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Amazon Elastic Compute Cloud
User Guide for Linux Instances

Dedicated Hosts

An Amazon EC2 Dedicated Host is a physical server with EC2 instance capacity fully dedicated to your use. Dedicated Hosts allow you to use your existing per-socket, per-core, or per-VM software licenses, including Microsoft Windows Server, Microsoft SQL Server, SUSE, Linux Enterprise Server, and so on.

Contents

Differences between Dedicated Hosts and Dedicated Instances

Dedicated Hosts and Dedicated instances can both be used to launch Amazon EC2 instances onto physical servers that are dedicated for your use.

There are no performance, security, or physical differences between Dedicated instances and instances on Dedicated Hosts. However, Dedicated Hosts give you additional visibility and control over how instances are placed on a physical server.

When you use Dedicated Hosts, you have control over instance placement on the host using the Host Affinity and Instance Auto-placement settings. With Dedicated Instances, you don't have control over which host your instance launches and runs on. If your organization wants to use AWS, but has an existing software license with hardware compliance requirements, this allows visibility into the host's hardware so you can meet those requirements.

For more information about the differences between Dedicated Hosts and Dedicated instances, see Amazon EC2 Dedicated Hosts.

For more information about working with Dedicated Hosts and Dedicated instances, see Modifying Instance Tenancies.

Pricing and Billing

On-Demand Dedicated Hosts

On-Demand billing is automatically activated when you allocate a Dedicated Host to your account.

You are billed an hourly On-Demand rate. Rates vary based on the instance type that the Dedicated Host supports and the region in which the Dedicated Host is running. The instance type size or the number of instances that are running on the Dedicated Host do not have an impact on the cost of the host.

To terminate On-Demand billing, you must first stop instances running on the Dedicated Host and then release it. For more information, see Managing and Releasing Dedicated Hosts.

Dedicated Host Reservations

Dedicated Host Reservations provide a billing discount compared to running On-Demand Dedicated Hosts. Reservations are available in three payment options:

  • No Upfront—No Upfront Reservations provide you with a discount on your Dedicated Host usage over a term and do not require an upfront payment. Available for a one-year term only.

  • Partial Upfront—A portion of the reservation must be paid upfront and the remaining hours in the term are billed at a discounted rate. Available in one and three-year terms.

  • All Upfront—Provides the lowest effective price. Available in one and three-year terms and covers the entire cost of the term upfront, with no additional charges going forward.

You must have an active Dedicated Host in your account before you can purchase reservations. Each reservation covers a single, specific Dedicated Host in your account. The instance family and region of the reservation must match that of the Dedicated Host you want it to cover.

Note

When a Dedicated Host is covered by a reservation, it can't be released until the term is over. However, the reservation can be reassigned to another Dedicated Host in your account, provided the region and instance family match that of the reservation. Contact Support, or your account manager, for information.

Purchasing Dedicated Host Reservations

You can purchase reservations either by emailing your account manager or by logging a Support request. In both instances, you need to provide a CSV or XLS file with the following information:

  • Account ID—The account ID.

  • Host IDs—The Dedicated Host to cover with a reservation. You can obtain the host ID in the AWS Management Console, or by using the DescribeHosts API operation.

  • Region—The region in which the Dedicated Host is running.

  • Instance type—The instance type on the Dedicated Host.

  • Term—One or three years. (One year terms are the only option for No Upfront Dedicated Host Reservations).

  • Payment option—The reservation payment option (No Upfront, Partial Upfront, or All Upfront).

The following table is an example of the request format.

Account IDHost IDRegionInstance TypeTermPayment Option
12345768h-068984f7c97us-east-1C43 yearsAll Upfront

To purchase a reservation using the Support console

  1. Open a Support ticket.

  2. Choose Account and Billing Support, enter the following values:

    • Service—Billing

    • Category—Other Billing Questions

    • Subject—Dedicated Host Reservation Purchase

  3. Provide the information listed in the table above.

  4. Choose Submit.

You will be contacted by Support, or your account manager, when your order has been processed. It can take up to 24 hours for the reduced hourly rate to appear in the Billing & Cost Management page in the AWS Management Console.

For other Dedicated Host Reservation support requirements, contact Support or your account manager.

For more information, see Dedicated Hosts Pricing.

Dedicated Hosts Limitations and Restrictions

Before you allocate Dedicated Hosts, take note of the following limitations and restrictions.

  • Non-BYOL RHEL, SUSE Linux, or Windows AMIs offered by AWS or on the AWS Marketplace cannot be used with Dedicated Hosts.

  • Up to two On-Demand Dedicated Hosts per instance family, per region can be allocated. It is possible to request a limit increase: Request to Raise Allocation Limit on Amazon EC2 Dedicated Hosts.

  • The instances that run on a Dedicated Host can only be launched in a VPC.

  • Host limits are independent from instance limits. Instances that you are running on Dedicated Hosts do not count towards your instance limits.

  • Auto Scaling groups are not supported.

  • Amazon RDS instances are not supported.

  • The AWS Free Usage tier is not available for Dedicated Hosts.

  • Instance placement control refers to managing instance launches onto Dedicated Hosts. Placement groups are not supported for Dedicated Hosts.

Dedicated Host Configurations

Dedicated Hosts are configured to support a single instance type and size capacity. The number of instances you can launch onto a Dedicated Host depends on the instance type that the Dedicated Host is configured to support. For example, if you allocated a c3.xlarge Dedicated Host, you'd have the right to launch up to 8 c3.xlarge instances on the Dedicated Host. To determine the number of instance type sizes that you can run on a particular Dedicated Host, see Supported Instance Types.

Supported Instance Types

Each Dedicated Host supports a single instance size and type (for example, c3.xlarge). It is possible to modify the tenancy of a running instance to host but it must be a supported instance type.

Host typeSocketsPhysical CoresInstance Capacity
c3.large22016
c3.xlarge2208
c3.2xlarge2204
c3.4xlarge2202
c3.8xlarge2201
c4.large22016
c4.xlarge2208
c4.2xlarge2204
c4.4xlarge2202
c4.8xlarge2201
    
g2.2xlarge2204
g2.8xlarge2201
    
m3.medium22032
m3.large22016
m3.xlarge2208
m3.2xlarge2204
    
d2.xlarge2248
d2.2xlarge2244
d2.4xlarge2242
d2.8xlarge2241
    
r3.large22016
r3.xlarge2208
r3.2xlarge2204
r3.4xlarge2202
r3.8xlarge2201
    
m4.large22422
m4.xlarge22411
m4.2xlarge2245
m4.4xlarge2242
m4.10xlarge2241
    
i2.xlarge2208
i2.2xlarge2204
i2.4xlarge2202
i2.8xlarge2201