AWS Documentation » Amazon EC2 » User Guide for Linux Instances » Amazon EC2 Instances » Instance Purchasing Options » Scheduled Reserved Instances

Scheduled Reserved Instances

Scheduled Reserved Instances (Scheduled Instances) enable you to purchase capacity reservations that recur on a daily, weekly, or monthly basis, with a specified start time and duration, for a one-year term. You reserve the capacity in advance, so that you know it is available when you need it. You pay for the time that the instances are scheduled, even if you do not use them.

Scheduled Instances are a good choice for workloads that do not run continuously, but do run on a regular schedule. For example, you can use Scheduled Instances for an application that runs during business hours or for batch processing that runs at the end of the week.

If you require a capacity reservation on a continuous basis, Reserved Instances might meet your needs and decrease costs. For more information, see Reserved Instances. If you are flexible about when your instances run, Spot Instances might meet your needs and decrease costs. For more information, see Spot Instances.

How Scheduled Instances Work

Amazon EC2 sets aside pools of EC2 instances in each Availability Zone for use as Scheduled Instances. Each pool supports a specific combination of instance type, operating system, and network.

To get started, you must search for an available schedule. You can search across multiple pools or a single pool. After you locate a suitable schedule, purchase it.

You must launch your Scheduled Instances during their scheduled time periods, using a launch configuration that matches the following attributes of the schedule that you purchased: instance type, Availability Zone, network, and platform. When you do so, Amazon EC2 launches EC2 instances on your behalf, based on the specified launch specification. Amazon EC2 must ensure that the EC2 instances have terminated by the end of the current scheduled time period so that the capacity is available for any other Scheduled Instances it is reserved for. Therefore, Amazon EC2 terminates the EC2 instances three minutes before the end of the current scheduled time period.

You can't stop or reboot Scheduled Instances, but you can terminate them manually as needed. If you terminate a Scheduled Instance before its current scheduled time period ends, you can launch it again after a few minutes. Otherwise, you must wait until the next scheduled time period.

The following diagram illustrates the lifecycle of a Scheduled Instance.

Service-Linked Roles for Scheduled Instances

Amazon EC2 creates a service-linked role when you purchase a Scheduled Instance. A service-linked role includes all the permissions that Amazon EC2 requires to call other AWS services on your behalf. For more information, see Using Service-Linked Roles in the IAM User Guide.

Amazon EC2 uses the service-linked role named AWSServiceRoleForEC2ScheduledInstances to complete the following actions:

• ec2:TerminateInstances - Terminate Scheduled Instances after their schedules complete

• ec2:CreateTags - Add system tags to Scheduled Instances

If you purchased Scheduled Instances before October 2017, when Amazon EC2 began supporting this service-linked role, Amazon EC2 created the AWSServiceRoleForEC2ScheduledInstances role in your AWS account. For more information, see A New Role Appeared in My Account in the IAM User Guide.

If you no longer need to use Scheduled Instances, we recommend that you delete the AWSServiceRoleForEC2ScheduledInstances role. After this role is deleted from your account, Amazon EC2 will create the role again if you purchase Scheduled Instances.

Purchasing a Scheduled Instance

To purchase a Scheduled Instance, you can use the Scheduled Reserved Instances Reservation Wizard.

Warning

After you purchase a Scheduled Instance, you can't cancel, modify, or resell your purchase.

To purchase a Scheduled Instance using the console

1. Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.

2. In the navigation pane, under INSTANCES, choose Scheduled Instances.

3. Choose Purchase Scheduled Instances.

4. On the Find available schedules page, do the following:

   1. Under Create a schedule, select the starting date from Starting on, the schedule recurrence (daily, weekly, or monthly) from Recurring, and the minimum duration from for duration. Note that the console ensures that you specify a value for the minimum duration that meets the minimum required utilization for your Scheduled Instance (1,200 hours per year).

      

   2. Under Instance details, select the operating system and network from Platform. To narrow the results, select one or more instance types from Instance type or one or more Availability Zones from Availability Zone.

      

   3. Choose Find schedules.

   4. Under Available schedules, select one or more schedules. For each schedule that you select, set the quantity of instances and choose Add to Cart.

   5. Your cart is displayed at the bottom of the page. When you are finished adding and removing schedules from your cart, choose Review and purchase.

5. On the Review and purchase page, verify your selections and edit them as needed. When you are finished, choose Purchase.

To purchase a Scheduled Instance using the AWS CLI

Use the describe-scheduled-instance-availability command to list the available schedules that meet your needs, and then use the purchase-scheduled-instances command to complete the purchase.

Launching a Scheduled Instance

After you purchase a Scheduled Instance, it is available for you to launch during its scheduled time periods.

To launch a Scheduled Instance using the console

1. Open the Amazon EC2 console at https://console.aws.amazon.com/ec2/.

2. In the navigation pane, under INSTANCES, choose Scheduled Instances.

3. Select the Scheduled Instance and choose Launch Scheduled Instances.

4. On the Configure page, complete the launch specification for your Scheduled Instances and choose Review.

   Important

   The launch specification must match the instance type, Availability Zone, network, and platform of the schedule that you purchased.

5. On the Review page, verify the launch configuration and modify it as needed. When you are finished, choose Launch.

To launch a Scheduled Instance using the AWS CLI

Use the describe-scheduled-instances command to list your Scheduled Instances, and then use the run-scheduled-instances command to launch each Scheduled Instance during its scheduled time periods.

Scheduled Instance Limits

Scheduled Instances are subject to the following limits:

• The following are the only supported instance types: C3, C4, C5, M4, and R3.

• The required term is 365 days (one year).

• The minimum required utilization is 1,200 hours per year.

• You can purchase a Scheduled Instance up to three months in advance.