BLOG: Red Hat OpenShift on LinuxONE and IBM Z running under KVM

May 4th, 2021 BLOG: Red Hat OpenShift on LinuxONE and IBM Z running under KVM
Andy Hartman
Senior Consultant

 

With IBM and Red Hat’s push to help clients move and develop new applications built for hybrid cloud and take advantage of easily deployed open source and IBM Cloud Pak solutions , Red Hat has made significant enhancements to its OpenShift Container Platform (OCP). The enhancements allow enterprises to run their cloud native applications on a cloud provider such as IBM Cloud or on premises utilizing their own infrastructure such as IBM Z or LinuxONE. In February 2021, Red Hat released 4.7 of its OpenShift Container Platform. Along with many fixes, API enhancemets and new features, one of the bigger features pertaining to the IBM Z system hardware platform was the new ability to deploy OpenShift on IBM Z or LinuxONE running under KVM (Kernel Virtual Machine).

 

Virtualization

IBM Z and LinuxONE have two virtualization technologies:

1. z/VM – the native virtualization option and virtual machine technology that supports Linux and the IBM operating systems z/OS, z/VSE and z/TPF for traditional IBM Z workloads as well as newer workloads such as OpenShift.

z/VM is highly integrated with the hardware and firmware for IBM Z and LinuxONE and was the option available when OpenShift was released to run on the IBM Z and LinuxONE.

2. KVM – a common virtualization technology based on the Linux kernel which supports Linux virtualization on a Linux host running on many distinct types of hardware such as IBM Z and x86.

The ability to run OpenShift on KVM allows more administrators with existing KVM skills to deploy OpenShift clusters without the need to learn a new operating environment, cutting down on the time needed to deploy these clusters.

 

The setup and configuration of OpenShift is very much the same on either z/VM or KVM with the major differences being how the virtual machines that host the OpenShift cluster are deployed. In both instances, OpenShift deployed on IBM Z or LinuxONE is considered a User Provisioned Infrastructure which means the compute, network, and storage used by OpenShift to host the cluster needs to be provisioned or “setup”. To help automate this process you can utilize Ansible to automate the setup of various servuces needed by OCP on a bastion machine such as proxy , ftp and dns servers. Once the virtual machines are defined a bootstrap machine is started with an installer which provisions all the control plane and compute nodes on the other virtual machines.

The hardware and software requirements are the same between the two hypervisors with KVM requiring Red Hat Enterprise Server (RHEL) 8.3 to host the virtual machines that will be used to run the management (control plane) and compute (worker) nodes for the OpenShift Cluster. However, z/VM hosts the virtual machines directly and does not require a Linux server host to run the Linux guest machines.

The setup and installation are easy and straight forward with some excellent documentation from both Red Hat and IBM. RHEL 8.3 is included in the price of the OpenShift product so a separate license is not necessary when using RHEL to host an OpenShift cluster. When installing OpenShift on LinuxONE and IBM Z you can utilize the traditional installation method which requires access to the internet to download the various OpenShift components along with updates during and after the cluster is built. There is also a restricted option that allows you to install OpenShift and deploy a cluster without direct access to the internet. The latter option involves pre-staging the components needed on other servers in your internal network and then performing the installation and deployment from those servers.

 

Storage and Other Enhancements

OpenShift 4.7 is based around Kubernetes 1.20. It utilizes Red Hat Enterprise Linux CoreOS (RHCOS) which is based on Red Hat Enterprise Linux 8.3.
Other enhancements related to IBM Z and LinuxONE in this release of OpenShift center around various storage options.

  • Multipathing is now supported when utilizing Fiber Channel Protocol (FCP) attached storage providing high availability to SCSI disk devices.
  • z/VM emulated FBA devices are now supported when deploying your cluster under z/VM offering an additional way to exploit FCP SCSI disks.
  • iSCSI support is available for persistent storage increasing the available storage options to TCP/IP connected storage servers, beyond just FC or FCP.
  • HyperPAV is supported for Fiber Channel attached ECKD DASD providing greater utilization and performance.

There are now three different solutions available on IBM Z and LinuxONE for shared persistent storage:

1. NFS has been available for a while and is a satisfactory solution for small, nonproduction clusters allowing you to take advantage of existing or easily provisioned NFS servers in your network at no additional cost.

2. IBM Spectrum Scale with IBM Spectrum Scale Cloud Native Storage Access is an enterprise scale, production-ready solution that provides a highly scalable, highly available, cluster-based solution with Backup and Disaster Recovery capabilities and it is supported on both FCP and FC attached storage. This solution can share data between different architectures like IBM Power, x86 and IBM Z.

3. OpenShift Container Storage (OCS) is available as a Technology Preview for OCP 4.6 and 4.7. OCS is widely used with OpenShift on other platforms such as x86 and has been developed to run with the OCP. It is a software defined storage solution backed by SCSI storage. As a technical preview, OCS is not supported for production but should be fully supported in a future release.

 

Conclusion

With the ability to utilize KVM on IBM Z and LinuxONE , OpenShift 4.7 enables you to deploy your cloud native applications in the hypervisor environment which best suits your needs. Along with these OpenShift enhancements IBM has continued to add to their Cloud Paks which enables you to build diverse types of solutions around automation, artificial intelligence, data, security, and integration. With LinuxONE and IBM Z you can host your entire on-prem cloud solution giving you unmatched security, reliability, and scale.

 

Get More Information

As an IBM Platinum Business Partner, Mainline has extensive experience with IBM mainframe systems and operating systems, and we can help you with Red Hat OpenShift, IBM Cloud Paks, z/OS, z/VM, Linux on IBM Z, and LinuxONE. To set up an in-depth discussion about how to get started using these technologies, please contact your Mainline Account Executive directly or contact us with any questions.

 

Related Articles and Links

Kubernetes and Red Hat OpenShift on IBM Z and LinuxONE

Links to Running OpenShift on IBM Z and LinuxONE:

4.7 Release Notes

4.7 Installing a cluster on KVM on IBM Z and LinuxONE

4.7 Installing a cluster on z/VM on IBM Z and LinuxONE

Red Hat OpenShift Container Platform on IBM Z and LinuxONE – Reference Architecture

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