knowledge_base: add direct_engine_migration example

knowledge_base/direct_engine_migration/.gitignore

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+.databricks

knowledge_base/direct_engine_migration/README.md

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+# Direct engine migration
+
+This Declarative Automation Bundles example migrates a serverless job from the Terraform engine to the direct engine.
+
+See the [direct engine documentation](https://docs.databricks.com/dev-tools/bundles/direct).
+
+## Prerequisites
+
+* Databricks CLI v1.19.x for the Terraform deployment. Version 1.20.0 removes the Terraform engine.
+* Databricks CLI v1.20.0 or above for the migration
+
+## Usage
+
+| Engine | Local state | Workspace state |
+| --- | --- | --- |
+| Terraform | `.databricks/bundle/dev/terraform/terraform.tfstate` | `<root_path>/state/terraform.tfstate` |
+| Direct | `.databricks/bundle/dev/resources.json` | `<root_path>/state/resources.json` |
+
+1. Use Databricks CLI v1.19.x to deploy with the Terraform engine.
+
+   ```text
+   DATABRICKS_BUNDLE_ENGINE=terraform databricks bundle deploy
+   ```
+
+2. Record the job ID with the Terraform engine.
+
+   ```text
+   DATABRICKS_BUNDLE_ENGINE=terraform databricks bundle summary --output json
+   ```
+
+3. Upgrade to Databricks CLI v1.20.0 or above. Migrate the local state. `databricks bundle deploy` also migrates the state automatically.
+
+   ```text
+   databricks bundle deployment migrate
+   ```
+
+4. Confirm that the migration plan has zero changes.
+
+   ```text
+   databricks bundle plan
+   ```
+
+5. Deploy and run the job. Confirm that the job ID is unchanged.
+
+   ```text
+   databricks bundle deploy
+   databricks bundle run direct_engine_migration
+   databricks bundle summary --output json
+   ```
+
+6. Confirm that the deployed bundle still has zero changes.
+
+   ```text
+   databricks bundle plan
+   ```
+
+7. Remove the job and workspace files.
+
+   ```text
+   databricks bundle destroy --auto-approve
+   ```

knowledge_base/direct_engine_migration/databricks.yml

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+bundle:
+  name: direct_engine_migration
+
+include:
+  - resources/*.yml
+
+targets:
+  dev:
+    default: true
+    mode: development
+    workspace:
+      root_path: /Workspace/bundle-examples/${bundle.name}/dev/${workspace.current_user.short_name}

knowledge_base/direct_engine_migration/resources/direct_engine_migration.job.yml

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+resources:
+  jobs:
+    direct_engine_migration:
+      name: Direct engine migration
+      tasks:
+        - task_key: hello
+          spark_python_task:
+            python_file: ../src/main.py
+          environment_key: default
+      environments:
+        - environment_key: default
+          spec:
+            environment_version: "6"

knowledge_base/direct_engine_migration/src/main.py

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+print("Hello from the direct engine migration example.")