How to detect the compute owner in Azure ML startup script to back up local folders to CloudFiles

In Azure Machine Learning, the compute instances run under the azureuser, and there is no direct way to programmatically detect the owner of the compute instance using environment variables like $USER. However, you can implement a naming convention or use specific environment variables to manage your backup process effectively.

Suggested Approach:

1. Use Environment Variables: You can utilize the environment variables that are available in the Azure ML compute instance. For instance, you can define a specific environment variable that indicates the compute instance name or owner when the instance is created. This can be set in the startup script or through the Resource Manager template.
2. Script Logic: In your startup script, you can then refer to this environment variable to determine the correct destination folder in CloudFiles. For example, if you set an environment variable COMPUTE_NAME to the name of the compute instance, you can use it in your script to construct the path for the backup:

      #!/bin/bash
      # Assuming COMPUTE_NAME is set to the name of the compute instance
      DESTINATION_FOLDER=/home/azureuser/cloudfiles/code/Users/$COMPUTE_NAME
      # Copy local folders to the destination
      cp -r /home/azureuser/local_folder $DESTINATION_FOLDER
   

3. Resource Manager Template: When provisioning the compute instances, you can include the setup script in the Resource Manager template, which allows you to pass the necessary parameters, including the compute instance name, to the startup script.
4. Backup Logic: Ensure that your backup logic handles the copying of files efficiently and checks for existing files to avoid overwriting.

By using a combination of environment variables and a structured approach in your startup scripts, you can effectively manage the backup of local folders to the appropriate user folders in CloudFiles.

References:

• Customize the compute instance with a script
• Use the script in a Resource Manager template