Chapter 6. Subscriptions

6.1. Subscription offerings

Red Hat OpenShift Container Storage subscription is based on “core-pairs,” similar to Red Hat OpenShift Container Platform. The Red Hat OpenShift Container Storage 2-core subscription is based on the number of logical cores on the CPUs in the system where OpenShift Container Platform runs.

As with OpenShift Container Platform:

  • OpenShift Container Storage subscriptions are stackable to cover larger hosts.
  • Cores can be distributed across as many virtual machines (VMs) as needed. For example, ten 2-core subscriptions will provide 20 cores and in case of IBM Power Systems a 2-core subscription at SMT level of 8 will provide 2 cores or 16 vCPUs that can be used across any number of VMs.
  • OpenShift Container Storage subscriptions are available with Premium or Standard support.

6.2. Disaster recovery subscriptions

Red Hat OpenShift Container Storage does not offer disaster recovery (DR), cold backup, or other subscription types. Any system with OpenShift Container Storage installed, powered-on or powered-off, running workload or not, requires an active subscription.

6.3. Cores versus vCPUs and hyperthreading

Making a determination about whether or not a particular system consumes one or more cores is currently dependent on whether or not that system has hyperthreading available. Hyperthreading is only a feature of Intel CPUs. Visit the Red Hat Customer Portal to determine whether a particular system supports hyperthreading.

For systems where hyperthreading is enabled and where one hyperthread equates to one visible system core, the calculation of cores is a ratio of 2 cores to 4 vCPUs. Therefore, a 2-core subscription covers 4 vCPUs in a hyperthreaded system. A large virtual machine (VM) might have 8 vCPUs, equating to 4 subscription cores. As subscriptions come in 2-core units, you will need two 2-core subscriptions to cover these 4 cores or 8 vCPUs.

Where hyperthreading is not enabled, and where each visible system core correlates directly to an underlying physical core, the calculation of cores is a ratio of 2 cores to 2 vCPUs.

6.3.1. Cores versus vCPUs and simultaneous multithreading (SMT) for IBM Power Systems

Making a determination about whether or not a particular system consumes one or more cores is currently dependent on the level of simultaneous multithreading configured (SMT). IBM Power systems provide simultaneous multithreading levels of 1, 2, 4 or 8.

For systems where SMT is configured the calculation of cores depends on the SMT level. Therefore, a 2-core subscription 2 vCPU on SMT level of 1, 4 vCPUs on SMT level of 2, 8 vCPUs on SMT level of 4 and 16 vCPUs on SMT level of 8. A large virtual machine (VM) might have 16 vCPUs, which at a SMT level 8 will be equivalent of 2 subscription cores. As subscriptions come in 2-core units, you will need 1 2-core subscription to cover these 2 cores or 16 vCPUs.

6.4. Splitting cores

Systems that require an odd number of cores need to consume a full 2-core subscription. For example, a system that is calculated to require only 1 core will end up consuming a full 2-core subscription once it is registered and subscribed.

When a single virtual machine (VM) with 2 vCPUs uses hyperthreading resulting in 1 calculated vCPU, a full 2-core subscription is required; a single 2-core subscription may not be split across two VMs with 2 vCPUs using hyperthreading. See section Cores versus vCPUs and hyperthreading for more information.

It is recommended that virtual instances be sized so that they require an even number of cores.

6.4.1. Shared Processor Pools for IBM Power Systems

IBM Power Systems have a notion of shared processor pools. The processors in a shared processor pool can be shared across the nodes in the cluster. The aggregate compute capacity required for a OpenShift Container Storage should be a multiple of core-pairs.

6.5. Subscription requirements

OpenShift Container Storage components can run on either OpenShift Container Platform worker or infrastructure nodes, for which either Red Hat CoreOS (RHCOS) or Red Hat Enterprise Linux (RHEL) 7 can be used as the host operating system. When worker nodes are used for OpenShift Container Storage components, those nodes are required to have subscriptions for both OpenShift Container Platform and OpenShift Container Storage. When infrastructure nodes are used, those nodes are only required to have OpenShift Container Storage subscriptions. Labels are used to indicate whether a node should be considered a worker or infrastructure node, see How to use dedicated worker nodes for Red Hat OpenShift Container Storage in the Managing and Allocating Storage Resources guide.