Set your required Block Reservation Duration in Hours here, with 0 or null indicating that you do not want a block reservation. Amazon EC2 does not terminate Spot Instances with a specified duration (also known as Spot blocks) when the Spot price changes. This makes them ideal for jobs that take a finite time to complete, such as batch processing, encoding and rendering, modeling and analysis, and continuous integration. You can specify a duration of 0, 1, 2, 3, 4, 5, or 6 hours Find more information on Spot Blocks here.