Microsoft Per Core licensing rules
Summarize
Summary of Microsoft Per Core Licensing Rules
The Per Core licensing model allows organizations to license both physical and virtual cores on servers, providing a cost-efficient approach based on the number of rights utilized. Each server must be assigned the appropriate number of core licenses, which varies depending on whether licensing is for a physical server or individual virtual operating system environments (OSE).
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Key Features
- Tracks core packs for Red Hat products and allows imports of entitlements based on license packs.
- Estimates purchased rights based on the formula: Rights Per license pack Number of packs.
- Offers flexibility to create and remove allocations, applicable to VMs or physical hosts.
- Calculates optimal licensing models for physical and virtual cores on each machine.
Key Outcomes
For Enterprise Edition, licensing a physical host covers all its VMs without requiring additional rights for VMs exceeding the number of physical cores. In contrast, the Standard Edition only licenses the physical host, necessitating additional licenses for VMs.
In clustered environments, VMs must be licensed as if they can run on any host in the cluster, potentially multiplying the rights needed. Software Assurance enhances flexibility, allowing license mobility for VMs across hosts. If licenses are allocated to hosts but individual VMs are later licensed, unused rights may be generated. The system optimizes licensing decisions at the cluster level, ensuring efficient usage of rights.
The Per Core license metric licenses cores on both the physical server and the virtual cores that support virtual machines and presents a cost-efficient model based on the number of rights used.
Overview of the Per Core license metric
To license a software under the Per Core licensing model, each server must be assigned an appropriate number of core licenses. The number of core licenses needed depends on whether you are licensing the physical server or individual virtual operating system environment (OSE).
- Provides the ability to track core packs for Red Hat products.
- Provides the ability to import entitlements with rights per license pack and number of packs for Red Hat Core based entitlements​.
- Estimation of Purchased Rights based on Rights Per license pack * Number of packs.
- Offers the option to create and remove allocations based on reconciliation of Red Hat Core based products.
Allocations can be applied to virtual machines (VMs) or to only hosts. Allocations made to a cluster are invalid and become allocated not in use. If allocations are made to physical hosts not part of a cluster, any allocations made to VMs on that host will be allocated not in use. This metric runs calculations for physical cores and virtual cores on each machine and present the most optimal licensing model based on the number of rights used.
Enterprise Edition vs Standard Edition
When entitlements for Enterprise Edition are applied to a physical host, it licenses the physical host and all its VMs. Alternatively, the VMs can be licensed individually. The Per Core calculator will apply the most optimal licensing scheme. Enterprise Edition entitlements with Software Assurance (SA) has the benefit of unlimited virtualization. This means that a host with all its physical cores licensed with Enterprise Edition entitlements does not require additional rights for each VM exceeding the number of physical cores.
When Standard Edition licenses are applied on a physical host, it licenses only the physical host– it does not cover the VMs hosted by the physical. You need additional licenses to cover the VMs.
Per Core licensing in a clustered environment
Virtual machines in a cluster can run on any physical host in the cluster. For example, if a cluster has two hosts (ESX1 and ESX2) and DRS3 determines that ESX1 is overloaded, vMotion4 is used to dynamically move a VM1 from ESX1 to ESX2. Microsoft requires that any VM hosted in a clustered environment must be licensed as if it can be virtualized by any host on the cluster. For example, if a VM in a cluster requires 4 rights, and the cluster has 3 hosts, the rights needed to license that VM is 12 (4 rights x 3 hosts).
A VM locked down by host affinity rules is licensed only for the hosts that it can live on.
A benefit of Software Assurance is license mobility. It allows a VM's license to move to any host in the cluster. This means that if you have an entitlement with SA, you can license the same VM with just 4 rights.
For clusters, the Rights used by (samp_entitlement_result) record specifies the used_by as the VM or host consuming the rights.
In case of entitlements without Software Assurance, clusters may yield suboptimal results because an assumption is made that entitlements have Software Assurance.
Optimization is done at the cluster level. Either all physical hosts in the cluster are licensed or all the VMs in the cluster are individually licensed. A map is created of devices in the cluster (all VMs and all the hosts it can reside on). Allocations are processed and any devices that can be licensed are removed from the map. The optimization (whether to license all VMs or only the physical hosts) is applied to any remaining unlicensed devices in the map.
Allocations can only be made for physical hosts or VMs. Allocations to clusters are ignored. Unallocated rights are utilized if the allocated rights are less than the rights required to license the device. If there aren't enough rights available to license a device in a cluster, the entire cluster is unlicensed and Rights needed by records are generated for the Purchase Rights remediation option. Rights needed by record is generated for each device and the rights needed. If the allocations were made to the host and the license calculator optimization logic decided to license by individual VMs, those rights allocated to the host will be allocated not in use.