CentOS stops maintenance, read the upgrade migration path in one article

Since its inception in 1994, Red Hat Linux has accompanied developers on a journey of nearly 30 years. In 2014, Red Hat absorbed the main members of the CentOS community, including the project leaders and core project contributors at that time. The Red Hat and CentOS projects have joined forces to develop the next generation of Linux innovations for enterprise IT. Over the years, we've seen the open source model continue to flourish, fueling the rise of Linux containers, Kubernetes, microservices, serverless, and more. Given the rapid pace of community-driven innovation, in 2019 the community leadership decided to introduce a new model to the CentOS Linux community: CentOS Stream, moving the community work upstream. CentOS Stream is a developer-oriented distribution designed to help community members, Red Hat partners, and others take advantage of open source innovation in a more stable and predictable Linux ecosystem.

The most impactful to end users is the phasing out of maintenance and updates for CentOS Linux 7 and 8. How should existing CentOS Linux operating system users cope? What strategies and practical experiences can you draw from? Facing the common problems of users and developers, Amazon Cloud Technology Tech Talk specially invited Zhu He, senior solution architect of Red Hat, to share relevant technologies with the theme of "Corresponding Solutions and Technical Practices after the CentOS Operating System Stops Maintenance".

Changes in the Linux ecosystem after CentOS is stopped

Many developers fail to sort out the relationship between the various versions in the Linux ecosystem. So let's start with a review. Since 2014, the Red Hat Enterprise Linux ecosystem has formed a situation where Fedora, RHEL, and CentOS Linux develop synergistically. The upstream community provides continuous innovation and technical architecture integration of the desktop operating system for the majority of development engineers through Fedora, and a version is released about every 6 months; the midstream is Red Hat Enterprise Linux, mainly for enterprises and application developers. Security and performance optimization, product iteration and development rhythm in an orderly manner; the downstream is the community-led CentOS Linux for cost-sensitive users and ecological developers. CentOS Linux version, the product iteration rhythm closely follows RHEL, users can enjoy the product advantages of Red Hat RHEL while obtaining it at zero cost.

Seven years later, the CentOS Linux community began to make adjustments in 2021, and gradually stopped the CentOS Linux 7 and 8 versions that were positioned downstream. The main work of the CentOS community will turn to RHEL upstream, and develop and maintain a new CentOS Linux version - CentOS Stream.

CentOS Stream is a Linux development platform from the CentOS project designed to increase transparency and collaboration around the Red Hat® Enterprise Linux® development process. CentOS Stream is open to anyone and free for everyone to use. It is primarily aimed at developers, partners and end users. These roles can obtain new features of RHEL in advance through CentOS Stream, and on this basis, they can do work such as developing third-party components to expand their influence on the RHEL ecosystem. The equivalent of CentOS Stream is RHEL's test field. During this process, the ecological positioning of Fedora and RHEL has not changed. Users can obtain installation media for CentOS Stream from the following address:

• https://centos.org/download

The CentOS community moves from downstream to upstream, and the release of CentOS Stream will also have some impact on downstream users who were originally using CentOS. The current changes of CentOS versions are as follows:

• CentOS Linux 6 was discontinued as early as November 2020;
• CentOS Linux 8 stops updating at the end of 2021;
• CentOS Stream 8 will end support on May 31, 2024, it is inherited from CentOS Linux 8;
• CentOS Linux 7 has more users, this version will stop supporting on June 30, 2024;
• CentOS Stream 9 will be released in the second quarter of 2021, and Red Hat is developing RHEL 9 products based on CentOS Stream 9;
• There will be no new versions of CentOS Linux in the future community, only CentOS Stream will continue to move forward.

Considering the above situation, Red Hat recommends the majority of CentOS Linux users to act in advance and choose a suitable path to start the migration work as soon as possible.

Key factors in migrating to a new operating system

During migration, different migration strategies should be adopted for different users. When enterprise users migrate to a new operating system, they will mainly consider cost factors, smooth transition and service support, and then split them into eight key factors to make decisions:

• Simple transitions with minimal business disruption
• Stable operation and solid IT foundation
• Production grade, stability, support and security
• Professional support for your IT team
• Huge partner ecosystem supports a variety of supplier choices
• The long-term value of lifecycle support and version flexibility
• A clear product roadmap you can trust
• Proactively analyze the environment to reduce enterprise risk

For CentOS users, several common conversion strategies include:

• Go offline directly after the end of the life cycle, and there are very few applicable scenarios.
• Move to other community free versions such as Rocky Linux, Ubuntu or the domestic community version. But this path is riskier, because these community versions are quite different from CentOS.
• Turn to domestic and foreign distributions such as SUSE, Amazon Linux 2.
• Move to a Red Hat-led community or distribution like CentOS Stream or RHEL.

If users just want to do some functional verification and compatibility verification work on the operating system environment, or prepare to develop their own community Linux version with CentOS as the baseline, emphasizing code contribution and fixing problems, then it is more suitable to turn to CentOS Stream. However, considering the very short life cycle of this version, the difficulty of meeting compliance requirements, the lack of security certification, the irregular update rhythm, and the lack of commercial support, Red Hat does not recommend running CentOS Stream in a production environment.

Based on the new upstream and downstream relationship of the Linux community after 2021, for desktop usage scenarios and operating system development needs, Red Hat recommends that users use Fedora as the baseline for testing and development versions, and create software components compatible with Red Hat's future Enterprise Linux on CentOS Stream Development work. Business-critical workloads in production environments are recommended to run on enterprise-grade Linux RHEL. In addition, a new direction is the container packaging and production process, which requires a base image as a base. To this end, Red Hat provides a unified basic image based on Linux RHEL, namely UBI, which is convenient for users to build and distribute unified and secure enterprise applications on top of the standard underlying container OS.

How different is it to experience a fully upgraded Linux on Amazon Cloud

Amazon Cloud Technology has been a Red Hat Certified Global Cloud Service Provider (CCSP) since 2008, and Red Hat RHEL operating system products can be used in various ways on Amazon Cloud Technology. The first method is called PAYG ("pay as you go"), you can directly select the corresponding instance subscription on Amazon Cloud Technology. The other method is called BYOS, that is, the user's own subscription to the cloud. This method is more suitable for customers who have purchased a Red Hat subscription to implement a hybrid cloud deployment strategy.

Amazon Cloud Technologies Red Hat RHEL products have three main lines:

• Standard Enterprise Linux subscription, which is the technical standard RHEL version.
• Proprietary version for SAP Hana.
• RHEL UBI product for containerized applications.

In addition, OpenShift products, Red Hat middleware, and containerized storage can be certified and tested on Amazon Cloud Technologies.

The combination of Red Hat RHEL and Amazon infrastructure environments provides performance benefits and build stability over traditional infrastructure environments. Users can use a flexible, stable and efficient operating environment in the cloud environment to build a future-oriented hybrid cloud infrastructure, freely choose which applications are deployed locally and which applications are deployed on the public cloud, and better combine the two .

The RHEL environment provided by Amazon Cloud Technologies is optimized to provide users with the best experience out of the box. Enterprise-grade Linux features are also brought to the public cloud, where computing workloads can be run. Amazon Cloud Technology's business analysis capabilities can also be combined with RHEL to help users better understand the health of the environment. In some more flexible usage scenarios, installing applications on the cloud can save money and costs while ensuring optimal application performance.

On Amazon Cloud, RHEL also provides high availability (HA), providing reliability, availability and scalability for critical production workloads. HA can solve the single point of failure problem and automatically switch the fault to the new node to ensure flexibility and uninterrupted service.

There are many benefits for users to run business-critical applications with Enterprise Linux on Amazon Cloud Technologies, which can be summarized as follows:

• Red Hat Enterprise Linux is maintained for up to ten years with a major release lifecycle that includes more advanced security features, patches, related guidance, and technical support efforts. Red Hat also provides some in-place upgrade tools to make migration smooth and easy.
• RHEL has a predictable, production-friendly release cadence, making it easy for users to plan their own version upgrade strategies and paths. At the same time, RHEL will provide complete documentation and support to help users better plan updates.
• RHEL brings many enterprise-grade built-in features for security and compliance, such as automation tools, regular proactive release and update notifications, push notifications, and a knowledge base for easy access to relevant issues and materials. In addition, a Red Hat subscription includes Red Hat Insights tools for management, automation, and predictive analytics.
• The Red Hat Convert2RHEL tool allows users to perform in-place upgrades on CentOS environments, simplifying the upgrade path.

For the majority of RHEL users, Red Hat RHEL on Amazon Cloud Technologies provides a comprehensive and very flexible subscription plan. Especially for individual developers and enterprise developers, Red Hat has prepared a 0-cost developer available subscription.

Move to Red Hat Enterprise Linux Migration Practice

If users choose to switch from CentOS to RHEL, Amazon Cloud Technology provides some tools to help users complete the task and ensure users enjoy the value of Red Hat subscription.

There are two main conversion paths:

• Public cloud prebuilt images. Customers choose RHEL when applying for nodes on the virtual instance of Amazon Cloud Technology, and the installed virtual environment uses the pre-built image of the public cloud. Amazon provides some pre-built images of CentOS in its cloud market, so users who use CentOS on the cloud can quickly switch to RHEL by simply selecting the corresponding RHEL image in the cloud market and deploying a new instance. Switching images requires redeploying related applications, backing up and exporting data, and there is some migration workload.
• For CentOS used in on-premises data centers, Red Hat provides some related migration services and tool support to help users migrate to RHEL through self-service and on-site implementation. If the user wants to deploy to Amazon Cloud Technology at the same time, Amazon Cloud Technology will provide some RHEL image application tools and methods for customizing the cloud to help users create an Amazon Cloud Technology application image of AMI, so that users can customize the image and upload it to the cloud, and at the same time meet the requirements of the cloud. The requirements for migrating RHEL-related applications to the cloud can kill two birds with one stone.
• Red Hat introduced Convert2RHEL standardized tool to simplify migration, it also supports migration from Oracle's Linux to RHEL. Convert2RHEL will automatically determine the conversion path according to the CentOS version, and replace the CentOS community package with the original Red Hat RHEL toolkit. After the conversion, the operating system will be restarted, completely replaced with the RHEL version and activated, completing the Red Hat RHEL subscription. For CentOS Linux 7 or Oracle Linux 7, the conversion target system is RHEL 7; for CentOS Linux 8 or Oracle Linux 8, the conversion target system is RHEL 8.

This switching scheme will bring many benefits:

• You can upgrade in place without redeploying the operating system or applications;
• The original environment configuration is preserved;
• Built-in failsafe and disaster recovery, support version rollback;
• The migration process is very short and the maintenance window is small;
• Activate your Red Hat Linux subscription immediately after conversion, simplifying steps;
• Use this procedure to get the latest RHEL version.

Zhu He demonstrated the process of quickly converting CentOS operating system to RHEL through Convert2RHEL.

Since the upper-layer application and the operating system depend on different degrees, when upgrading the system has a greater impact on the former, the user also needs a migration process. For example, some applications will be tested for compatibility with the new environment before migration, and applications may need to be split, aggregated, and other refactoring processes during the migration process. During the refactoring process, some application development work may be done, some modifications or optimizations may be done, or old hardware may be migrated to new hardware, and so on. The implementation of the migration process is used to deal with the various problems caused by operating system migration.

Red Hat will help users with project migration guidance or planning, providing a series of assistance and comprehensive management services. Red Hat will help users evaluate and sort out the data center operating environment infrastructure, help users examine application compatibility and the feasibility of migration solutions in terms of runtime, and provide corresponding consulting assistance in application development optimization.

For issues such as cross-platform, application recycling, and deployment design during the migration process, Red Hat can provide on-site operation and maintenance support to ensure a smooth transition for users until the migration is complete.

The Amazon cloud technology environment can also use Red Hat RHEL images in many ways, including cloud market AMIs, private AMIs, custom AMIs on the cloud, officially released Red Hat Gold images, and Amazon AMI versions provided by third-party partners, etc. channel obtained. The most direct way for domestic users is cloud market mirroring, built-in and built-in mirroring. If there is no applicable version or option available, RHEL users can still migrate RHEL to Amazon Cloud via a custom AMI image supported by Red Hat. Red Hat supports standard commercial subscription customers to deploy data center on-promise subscriptions directly to the Amazon cloud environment.

Summarize

To sum up, it can be seen that CentOS is derived from RHEL. Enterprises migrate to RHEL to obtain the greatest degree of security, stability, and reliability, as well as the greatest protection for existing assets. The subscriptions, products, and services provided by Red Hat, combined with the services and support provided by Amazon Cloud Technology during the CentOS conversion process, can help users solve various problems caused by CentOS suspension.