Amazon EC2 Dedicated Instances

By default, EC2 instances run on shared tenancy hardware. This means that multiple AWS accounts might share the same physical hardware.

Dedicated Instances are EC2 instances that run on hardware that's dedicated to a single AWS account. This means that Dedicated Instances are physically isolated at the host hardware level from instances that belong to other AWS accounts, even if those accounts are linked to a single payer account. However, Dedicated Instances might share hardware with other instances from the same AWS account that are not Dedicated Instances.

Dedicated Instances provide no visibility or control over instance placement, and they do not support host affinity. If you stop and start a Dedicated Instance, it might not run on the same host. Similarly, you cannot target a specific host on which to launch or run an instance. Additionally, Dedicated Instances provide limited support for Bring Your Own License (BYOL).

If you require visibility and control over instance placement and more comprehensive BYOL support, consider using a Dedicated Host instead. Dedicated Instances and Dedicated Hosts can both be used to launch Amazon EC2 instances onto dedicated physical servers. There are no performance, security, or physical differences between Dedicated Instances and instances on Dedicated Hosts. However, there are some key differences between them. The following table highlights some of the key differences between Dedicated Instances and Dedicated Hosts:

	Dedicated Host	Dedicated Instance
Dedicated physical server	Physical server with instance capacity fully dedicated to your use.	Physical server that's dedicated to a single customer account.
Instance capacity sharing	Can share instance capacity with other accounts.	Not supported
Billing	Per-host billing	Per-instance billing
Visibility of sockets, cores, and host ID	Provides visibility of the number of sockets and physical cores	No visibility
Host and instance affinity	Allows you to consistently deploy your instances to the same physical server over time	Not supported
Targeted instance placement	Provides additional visibility and control over how instances are placed on a physical server	Not supported
Automatic instance recovery	Supported. For more information, see Amazon EC2 Dedicated Host recovery.	Supported
Bring Your Own License (BYOL)	Supported	Partial support *
Capacity Reservations	Not supported	Supported

* Microsoft SQL Server with License Mobility through Software Assurance, and Windows Virtual Desktop Access (VDA) licenses can be used with Dedicated Instance.

For more information, see Amazon EC2 Dedicated Hosts.

Contents

• Dedicated Instance basics

• Supported features

• Dedicated Instances limitations

• Pricing for Dedicated Instances

• Launch Dedicated Instances

• Change the tenancy of an instance

• Change the tenancy of a VPC

Dedicated Instance basics

A VPC can have a tenancy of either default or dedicated. By default, your VPCs have default tenancy and instances launched into a default tenancy VPC have default tenancy. To launch Dedicated Instances, do the following:

• Create a VPC with a tenancy of dedicated, so that all instances in the VPC run as Dedicated Instances. For more information, see Launch Dedicated Instances into a VPC with default tenancy.

• Create a VPC with a tenancy of default and manually specify a tenancy of dedicated for the instances to run as Dedicated Instances. For more information, see Launch Dedicated Instances into a VPC with default tenancy.

Supported features

Dedicated Instances support the following features and AWS service integrations:

Reserved Instances

To reserve capacity for your Dedicated Instances, you can purchase Dedicated Reserved Instances or Capacity Reservations. For more information, see Reserved Instances for Amazon EC2 overview and Reserve compute capacity with EC2 On-Demand Capacity Reservations.

When you purchase a Dedicated Reserved Instance, you are purchasing the capacity to launch a Dedicated Instance at a much reduced usage fee; the price break in the usage charge applies only if you launch an instance with dedicated tenancy. When you purchase a Reserved Instance with default tenancy, it applies only to a running instance with default tenancy; it does not apply to a running instance with dedicated tenancy.

You can't use the modification process to change the tenancy of a Reserved Instance after you've purchased it. However, you can exchange a Convertible Reserved Instance for a new Convertible Reserved Instance with a different tenancy.

Automatic scaling

You can use Amazon EC2 Auto Scaling to launch Dedicated Instances. For more information, see Create a launch template using advanced settings in the Amazon EC2 Auto Scaling User Guide.

Automatic recovery

You can configure automatic recovery for a Dedicated Instance if it becomes impaired due to an underlying hardware failure or a problem that requires AWS involvement to repair. For more information, see Automatic instance recovery.

Dedicated Spot Instances

You can run a Dedicated Spot Instance by specifying a tenancy of dedicated when you create a Spot Instance request. For more information, see Launch on single-tenant hardware.

Burstable performance instances

You can leverage the benefits of running on dedicated tenancy hardware with Burstable performance instances. T3 Dedicated Instances launch in unlimited mode by default, and they provide a baseline level of CPU performance with the ability to burst to a higher CPU level when required by your workload. The T3 baseline performance and ability to burst are governed by CPU credits. Because of the burstable nature of the T3 instance types, we recommend that you monitor how your T3 instances use the CPU resources of the dedicated hardware for the best performance. T3 Dedicated Instances are intended for customers with diverse workloads that display random CPU behavior, but that ideally have average CPU usage at or below the baseline usages. For more information, see Key concepts for burstable performance instances.

Amazon EC2 has systems in place to identify and correct variability in performance. However, it is still possible to experience short-term variability if you launch multiple T3 Dedicated Instances that have correlated CPU usage patterns. For these more demanding or correlated workloads, we recommend using M5 or M5a Dedicated Instances rather than T3 Dedicated Instances.

Dedicated Instances limitations

Keep the following in mind when using Dedicated Instances:

• Some AWS services or their features are not supported with a VPC with the instance tenancy set to dedicated. Refer to the respective service's documentation to confirm if there are any limitations.

• Some instance types can't be launched into a VPC with the instance tenancy set to dedicated. For more information about supported instance types, see Amazon EC2 Dedicated Instances.

• When you launch a Dedicated Instance backed by Amazon EBS, the EBS volume doesn't run on single-tenant hardware.

Pricing for Dedicated Instances

Pricing for Dedicated Instances is different from pricing for On-Demand Instances. For more information, see the Amazon EC2 Dedicated Instances.