Amazon EC2 Dedicated Hosts and AWS License Manager are the two AWS features most often used to keep bring-your-own licenses countable on AWS. A Dedicated Host “is a physical server that is fully dedicated for your use”; it allows customers to use “existing per-socket, per-core, or per-VM software licenses” such as Windows Server, SQL Server, SUSE Linux Enterprise Server and Red Hat Enterprise Linux, subject to the license terms.[1] License Manager records the customer’s license terms as rules and tracks consumption “based on virtual cores (vCPUs), physical cores, sockets, or number of machines” across AWS Regions and accounts.[7] Neither feature grants any software license: when customers bring their own license, “you are responsible for managing your own licenses.”[6]
Editions
EC2 offers three tenancies. Default tenancy instances run on shared hardware where “multiple AWS accounts might share the same physical hardware.”[2] The two dedicated options differ as follows:[1]
| Attribute | Dedicated Host | Dedicated Instance |
|---|---|---|
| Dedicated physical server | Physical server with instance capacity fully dedicated to your use | Physical server dedicated to a single customer account |
| Billing | Per host | Per instance |
| Visibility of sockets, cores and host ID | Number of sockets and physical cores visible | None |
| Host and instance affinity | Supported | Not supported |
| Targeted instance placement | Supported | Not supported |
| Bring your own license | Supported | Partial: SQL Server with License Mobility through Software Assurance, and Windows VDA licenses |
| Capacity Reservations | Not supported | Supported |
Dedicated Instances “might share hardware with other instances from the same AWS account that are not Dedicated Instances”, and if a Dedicated Instance is stopped and started “it might not run on the same host.”[2] AWS states there are no performance, security or physical differences between the two.[1] The rule Dedicated Hosts expose sockets and physical cores records the comparison.
License Manager covers several functions: self-managed licenses (customer-defined rules), license asset groups across accounts, seller-issued and granted licenses for AWS Marketplace and ISVs, license type conversions, inventory search for on-premises servers through AWS Systems Manager, user-based subscriptions and Linux subscription tracking.[7] “There is no additional charge for AWS License Manager.”[11]
Metrics
A License Manager self-managed license has a license type, “The metric used to count licenses”, with the values vCPUs, Cores, Sockets and Instances.[8] These are recorded as the catalog metrics vCPU, Cores, Sockets and Instances. Physical cores and sockets are only meaningful on Dedicated Hosts: the EC2 describe-hosts API and License Manager report “the number of sockets and physical cores on a Dedicated Host.”[5] The host itself is billed as a Dedicated Host, whatever runs on it.[3]
Counting / floors
Rules available in License Manager
The rules a self-managed license can carry depend on the counting type:[8]
| Rule | API name | Available for |
|---|---|---|
| License affinity to host (1 to 180 days) | licenseAffinityToHost | Cores, Sockets |
| Minimum / maximum cores | minimumCores / maximumCores | Cores, Sockets |
| Minimum / maximum sockets | minimumSockets / maximumSockets | Cores, Sockets |
| Minimum / maximum vCPUs | minimumVcpus / maximumVcpus | Instances, vCPUs |
| Tenancy | allowedTenancy | All |
| vCPU Optimization | honorVcpuOptimization | vCPUs |
| Include stopped instances | includedStoppedInstances | All |
“Dedicated Hosts are required if the counting type is Cores or Sockets”, whereas shared tenancy, Dedicated Hosts and Dedicated Instances are all supported for Instances or vCPUs.[8] After a host affinity period elapses, the license is available for reuse within 24 hours.[8] With vCPU Optimization set, License Manager counts the customized core and thread count set through EC2 CPU options rather than the instance type’s default vCPUs.[8][16] See the rule Cores and Sockets require Dedicated Hosts.
Enforcement and release
Rules are attached to AMIs, launch templates or CloudFormation templates. “When a hard limit is reached, License Manager blocks additional instance launches. When a soft limit is reached, License Manager notifies you”.[9] Tracking runs from when rules are attached until the instance is terminated. By default a stopped instance’s license is released back to the pool; setting Include stopped instances keeps it counted, “useful when your licensing terms require that licenses remain allocated to instances regardless of their running state.”[9] License Manager “does not support cross-Region instance tracking”: copying an AMI that carries license configurations to another Region causes License Manager to block all launches from the copy.[9] A single resource can carry at most 10 self-managed licenses, and a Region at most 25, under the default service quotas.[17]
Dedicated Host billing
On-Demand Dedicated Hosts are billed “per second (with a minimum of 60 seconds) for active Dedicated Host, regardless of the quantity or the size of instances that you choose to launch on it.”[3] Bringing Windows Server or SQL Server licenses adds no software charge; alternatively Amazon-provided Windows Server AMIs cost $0.046 per hour per vCPU in every Region, so an r5.large (2 vCPUs) adds $0.092 per hour to the host charge.[4] Dedicated Instances carry a charge of “$2/hour in every Region you have at least one Dedicated Instance running”, which Savings Plans do not discount.[15]
Virtualization & partitioning
Dedicated Hosts give the physical-host evidence that per-core and per-socket licenses usually require. Host affinity means an instance “will only run on a specific Dedicated Host”, and targeted placement lets customers launch onto a chosen host; AWS positions these as the way to monitor Microsoft rules that a license cannot move to another region or physical machine for at least 90 days.[12] Host resource groups can separate hosts “by purpose (for example, dev/test versus production), organizational unit, or license constraint.”[5] Nitro-based host families can run different instance sizes of the same family on one host to improve utilization of hosts and licenses.[5] If a physical server is replaced, “the Dedicated Host will be given a new host-ID”, which matters for licenses tied to a physical machine.[5]
AWS Config can record Dedicated Host configuration changes, including instance and AMI IDs paired with host ID and socket and core counts, as a data source for license reporting.[12][6] For the vendor-side meaning of hard and soft partitioning, see Virtualization and partitioning.
Cloud / BYOL
The general BYOL procedure on Dedicated Hosts is to verify that the license terms allow use “in a virtualized cloud environment”, import the machine image with VM Import/Export, and launch it onto hosts in the account; imported Windows AMIs cannot be activated against the Amazon Windows KMS server.[6] RHEL and SUSE Linux on Dedicated Hosts require the customer’s own AMIs, because “You can’t use the RHEL and SUSE Linux AMIs that are offered by AWS or that are available on AWS Marketplace with Dedicated Hosts”, except on high-memory hosts.[1] Amazon RDS instances are not supported on Dedicated Hosts.[1] For Microsoft software, the Service Terms require Dedicated Instances or Dedicated Hosts under the BYOL Program unless the Microsoft agreement provides otherwise.[13]
License Manager integrates with Amazon RDS for Oracle and RDS for Db2 BYOL, tracking engine editions and packs by vCPU; discovery of Oracle DB instances can take up to 24 hours.[14] It can also track servers outside AWS through AWS Systems Manager.[7]
Audits
AWS’s documentation is explicit that “AWS does not participate in the audit process with software vendors. Customers are responsible for compliance and assume the responsibility of carefully understanding and capturing rules into License Manager based on their licensing agreements.”[9] The FAQ adds that License Manager dashboards can be used “in vendor audits”, while repeating that AWS cannot participate in them.[10] AWS states that it does not have access to license-tracking data, which remains in the customer’s account.[9] License Manager output is therefore customer evidence, not vendor-accepted evidence; see Software license audit and Effective license position.
Programs
Dedicated Host Reservations provide “a discount of up to 70 percent compared to On-Demand Dedicated Host pricing” and require active hosts before purchase.[1] A reservation covers hosts of one instance family in one Availability Zone, applies to the family rather than instance size, and a host associated with a reservation “can’t be released until the reservation’s term is over.”[3] Reservations are noncancellable and nonrefundable, and Dedicated Hosts are nontransferable (Service Terms 5.4.2).[13] Savings Plans can also apply to Dedicated Host usage, except for the u-6tb1 to u-24tb1 high-memory hosts.[3] See AWS Savings Plans and Reserved Instances.
Out of scope
This article does not cover per-family On-Demand Dedicated Host rates (rendered client-side on the AWS pricing page and not captured), instance capacity per host type, Amazon EVS or AWS Outposts, License Manager seller-issued licenses from the ISV side, or any vendor’s rules on which counting type applies.