="Kubernetes">
+
+### Kubernetes agents
+
+Using the `container_context.k8s.env_vars` and `container_context.k8s.env_secrets` properties, you can specify environment variables and secrets for a specific code location. For example:
+
+```yaml
+# dagster_cloud.yaml
+
+locations:
+  - location_name: cloud-examples
+    image: dagster/dagster-cloud-examples:latest
+    code_source:
+      package_name: dagster_cloud_examples
+    container_context:
+      k8s:
+        env_vars:
+          - database_name        # value pulled from agent's environment
+          - database_username=hooli_testing
+        env_secrets:
+          - database_password
+```
+
+ | Key           | Description                                                                                                                                                                                                                                                                                                                                              |
+ |---------------|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
+ | `env_vars`    | A list of environment variable names to inject into the job, formatted as <code>KEY</code> or <code>KEY=VALUE</code>. If only <code>KEY</code> is specified, the value will be pulled from the current process.                                                                                                                                          |
+ | `env_secrets` | A list of secret names, from which environment variables for a job are drawn using <code>envFrom</code>. Refer to the <a href="https://kubernetes.io/docs/tasks/inject-data-application/distribute-credentials-secure/#configure-all-key-value-pairs-in-a-secret-as-container-environment-variables">Kubernetes documentation</a> for more info. |
+
+
+After you've modified `dagster_cloud.yaml`, redeploy the code location in Dagster+ to apply the changes:
+
+![Highlighted Redeploy option in the dropdown menu next to a code location in Dagster+](/images/dagster-cloud/developing-testing/code-locations/redeploy-code-location.png)
+
+</TabItem>
+</Tabs>
+
+## Setting environment variables for full deployments
+
+:::note
+  If you're a Dagster+ <a href="/dagster-plus/account/managing-users"> <strong>Editor</strong> or
+  <strong>Admin</strong> </a> , you can only set environment variables for full deployments where
+  you're an <strong> Editor
+  </strong> or <strong>Admin</strong>.
+:::
+
+Setting environment variables for a full deployment will make the variables available for all code locations in the full deployment. Using this approach will pull variable values from your user cluster, bypassing Dagster+ entirely.
+
+Click the tab for your agent type to view instructions.
+
+<Tabs>
+  <TabItem value="Amazon ECS">
+
+### Amazon ECS agents
+
+To make environment variables accessible to a full deployment with an Amazon ECS agent, you'll need to modify the agent's CloudFormation template as follows:
+
+1. Sign in to your AWS account.
+
+2. Navigate to **CloudFormation** and open the stack for the agent.
+
+3. Click **Update**.
+
+4. Click **Edit template in designer**.
+
+5. In the section that displays, click **View in Designer**. The AWS template designer will display.
+
+6. In the section displaying the template YAML, locate the `AgentTaskDefinition` section:
+
+   ![Highlighted AgentTaskDefinition section of the AWS ECS agent CloudFormation template in the AWS Console](/images/dagster-cloud/developing-testing/environment-variables/aws-ecs-cloudformation-template.png)
+
+
+7. In the `user_code_launcher.config` portion of the `AgentTaskDefinition` section, add the environment variables as follows:
+
+   ```yaml
+   user_code_launcher:
+     module: dagster_cloud.workspace.ecs
+     class: EcsUserCodeLauncher
+     config:
+       cluster: ${ConfigCluster}
+       subnets: [${ConfigSubnet}]
+       service_discovery_namespace_id: ${ServiceDiscoveryNamespace}
+       execution_role_arn: ${TaskExecutionRole.Arn}
+       task_role_arn: ${AgentRole}
+       log_group: ${AgentLogGroup}
+       env_vars:
+         - SNOWFLAKE_USERNAME=dev
+         - SNOWFLAKE_PASSWORD       ## pulled from agent environment
+   ' > $DAGSTER_HOME/dagster.yaml && cat $DAGSTER_HOME/dagster.yaml && dagster-cloud agent run"
+   ```
+
+8. When finished, click the **Create Stack** button:
+
+   ![Highlighted Create Stack button in the AWS Console](/images/dagster-cloud/developing-testing/environment-variables/aws-ecs-save-template.png)
+
+9. You'll be redirected back to the **Update stack** wizard, where the new template will be populated. Click **Next**.
+
+10. Continue to click **Next** until you reach the **Review** page.
+
+11. Click **Submit** to update the stack.
+
+</TabItem>
+<TabItem value="Docker">
+
+### Docker agents
+
+To make environment variables accessible to a full deployment with a Docker agent, you'll need to modify your project's `dagster.yaml` file.
+
+In the `user_code_launcher` section, add an `env_vars` property as follows:
+
+```yaml
+# dagster.yaml
+
+user_code_launcher:
+  module: dagster_cloud.workspace.docker
+  class: DockerUserCodeLauncher
+  config:
+    networks:
+      - dagster_cloud_agent
+    env_vars:
+      - SNOWFLAKE_PASSWORD # value pulled from agent's environment
+      - SNOWFLAKE_USERNAME=dev
+```
+
+In `env_vars`, specify the environment variables as keys (`SNOWFLAKE_PASSWORD`) or key-value pairs (`SNOWFLAKE_USERNAME=dev`). If only `KEY` is provided, the value will be pulled from the agent's environment.
+
+</TabItem>
+<TabItem value="Kubernetes">
+
+### Kubernetes agents
+
+To make environment variables available to a full deployment with a Kubernetes agent, you'll need to modify and upgrade the Helm chart's `values.yaml`.
+
+1. In `values.yaml`, add or locate the `workspace` value.
+
+2. Add an `envVars` property as follows:
+
+   ```yaml
+   # values.yaml
+
+   workspace:
+     envVars:
+       - SNOWFLAKE_PASSWORD # value pulled from agent's environment
+       - SNOWFLAKE_USERNAME=dev
+   ```
+
+3. In `envVars`, specify the environment variables as keys (`SNOWFLAKE_PASSWORD`) or key-value pairs (`SNOWFLAKE_USERNAME=dev`). If only `KEY` is provided, the value will be pulled from the local (agent's) environment.
+
+4. Upgrade the Helm chart.
+
+</TabItem>
+</Tabs>