Author: Jerry (Gerald) Hosch, hosch@de.ibm.com
The new deployment options with the Red Hat® OpenShift® Container Platform 4.15 on IBM Z® and IBM® LinuxONE help to:
- lower the infrastructure prerequisites for Red Hat OpenShift deployments on IBM Z and IBM® LinuxONE,
- enable to benefit from the strengths of different architectures, and to
- reduce management efforts.
The new deployment options are: LPAR (logical partition), multi-architecture compute, single-node OpenShift, hosted control plane (tech preview), and new installation options are available as well.
Let’s start with the LPAR deployment. When using the LPAR deployment, the IBM Dynamic Partition Manager (DPM) mode provides high flexibility and great manageability. According to the desired setup, single-node OpenShift, 3 node cluster, or high availability cluster, one or at least 5 LPARs are required. The LPAR deployment has no impact on the applications, and the Red Hat OpenShift clusters can be scaled across multiple IBM Z / IBM® LinuxONE systems. Also, it is possible to create additional clusters for better availability. Using a LPAR deployment, no hypervisor is required, therefore an improved performance can be expected for most workloads. The other side, a LPAR installation does not provide the flexibility of a hypervisor-based installation regarding the placement of guests, memory, etc., and the tools to manage a dynamic guest creation. Note, if considering deploying Red Hat OpenShift on the Processor Resource/Systems Manager™ (PR/SM) mode, contact your IBM representative to get informed about the restrictions with that mode.
With 'multi-architecture compute', an exciting feature for deploying containerized applications across multiple architectures in one Red Hat OpenShift cluster is available. A Red Hat OpenShift cluster, control nodes and compute nodes, can be deployed on IBM Z / IBM® LinuxONE, and additional compute nodes can be run on different infrastructure architectures. This allows clients to elevate existing Red Hat OpenShift capabilities to build optimized composite solutions for their applications.
Picture shows a sample configuration: the Red Hat OpenShift cluster is installed with 3 control nodes and 2 compute nodes on IBM Z and IBM® LinuxONE and the compute nodes 3 and 4 are added on x86
For the specific benefits of IBM Z / IBM® LinuxONE with this feature, read the IBM Whitepaper (PDF): Empower the strengths of different infrastructure architectures.
Also possible, having a full function Red Hat OpenShift cluster on x86 and adding additional compute nodes running on IBM Z / IBM® LinuxONE – this function became available with Red Hat OpenShift 4.14.
With single-node OpenShift, available since Red Hat OpenShift 4.14, the prerequisites for a Red Hat OpenShift deployment on IBM Z / IBM® LinuxONE can be reduced to a minimum. Single-node OpenShift is a configuration of a standard OpenShift cluster that consists of a single control node, reducing the resource requirement to only 1/3. Single-node OpenShift offers both, control and compute node, capabilities in a single cluster, and allows users to add additional compute nodes to the cluster. A use case example is to run ‘IBM Z Security and Compliance Center’ in a single-node OpenShift environment in 'IBM zCX Foundation for Red Hat OpenShift'. Note: single-node OpenShift lacks cluster high availability – due to having only a single control node, so it may not be suitable for mission-critical workloads. If having single-node OpenShift extended with further separated compute nodes, availability of workload is improved, but still the cluster availability impacted due to the single control node.
‘Hosted control planes’ for Red Hat OpenShift help pave the way for a hybrid cloud approach and more. The hosted control planes feature enables the provisioning of control planes as pods on a hosting service cluster without requiring dedicated physical or virtual machines for each control plane, in contrast to the cluster deployment with stand-alone control planes. It decouples the control nodes from the compute nodes and uses the hosting cluster to deploy the control nodes like any other workload. In addition, it enables you to run many control planes on fewer nodes, and to get them started quickly – because they are pods. As well, multicluster management is more centralized and simplifies the cluster installation. Note: compute nodes within a Red Hat OpenShift cluster remain homogeneous, meaning that ‘hosted control planes’ do not enable heterogeneous compute nodes.
The quick deployment of Red Hat OpenShift clusters on IBM Z / IBM® LinuxONE is supported with the Assisted Installer and the Agent-based Installer. Both provide a user-friendly installation solution, without the need for a bootstrap node, and both supports single-node OpenShift, 3-node clusters, and highly availability topologies on IBM Z / IBM® LinuxONE. The Assisted Installer offers a solution offered on the Red Hat Hybrid Cloud Console and performs the cluster installation via the Web user interface without creating installation configuration files manually. This is done either by providing PXE artifacts for easy cluster installations on z/VM / Red Hat KVM, or a bootable ISO image is generated to be installed on Red Hat KVM, containing all information required to deploy a cluster. The REST API allows the automation of this task. The Agent-based Installer provides flexibility of user-provided infrastructure (UPI) installs with the ease of use of the Assisted Installer in disconnected environments. Today, it provides the PXE artifacts for easy cluster installations on z/VM and Red Hat KVM environments.
Multi-architecture compute, single-node OpenShift, hosted control plane (tech preview), and new the installation capabilities are supported on IBM Z / IBM® LinuxONE with the Red Hat OpenShift environments: Red Hat KVM, and IBM z/VM, and with ‘IBM zCX Foundation for Red Hat OpenShift’ are the ‘multi-architecture compute’ and single-node OpenShift options supported.
Learn more and read the Red Hat blog: Unveil Red Hat OpenShift 4.15
Release notes: Red Hat OpenShift 4.15 on IBM Z and IBM® LinuxONE