Red Hat customer, COFCO International, migrated to the latest Red Hat Enterprise Linux (RHEL) release. They upgraded their RHEL 7 systems hosting SAP workloads to RHEL 8. Without the hassle of creating new virtual machines and redeploying SAP applications, COFCO International saved resources, minimized downtime and enabled an upgrade path for the RHEL 9 release version. 

Note that the RHEL 7 maintenance support phase ends in less than a year (June 30, 2024). To support our customers in completing their planned migrations, Red Hat has announced a one-time, four-year Extended Life (ELS) phase maintenance period for RHEL 7 ELS. In this series, we'll share some of our customers' experiences and best practices of their migration to a newer major version of RHEL, taking advantage of new features and enhancements.

Migrating to the newest RHEL to maintain SAP certification

COFCO International is a global agriculture supply chain company in the food processing, production and trading business, with about 12,000 employees in 36 countries. COFCO International follows a cloud-first strategy and runs its workloads on Microsoft Azure. Azure is a cloud computing platform by Microsoft, a Red Hat partner and certified cloud service provider.

To host business-critical SAP workloads, such as SAP S/4 HANA, NetWeaver and others, COFCO International decided to adopt RHEL. According to Pedro Proenca Relvas, SAP Basis Engineer,  "The [main] reason that led us to pick RHEL was the market share it had which would, [in addition], benefit us in searching engineers for our teams in the future. Our team had the RHEL knowledge. [Another] reason RHEL was picked was due to the fact that it was first and foremost SAP certified and it had RHEL High Availability Add-on."

Nowadays, the COFCO International SAP landscape is powered by RHEL for SAP with HA and US and RHEL for SAP Applications solutions using pay-as-you-go (PAYG) and bring-your-own-subscription (BYOS) models. COFCO International also clusters its resources, thanks to the RHEL High Availability (HA) Add-On included in RHEL for SAP with HA and US subscription, which helps to keep critical SAP environments more resilient at the application and database levels, increases uptime, and reduces unplanned service disruptions.

To deploy, maintain, and support its landscapes, COFCO International uses Ansible: "With [...] Ansible, we are able to automate various repetitive tasks from the OS and HANA layer. So it gives the team more time to focus on the important topics," said Pedro. COFCO International uses Ansible for such operations as minor RHEL release updates, HANA DB user management, stop/start SAP applications and patching.

In 2022, COFCO International decided to upgrade SAP S/4 HANA to the SAP S/4 HANA 2021. One of the requirements for this upgrade was to run RHEL 8.

"Usually the operating system behind the SAP systems is upgraded when there are business requirements due to a HANA Database upgrade or a SAP stack upgrade to bring new features. Therefore an easy in-place upgrade with the Leapp tool is nowadays more important than ever," Pedro stated.

Saving resources

The option of creating new virtual machines (VMs) running RHEL 8 and installing, configuring and moving the SAP workloads was not appealing to COFCO International. "That would mean doubling the cost on virtual machines in addition to a great amount of work for our engineers to install and configure everything again. Installing HANA and restoring a database can take hours depending on its size. With Leapp, we save a lot of time," said Pedro. 

At first, COFCO International tested the upgrade procedures on standalone RHEL for SAP with HA and US and RHEL for SAP Application sandboxes running PAYG and BYOS models. Pedro said, "We had a huge success with it. All the [testing] environments that we have upgraded had all the SAP workloads running without issues." After successful testing, COFCO completed the upgrade of its non-production and production landscapes. 

Minimizing downtime using automation

The upgrade procedure can take several minutes to hours and requires downtime. Minimizing downtime for systems running critical SAP business applications is crucial for maintaining operational efficiency and seamless business operations. To minimize downtime, COFCO International thoroughly planned the upgrade process. "We wanted to reduce the downtime as much as possible," said Pedro.

The upgrade consists of pre-upgrade, upgrade and post-upgrade steps. The COFCO team completed the pre-upgrade steps a day before the upgrade. On the day of the upgrade, it only needed to stop the SAP workloads, proceed with the upgrade steps and then complete the post-upgrade steps. To avoid any business disruption during actual working hours, the COFCO team performed the upgrade on systems in the opposite timezone. To automate repetitive tasks, reduce human error and improve consistency, pre-upgrade and post-upgrade steps were performed with the help of Ansible.

For non-HA landscapes, standalone VM downtime is defined by the completion of Leapp upgrade (including reboot) procedures and SAP workload stop/start tasks. For HA environments, downtime can be reduced to just the failover time of critical resources, assuming all services are duplicated or clustered.

Pedro elaborated, "For SAP Application systems the upgrade usually took between 30-45 minutes. For standalone HANA DB SAP systems it took only up to 1 hour with 45 minutes downtime. When combining the upgrade with the Ansible automation for the pre-upgrade steps, we could reduce the upgrade process to 40-50 minutes. To complete the upgrade for clusters of four VMs it usually took 2-3 hours with 15 minutes downtime."

An upgrade of clusters takes longer than a standalone system. An upgrade of an active cluster running RHEL 7 to RHEL 8 is not possible due to major high availability differences. To upgrade a cluster, nodes need to be removed from the cluster, upgraded individually and a new cluster must be created. 

To limit downtime to 15-20 minutes, COFCO International kept one or two cluster nodes running HANA while upgrading other nodes and creating a new cluster. Next, the team moved the HANA workload to the cluster with upgraded nodes and upgraded the remaining nodes to add them to the new cluster. After upgrading the clusters, COFCO International also performed test failover procedures to validate their functionality.

Verifying functionality

COFCO International worked closely with Red Hat Support during the upgrade from RHEL 7 to RHEL 8 in a test environment. The generously shared feedback contributed to bug fixes, enhancements development and documentation improvements.

"The Leapp in-place upgrade is a very safe feature," Pedro said.

When thinking of upgrading an operating system, it is normal to consider possible disaster issues, especially when planning an upgrade of production systems. "We did not find any issue during the process of upgrading more than 300 virtual machines either standalone or clustered environments. We never once had any issue with SAP Applications or HANA databases starting up properly. Neither the server failed at the moment the upgrade ended, nor the upgrade hung during the reboot sequence. We never had to use any OS disk snapshots for recovery," said Pedro.

It only takes an engineer

"An upgrade of the RHEL major version is aimed more towards a Linux engineer or a SAP Basis team member who is used to working infrastructure. However, the way this tool is built, any member of a SAP Basis team can upgrade a standalone system without being afraid of breaking things," Pedro said. "It is quick to learn, easy to use and flexible for different workloads and target release versions."

Once the process works, upgrade everything

Because of the positive experience upgrading its SAP environment, COFCO upgraded other RHEL virtual machines, including backup agents and web servers. "If you can upgrade VMs with SAP, you can upgrade any other workloads. It only takes 15-25 minutes," noted Pedro.

Planning the future

Running the latest version of software is paramount for a business to be competitive and efficient. After upgrading from RHEL 7 to RHEL 8, the same work will help it move to the latest RHEL 9

"Here at COFCO, we are always looking for the next big step in our roadmap according to the business directions and needs. For the future we are looking into migrating our SAP landscape towards RHEL 9,” concluded Pedro.

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About the author

Irina Gulina joined Red Hat team in 2014 and nowadays is Senior Software Quality Engineer for Red Hat Enterprise Linux for SAP Solutions. Irina closely works with the Certified Cloud and Service Providers like Amazon Web Services (AWS), Microsoft, Google and others to ensure the quality of RHEL products on their marketplaces.

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