Create instance

For Linux,

• Use the user_data field to provide a cloud-init script in base64 to apply configurations to the instance.
• Specify the username and password to create a new user.
• When only password is provided, it is set as the password for the default user of the image.
• The user_data is ignored when the password is specified. For Windows,
• Use the user_data field to provide a cloudbase-init script in base64 to create new users on Windows.
• Use the password field to set the password for the ‘Admin’ user on Windows.
• The password of the Admin user cannot be updated via user_data.
• The username cannot be specified in the request.