Q: What are EC2 Dedicated Hosts?
A: Amazon EC2 Dedicated Hosts ("Dedicated Hosts" or "hosts") are physical servers with EC2 instance capacity fully dedicated for your use. Dedicated Hosts support different configurations (physical cores, sockets and VCPUs) which allow you to select and run instances of different families and sizes depending on your business need.
Q: How do Dedicated Hosts differ from bare-metal offering?
A: Dedicated Hosts have pre-installed virtualization software (Xen or Nitro Hypervisor) whereas bare metal servers do not have pre-installed virtualization software. Bare-metal servers are meant for customers who wish to use their own hypervisor or for applications that need to run in non-virtualized environments.
Q: What are the benefits of using Dedicated Hosts?
A: Dedicated Hosts allow you to use your eligible per-socket, per-core, or per-VM software licenses, including Windows Server, SQL Server, SUSE Linux Enterprise Server, Red Hat Enterprise Linux, or other software licenses, that are bound to VMs, sockets, or physical cores, subject to your license terms. This helps you to reduce costs by leveraging your existing investments. Dedicated Hosts also serve as an option when your organization is looking to run certain applications on a single tenant infrastructure to meet any specific corporate compliance and regulatory requirements. Dedicated Hosts is integrated with AWS License Manager to help you track license usage, and automate host management tasks such as host allocation, release, and recovery.
Q: How are T3 Dedicated Hosts different from other EC2 Dedicated Hosts?
A: T3 Dedicated Hosts are general-purpose burstable T3 instances that share CPU resources on your allocated host by providing a baseline CPU performance with the ability to burst to a higher level until the instance spends the credits accrued in its CPU credit balance. This enables a single T3 Dedicated Host to support up to 4 times more instances than comparable non-burstable Dedicated Hosts. T3 Dedicated Hosts also support smaller instance sizes such as t3.nano, t3.micro, t3.small, and t3.medium. These smaller instance sizes are suitable for running Microsoft Windows Desktop and Windows Servers, or small and medium databases.
Q: How are T3 Dedicated Hosts different from T3 Dedicated Instances?
A: Both T3 Dedicated Instances and T3 Dedicated Hosts run T3 instances on physical servers dedicated to a single customer. The key difference between a T3 Dedicated Host and a T3 Dedicated Instance is that a T3 Dedicated Host gives you additional visibility and control over how instances are placed on a physical server. T3 Dedicated Hosts offer per host billing and are more suited to run expensive physical core-based BYOL environments such as Microsoft SQL Server and Windows Server. T3 Dedicated Instances on the other hand, offer per instance billing and are appropriate to run per-vCPU, per instance, or per user BYOL software. An additional difference between T3 Dedicated Instance and T3 Dedicated Host is that T3 Dedicated Instances support both Standard mode and Unlimited mode credit configuration option, whereas T3 Dedicated Hosts support T3 instances with only the Standard mode credit configuration option.
Q: Do T3 instances running on T3 Dedicated Hosts have the concept of CPU credits
A: Yes. T3 instances on T3 Dedicated Hosts make use of credits to track how much CPU is used per instance. They use the same credit model as T3 instances on shared tenancy but they do not support surplus credits which are additional credits used when running in Unlimited mode.
Q: Do T3 instances running on T3 Dedicated Hosts support Standard and Unlimited credit configuration modes for CPU bursting?
A: T3 instances running on T3 Dedicated Hosts support the Standard mode of credit configuration, in which an instance can burst above baseline until it uses up all of its earned credits. T3 Dedicated Hosts do not support running T3 instances in Unlimited mode due to limited individual host resources.
Q: What performance should I expect from T3 instances running on T3 Dedicated Host?
A: T3 instances are bound by the resources of a specific Dedicated Host. While most low to moderate CPU utilization T3 instances will burst to a higher CPU level when required, it is possible to experience short term performance variability if multiple T3 instances have correlated high CPU usage patterns. An example of when this can happen is if you are running VDI infrastructure on T3 Dedicated Hosts and a large number of users are logging in at the same time, using a high amount of CPU cycles. For best performance, we recommend that you monitor how your T3 instances use the CPU resources of the dedicated hardware using the metric DedicatedHostCPUUtilization. This new metric will be available in CloudWatch under the EC2 namespace and “Per-Host Metrics” dimension, and will help to determine the CPU utilization on the Dedicated Host.
Using Dedicated Hosts
Q: How do I use Dedicated Hosts?
A: You can start using Dedicated Hosts simply by allocating a host using EC2 Console, API, CLI, and then launching instances into them. Dedicated Hosts typically go through the following stages in their life-cycle:
- Host Allocation: A host becomes accessible after you have allocated it in your AWS account. In order to allocate a host, you can use the AllocateHosts API or allocate-hosts - AWS CLI or use the AWS Management Console.
- Instance placement: To launch instances on any host, you need to specify tenancy of "host" using the RunInstances API or in the AWS Management Console. To launch instances on a specific host, you need to specify the host ID as a target in the AWS Management Console or in the RunInstances API.
- Host Release: If you no longer need to use a host, at first you need to stop or terminate all of the instances running on the host, and then you can release the host using the ReleaseHosts API or the AWS Management Console.
Alternatively, you can automate the host allocation, instance placement, and host release tasks by specifying your Dedicated Host management preferences in AWS License Manager. License Manager helps you to automate license tracking when you bring your own software licenses (viz. Windows and SQL Server licenses) to AWS. It also helps you add your existing Dedicated Hosts to the automated experience.
Q: How do I use AWS License Manager to manage Dedicated Hosts?
A: You can use AWS License Manager to automate the management of the licenses that you bring to EC2 Dedicated Hosts. In order to bring your own licenses (BYOL) to EC2 Dedicated Hosts and automate host management, you need to perform the following steps.
- Step 1: Define licensing rules for software licenses, such as Windows Server and SQL Server, that you want bring to AWS. We recommend that you consult with your own licensing advisors to carefully understand the terms.
- Step 2: Specify your preferences for managing the underlying hosts. For example, you can define how to allocate and release hosts, which licensing rules to use, what instance types are allowed, and whether to turn on host recovery.
- Step 3: (optional) If you want other AWS accounts in your organization to use the available capacity on the hosts, you can share the host management preferences and licensing rules across your organizational accounts.
Once configured, a user in your organization can simply launch BYOL instances just like they would launch instances with AWS-provided licenses, while AWS takes care of common administrative tasks. Most cloud providers offer limited automation for Dedicated Hosts, so administrators have to perform ongoing management tasks such as host allocation, host capacity utilization, and instance placement. In AWS, you can automate the entire management of EC2 Dedicated Hosts using AWS License Manager, and leverage EC2 capabilities such as auto-scaling with Dedicated Hosts.
Q: Can I automate management of my existing Dedicated Hosts?
A: Yes, once you define preferences for managing your Dedicated Hosts in AWS License Manager, you can onboard your existing Dedicated Hosts to the automated management experience with a few simple clicks and let AWS manage them on your behalf.
Q: Are there any additional charges for using AWS License Manager to manage Dedicated Hosts?
A: No, there are no additional charges for using AWS License Manager to manage Dedicated Hosts. You only pay for the Dedicated Hosts that License Manager allocates on your behalf in your AWS account. See Dedicated Hosts pricing for more information.
Q: How many Dedicated Hosts can I allocate in my AWS account?
A: You can allocate Dedicated Hosts based on the limit that is associated with your account. For more information, visit documentation on AWS Service Limits. If you are using automated management, then you can set up license level limits in AWS License Manager.
Dedicated Host Capabilities & Features
Q. What are the capabilities of Dedicated Hosts?
A: Below are the capabilities available in Dedicated Hosts:
- Multiple instance size support - You can run different instance sizes within the same instance family on a Dedicated Host by leveraging the Nitro-based instances. This helps maximize utilization of your Dedicated Host fleet as well as your software licenses. Support for multiple instance types on the same Dedicated Host is available for the instance families listed here.
- Instance placement control - You have the option to launch instances onto a specific Dedicated Host, which helps you meet your compliance requirements.
- Affinity - You have the option to keep instances attached to a host even if you stop and start it, by specifying instance affinity to a particular host.
- Continuous monitoring - You can continuously monitor and record when your instances are getting launched, stopped, or terminated on Dedicated Hosts using AWS Config recording. Continuous monitoring helps you meet your compliance requirements, such as auditing of instances launched into Dedicated Hosts.
- Visibility of sockets and physical cores - You have visibility of the number of sockets and physical cores, which helps you meet licensing obligations of bringing physical core and socket based licenses.
- Integrated license management - You have the option to automate the tracking and management of your software licenses on Dedicated Hosts using AWS License Manager. You can refer to AWS License Manager Documentation for more detail.
- Automated management and auto-scaling - You can automate management of Dedicated Hosts using AWS License Manager, and you can also achieve elasticity on Dedicated Hosts by using Auto-Scaling groups.
- Cross-account sharing - You can share resources between Dedicated Host accounts within your organization or an organizational unit by enabling cross-account sharing.
- Host recovery - You can make instances on Dedicated Hosts more resilient by turning on Host recovery. Host recovery automatically restarts your instances on a new host in the event of an unexpected hardware failure.
Multiple instance size support
Q: How do I know how many instances I can run on each host?
A: The maximum number of instances you can run per host varies based on the instance type configuration you select. You can see the maximum number of instances per host on the Dedicated Host Pricing Page or in the EC2 Dedicated Host console or the DescribeHosts API.
Instance placement control
Q: How do I control instance placement?
A: You have the option to launch instances onto a specific Dedicated Host, or you can let Amazon EC2 place the instances automatically. Controlling instance placement allows you to deploy applications to help address licensing, corporate compliance, and regulatory requirements.
Q: Do I need to place new instances in Dedicated Hosts manually?
A: No, you do not need to place instances manually. You can use AWS License Manager to automate and let AWS manage instance placement on your behalf.
Q. How do I launch instances when I use AWS License Manager to automate placement?
A: You launch instances using AWS License Manager just like you launch instances with Amazon provided licenses. You simply specify the AMI and instance type. Providing tenancy type as “host” is optional while launching instances using AWS License Manager.
Q. Are there any prerequisites for launching instance using AWS License Manager?
A: Yes, in order to launch an instance while using AWS License Manager, you need to attach a host resource group to your license configuration in AWS License Manager and set up license rules so that new instances are launched as per your capacity requirements.
Q: What is a host resource group?
A: A host resource group is a group of Dedicated Hosts that you can manage as a single entity. You can use host resource groups to separate hosts by purpose (for example, dev/test versus production), organizational unit, or license constraint.
Q: How do I manage licenses that have requirements to be attached to one physical server for a certain time period?
A: There are certain scenarios that require the license to remain assigned to the same physical server for a specific period of time. For example Microsoft requires that Windows Server licenses remain assigned to the same physical server for at least 90 days. By using AWS License Manager, you can set License Affinity rules to restrict a license usage for the specified number of days.
Visibility of sockets and physical cores
Q: Can I uniquely identify a Dedicated Host?
A: Yes, you can identify each Dedicated Host using the host-ID. In case an underlying physical server is replaced, the Dedicated Host will be given a new host-ID.
Q: Is the host-ID similar to an asset-ID of a physical server?
A: Yes, a host-ID is similar to an asset-ID of a physical server.
Q: Will AWS reuse the same host-ID for different physical servers?
A: No, AWS will not reuse the same host-ID for different physical servers. Every physical server has a different host-ID. If AWS substitutes your underlying physical server for warranty purposes or for other AWS requirements, you will also get a new host-ID. AWS will not swap physical servers without changing the host-ID.
Integrated license management
Q: How can I track number of sockets and physical cores on Dedicated Hosts?
A: You can use EC2 describe-hosts API to track the number of sockets and physical cores on a Dedicated Host. You can also use AWS License Manager to automate the tracking of sockets and physical cores.
Automatic management and auto-scaling
Q: How do I use auto scaling groups with Dedicated Hosts?
A: You can use Auto Scaling groups (ASG) to launch dedicated hosts into any of your Amazon Virtual Private Clouds (Amazon VPCs). To use ASG, you should create a host resource group in in AWS License Manager. Once you specify your requirements in the host resource group, you can create a launch template and then create an ASG using the launch template.
Q: I use multiple AWS accounts. Can I share Dedicated Hosts across all my accounts?
A: Yes, you can share Dedicated Hosts with all your AWS accounts. You have the flexibility of sharing hosts with a few accounts or with all accounts in your AWS Organizations to save costs.
Q: Does sharing impact the account level limits of Dedicated Hosts?
A: Dedicated Hosts that are shared count towards the owner account’s Dedicated Hosts limits only. The limits of a member account’s Dedicated Hosts are not affected by Dedicated Hosts that have been shared with them. Similarly, instances that members launch onto shared Dedicated Hosts do not count towards their instance limits.
Q: How do I set up host recovery?
A: You can turn on host recovery through the AWS Console, or using a CLI or API. You can enable, disable and view configuration for host recovery configuration for a Dedicated Host at any time. You can also turn on host recovery for a group of Dedicated Hosts using host resource group in AWS License Manager.
Q: Can I run an instance on a host with the EC2 Classic network type?
A: The instances that run on hosts can only be assigned to Amazon Virtual Public Cloud. You cannot run an instance on a host with the EC2 Classic networking type.
Q: Do I need to create new Amazon VPC if I migrate dedicated instances in a dedicated VPC to "host" tenancy?
A: No, both dedicated instances and instances running on hosts can be assigned to a dedicated Amazon VPC.
Dedicated Host Maintenance
Q. Do I need to specify a maintenance window to apply patches to Dedicated Hosts?
A: You are not required to specify a maintenance window. AWS manages the patching of Dedicated Hosts and other EC2 tenancy options automatically.
Dedicated Hosts Pricing
Q: What different licensing options are available on Dedicated Hosts?
A: The following licensing options are available on Dedicated Hosts:
- Bring your own licenses (BYOL) : You can bring your eligible existing per-socket, per-core, or per-VM software licenses, that are bound to VMs, sockets, or physical cores, as well as other types of licenses, subject to your license terms.
- License included (LI) : You can use Windows Server AMIs provided by AWS.
- Amazon Linux : You can use free open source Amazon Linux OS and run any of your workloads on AWS Dedicated Hosts. Dedicated Hosts also supports License Included instances for all Linux OS (including AL, AL2, Ubuntu) except SUSE and RHEL.
- AWS Marketplace AMIs: You can launch all AWS Marketplace AMIs on Dedicated Hosts.
Q. What AMIs can be launched onto Dedicated Hosts?
A: You can use BYOL, Amazon Linux, Windows Server AMIs provided by Amazon, and AWS Marketplace AMIs on Dedicated Hosts.
Q: What are the purchasing options and terms for Dedicated Hosts?
A: AWS provides three different purchasing options to suit your needs and maximize your savings.
- On-Demand: This is a non-commitment based pricing option where you pay for each second (minimum of 60 seconds) that the Dedicated Host is active in your account (or allocated). You can terminate billing for any particular On-Demand Dedicated Host by releasing it and you have the flexibility to scale up or down depending on your requirements.
- Reserved Instances: This is a commitment based pricing option and you can purchase a Reserved Instance for a one-year or three-year commitment, with the three-year commitment offering a bigger discount. There are three payment options: All Upfront, Partial Upfront and No Upfront Reserved Instance. Reserved Instances can provide you with cost savings of up to 70% on your on-demand costs over the term.
- Savings Plans: This is flexible pricing model that offers significant savings over On-Demand in exchange for a commitment to use a specific amount of compute power (measured in $/hour) for a one or three year period. Savings Plans automatically reduce your bills on compute usage across any AWS Region, even as usage changes. This provides you with the flexibility to use any compute option that suits your needs and helps you save up to 72% on your AWS Compute usage.
Q: How am I billed for a host that is running On-Demand instance pricing?
A: For a host that is running On-Demand, you pay for each second (minimum of 60 seconds) that the host is active (or allocated) in your account, regardless of the number of instances, or types of AMIs, that are running on the host. You can terminate billing for any particular On-Demand Dedicated Host by releasing it. On-Demand instance pricing gives you the flexibility to scale up or down without long-term commitments.
Note: License Included (LI) Windows Server on Dedicated Hosts is billed on a per-hour basis.
Q: What are the payment terms and options for Reserved Instances?
A: You pay for Reserved Instances for a one-or-three year term commitment. There are three payment options: all upfront, partial upfront and no upfront.
- All Upfront payment_: You roll the entire cost of your Dedicated Host reservation into one upfront payment. All Upfront reservation provides the best overall price compared to the partial upfront and no upfront offerings.
- Partial Upfront payment: You pay roughly half of the reservation cost upfront. The remaining cost is amortized (and charged hourly) across each hour in the term. The Partial Upfront payment option provides a better price than the no upfront payment option.
- No Upfront payment: You pay nothing upfront and the entire cost of the Reserved Instance is amortized (and charged hourly) across each hour in the term.
You can contact your account manager if you need to reserve Dedicated Hosts for a term which is greater than three years.
Q: How am I billed for a host that is running on Reserved Instances?
A: Reserved Instances can provide up to 70% discount compared to the On-Demand price. When you purchase a Dedicated Host reservation, you are billed for every hour during the entire term that you select, regardless of whether the instances are running or not. The effective hourly price shows the amortized hourly cost of the Dedicated Host reservation (this takes the total cost of the host reservation over the entire term, including any upfront payment, and spreads it out over each hour of the term).
For each month, the actual monthly payment will equal the actual number of hours in that month multiplied by the hourly usage rate. The hourly usage rate is equivalent to the total average monthly payments over the term divided by the total number of hours (based on a 365-day year) over the term.
Q: Can I choose the Reserved Instance option without buying Dedicated Hosts?
A: No, you need to purchase and allocate Dedicated Host to your account in order to choose the Reserved Instance option.
Q: How can I purchase a Reserved Instance for a Dedicated Host?
A: You can purchase a Reserved Instance for Dedicated Host by allocating a certain number of hosts for a time period of one or three years. After you’ve allocated a Dedicated Host to your account, you can pay for a one or three year Reserved Instance for the Dedicated host. When you purchase a Reserved Instance and assign it to the Dedicated Host, you are committing to pay for that Dedicated Host for a minimum period of time equal to the term of the Reserved Instance.
Q: What happens when my Reserved Instance expires?
A: When your Reserved Instance expires, your Dedicated Hosts will remain allocated to your account and you can continue to use the Dedicated Hosts. If you decide to not release the Dedicated Hosts, then you will be billed On-Demand after the expiration of the Reserved Instance. You will also have the option to pay for another Reserved Instance for the same Dedicated Hosts.
Q: What are the pricing terms for Windows Server License (BYOL and LI) on Dedicated Hosts?
A: Subject to Microsoft licensing terms, you can bring your existing eligible Windows Server and SQL Server licenses to Dedicated Hosts. There is no additional charge for software usage if you choose to bring your own licenses.
Alternatively, you can use Windows Server Amazon Machine Images (AMIs) provided by Amazon to run the latest versions of Windows Server on Dedicated Hosts. This is common for scenarios where you have existing SQL Server licenses eligible to run on Dedicated Hosts but need Windows Server to run the SQL Server workload. To get more details about Windows Server AMIs prices refer to Dedicated host pricing page.
Q: What rights do I have to access the equipment on which my Dedicated Hosts are running?
You do not have the right to physically possess or have physical access to any AWS server, equipment, real or personal property, or any other AWS owned assets.