Amazon Web Services (AWS) have introduced ‘Scheduled Reserved Instances’, which enables EC2 compute capacity to be reserved at a discounted price for use on a periodic basis. For example, a EC2 instance type can be reserved for daily usage between the hours of 01:00 UTC and 05:00 UTC to perform overnight data analysis, or weekly or monthly to perform compute-intensive calculations.
The new Scheduled Reserved Instances are offered in addition to the existing reserved instances, which have now been renamed as ‘Standard Reserved Instances’. Reserved instances allow an AWS customer to reserve Amazon EC2 computing capacity, specified by instance type, on a fixed-term contract. The reserved instance types can be launched at a discounted price (in comparison with price of On-Demand instances), with the Standard Reserved Instance model providing the discount on the specified instances launched 24x7, and the new Scheduled Reserved providing the discount only during the time window specified.
The AWS blog states that Scheduled Reserved Instances are cost-effective for workloads that run on a daily, weekly, or monthly recurring schedules. Examples of these type of workloads include:
- A bank or mutual fund performs Value at Risk calculations every weekday afternoon.
- A phone company does a multi-day bill calculation run at the start of each month.
- A trucking company optimizes routes and shipments on Monday, Wednesday, and Friday mornings.
- An animation studio performs a detailed, compute-intensive 3D rendering every night.
Scheduled Reserved Instances can only be purchased by searching for and selecting available schedules that match a specified requirement via the AWS Management Console. A requirement can be specified by start time (limited to hourly resolution), a duration (minimum 4 hours), a recurring period (daily, weekly, monthly), the instance platform (linux/Windows), instance type and availability zone. Available schedules that match the specified criteria are displayed with price per hour and quantity available.
The AWS blog states that the new Scheduled Reserved Instance model allows you to reserve instances for predefined blocks of time on a recurring basis for a one-year term, with prices that are generally 5% lower than the equivalent On-Demand rates in peak times, and 10% lower in off-peak hours. Peak hours vary by region, and further information on the specific region peak hours can be found on the AWS EC2 pricing webpage. The fixed-term contract for Scheduled Reserved Instances is currently 1 year.
This feature is available today in the US East (Northern Virginia), US West (Oregon), and Europe (Ireland) regions, with support for the C3, C4, M4, and R3 instance types.
Further information on Scheduled Reserved Instances can be found on the AWS Official Blog and the AWS EC2 Reserved Instances web page.