Self-managed OpenShift (Red Hat OpenShift Platform Plus, Red Hat OpenShift Container Platform, and Red Hat OpenShift Kubernetes Engine) can be used anywhere 64-bit Red Hat Enterprise Linux is certified and supported.
Red Hat OpenShift 4 supports three primary deployment methods:
- Platform-specific installer-provisioned infrastructure (IPI). PProvides full integration, with underlying infrastructure platforms (listed later in this section), to automate the cluster provisioning and installation process. The installer provisions all resources necessary for cluster installation and configures integration between the OpenShift cluster and the infrastructure provider. OpenShift clusters deployed using the installer provisioned infrastructure (IPI) method via the CLI or Red Hat Advanced Cluster Manager have full platform integration for supported infrastructure types.
- Platform-specific user-provisioned infrastructure (UPI). Depending on the infrastructure platform, a varying amount of integration between OpenShift and the underlying platform is available. The administrator provisions the resources necessary for cluster installation. Depending on the platform, the installer may configure infrastructure integration or the administrator may add integration post-deployment. OpenShift clusters deployed using the user provisioned infrastructure (UPI) method via the command-line interface (CLI) or Assisted Installer for OpenShift have this level of integration. User provisioned infrastructure clusters are deployed using the CLI or Assisted Installer for OpenShift, with specific infrastructure platform integration levels available during and after deployment varying based on the provider type.
- Platform-agnostic UPI or nonintegrated clusters. This deployment type provides no integration with the underlying infrastructure. This install method offers the broadest range of compatibility, but the administrator is responsible for creating and managing cluster infrastructure resources. Nonintegrated clusters are deployed using the CLI or Assisted Installer for OpenShift to any hardware or hypervisor certified for Red Hat Enterprise Linux.
For self-managed deployments, OpenShift can be installed on:
- Bare-metal servers.
- Virtualized environments, including:
- VMware vSphere.
- Red Hat Virtualization.
- Other certified virtualization platforms. Other platforms are supported via the platform-agnostic UPI install method.
- Private cloud environments.
- Red Hat OpenStack® Platform and Azure Stack Hub.
- Public cloud environments, including:
- Amazon Web Services, Azure, Google Cloud Platform, IBM Cloud, Alibaba Cloud, and VMware Cloud on AWS.
- Other certified public cloud platforms. Other platforms are supported via the platform-agnostic UPI install method.
For more information about which platforms are supported, visit the official OpenShift Container Platform documentation page.
Registration for Red Hat Cloud Access is required to use your OpenShift subscriptions on certified public cloud environments. For more information, visit the Red Hat Cloud Access page
Find out more about platforms and cloud environments on which Red Hat OpenShift has been tested and certified.
Red Hat OpenShift Platform Plus, Red Hat OpenShift Container Platform, and Red Hat OpenShift Kubernetes Engine subscriptions are available in two options, each with two support levels:
- Core-based (2 Cores or 4 vCPUs). This is based on the aggregate number of physical cores or virtual cores (vCPUs) across all the OpenShift worker nodes running across all OpenShift clusters. Available with Standard 8x5 or Premium 24x7 support SLA.
- Bare-metal socket pair (1-2 sockets with up to 64 cores). This subscription is available only for x86 bare-metal physical nodes where OpenShift is installed directly to the hardware, with the exception of IBM zSystem and Power architectures, which must use core-based subscriptions.
As with Red Hat Enterprise Linux:
- OpenShift subscriptions (Red Hat OpenShift Platform Plus, Red Hat OpenShift Container Platform, and Red Hat OpenShift Kubernetes Engine) are stackable to cover larger hosts.
- Core-based subscriptions can be distributed to cover all OpenShift worker nodes across all OpenShift clusters. For example, 100 2-core Red Hat OpenShift Platform Plus subscriptions will provide 200 cores (400 vCPUs) that can be used across any number of worker nodes, across all running OpenShift clusters.
Red Hat defines three types of disaster recovery (DR) environments—hot, warm, and cold. Paid OpenShift subscriptions are needed for hot DR only.
- Hot DR systems are defined as fully functional and running concurrently with the production systems. They are ready to immediately receive traffic and take over in the event of a disaster within the primary environment.
- Warm DR systems are defined as already prepared to deploy and host containerized workload representing a reasonable facsimile of that found in the primary site, but containing no customer workload from the source cluster(s).
- Cold DR systems are defined as having the infrastructure in place, but not the full technology (hardware, software, data) needed to restore service.
Hibernating clusters that are not expressly configured and designed for warm or cold DR—such as clusters running on cloud services that are temporarily hibernating owing to lower demand—require subscriptions. When warm or cold DR clusters are brought out of hibernation for running workloads, subscriptions are required. Bringing a cluster out of hibernation temporarily for routine maintenance or tests does not require an additional subscription for any of the components in OpenShift software offerings.
For both warm DR and cold DR, Red Hat OpenShift subscriptions can be transferred from the primary environment to the DR environment when the disaster occurs to restore service and maintain compliance with Red Hat’s subscription terms.
Migration and swing upgrades
Red Hat OpenShift 4 provides in-place upgrades between minor versions. If you are upgrading from Red Hat OpenShift 3, or need to perform a swing upgrade between OpenShift 4 minor versions as a result of maintenance windows or other considerations, your Red Hat OpenShift subscription will cover both the original and destination infrastructure of a one-way migration until such migration is complete. During the migration, Red Hat’s subscription management tools will show your environment as being out-of-compliance on the basis of the number of OpenShift subscriptions you purchased. Red Hat allows this for major version upgrades and will not require the purchase of additional subscriptions to get back into compliance during the migration. Finally, OpenShift provides tooling to assist in these migrations, along with Red Hat consulting services, if desired. See documentation on the migration toolkit for containers.
Entitlements for cores with hyperthreading
Making a determination about whether or not a particular OpenShift node uses one or more physical cores is determined by whether or not that system has hyperthreading enabled. Note that hyperthreading is only a feature of Intel central processing units (CPUs). Discover how to determine whether a particular system supports hyperthreading.
For systems where hyperthreading is enabled, and where one hyperthread equates to one schedulable system core, a calculation of cores at a ratio of 2 cores = 4 logical CPUs or vCPUs is used.
In other words, a two-core subscription covers four logical CPUs in a hyperthreaded system. For example, a virtual machine with eight vCPUs assigned will require four 2-core subscriptions when hosted in a virtual environment without hyperthreading, or two 2-core subscriptions when hosted in a virtual environment with hyperthreading enabled.
Red Hat OpenShift subscriptions use a system of measure called core bands. This means subscriptions (entitlements to deploy and use OpenShift) are applied and consumed at the OpenShift cluster level and apply to all eligible OpenShift compute nodes on that cluster. If you have multiple OpenShift clusters, you would aggregate the sum of cores consumed by the OpenShift compute nodes across all clusters to determine how many subscriptions are needed. For example, if you have 100 two-core Red Hat OpenShift Container Platform subscriptions, a total of 200 cores (400 vCPUs with hyperthreading) are available to be applied to the OpenShift compute nodes across all running OpenShift clusters.
Bare metal server considerations
A physical server can be entitled using either core-based (two-core/four logical CPU) or socket-based (1-2 socket, 64 cores) OpenShift subscriptions. If core-based subscriptions are used, stack a sufficient number of them to cover the total number of physical cores in the server.
In addition to core-based subscriptions, Red Hat also offers OpenShift socket-based subscriptions. For certain deployment types, this is a more economical option. The socket-based subscriptions are limited to entitling an x86 server with up to 2 sockets with a total of 64 cores across them. The socket-based subscriptions are currently available for x86 and ARM servers only and not for the IBM zSystem or Power architectures.
To entitle a physical server, stack one or more subscriptions to cover either the total number of sockets or physical cores in it (whichever is greater). For example, a server has two sockets and 48 cores. One subscription is needed because the server has two sockets and less than 64 cores, while a server with two sockets and 96 cores would need two subscriptions. Two subscriptions are needed to cover 96 cores because a single subscription covers a maximum of 64 cores.
Bare-metal socket-pair subscriptions also come with infrastructure subscriptions for the control plane and infrastructure. Qualified control plane and infrastructure workloads (explained in detail below) may be deployed to either, or a mix of, virtual and/or physical servers when using socket-based subscriptions. A mixed cluster, composed of virtual and physical nodes, is a supported deployment architecture when deploying a platform agnostic, non-integrated cluster without cloud provider or Machine API integrations.
Each physical, bare-metal server using socket-based entitlements can only be used as a single OpenShift node. Using a hypervisor, including OpenShift Virtualization, to create virtual OpenShift compute nodes will require entitling the virtual compute nodes using core-based subscriptions. This means that the bare-metal socket-pair model is best suited for resource intensive workloads like OpenShift Virtualization (where each workload is running a full virtual machine) or artificial intelligence and machine learning (AI/ML) (where each workload consumes a large amount of CPU and graphics processing unit (GPU).
Finally, using the bare-metal socket-pair subscriptions does not change the limitation of the number of containers per node (currently 250-500).
Alternative architectures (ARM, IBM zSystem, Power)
Red Hat OpenShift Container Platform can also run on ARM, IBM zSystem, IBM LinuxONE systems, and IBM Power Systems for customers using these platforms as the standard for building and deploying cloud-native applications and microservices. Only the core-based subscription model is supported for IBM zSystem and IBM Power platforms. ARM clusters are entitled using the same rules as x86.
For IBM zSystem customers, Red Hat OpenShift does not require the entire physical node to be entitled, only the cores used by OpenShift. IBM zSystem customers know this as “subcapacity” entitlement. Customers using only a subset of the available cores (compute capacity) on their IBM zSystem environment for OpenShift Container Platform only require subscriptions for the subset that is used for the compute nodes. This applies regardless of how CPU partitioning is achieved, whether by CPU pooling, capping, separate logical partitions (LPARs), or other means.
For IBM zSystem systems, one Integrated Facility for Linux (IFL) requires one OpenShift core-based subscription. When no partitioning is used, up to three IFLs may be identified for control plane or infrastructure services running on the host. These must be actively used for control plane and/or infra services to qualify and do not require OpenShift entitlements. Three-node compact cluster deployments require all IFLs to be entitled.
Red Hat OpenShift Platform Plus components beyond OpenShift Container Platform are not supported on IBM zSystem and IBM LinuxONE systems or IBM Power Systems at this time, with the following exceptions:
- A standalone subscription of Red Hat Quay running on x86 architectures provides a global registry for multiple architectures, including IBM zSystem and IBM Power clusters. Red Hat Quay itself will not run on IBM zSystem or Power.
- Red Hat Advanced Cluster Management for Kubernetes can be installed on IBM zSystem or IBM Power environments and manage Red Hat OpenShift nodes running on IBM zSystem or IBM Power environments.
- Red Hat OpenShift Data Foundation fully supports installation on IBM zSystem or IBM Power..
Red Hat OpenShift Kubernetes Engine is not supported on IBM zSystem and IBM LinuxONE systems, nor on IBM Power Systems.
Microsoft Windows Server containers support
Self-managed Red Hat OpenShift supports a subset of installation infrastructures and OpenShift features using Microsoft Windows Server containers. Windows Server containers are only supported on Microsoft Windows Server-based compute nodes. The control and infrastructure planes of the OpenShift environment must be running on x86 infrastructure using Red Hat Enterprise Linux or Red Hat Enterprise Linux CoreOS. For this reason, Windows Server container support is sold as a standalone subscription priced by core.
Red Hat OpenShift Platform Plus and Red Hat OpenShift Container Platform infrastructure can be used to deploy and manage Windows Server compute nodes. Microsoft Windows Server container support for Red Hat OpenShift subscriptions must be purchased as a separate add-on.
Red Hat Advanced Cluster Management for Kubernetes and Red Hat Advanced Cluster Security for Kubernetes do not support managing Microsoft Windows nodes, but Red Hat Quay running on x86 architectures can manage container images for Microsoft Windows Server-based workloads.
Red Hat OpenShift Platform Plus component support
The components of the Red Hat OpenShift Platform Plus subscription have different levels of support for alternative (non-x86) architectures and for Windows. Table 1 provides an overview of that support.