The CentOS Project announced the end of life (EOL) for CentOS Linux. If you are a CentOS Linux user, you may be concerned about how to update, maintain, and migrate your CentOS operating system (OS) after CentOS Linux reaches EOL. To address the concerns of a variety of users, Alibaba Cloud provides several plans for migrating away from CentOS Linux. This topic describes the plans and some success stories about using these plans.

Background information

On December 08, 2020, the CentOS Project announced that it would discontinue CentOS Linux. For more information, see CentOS Project shifts focus to CentOS Stream.

The CentOS Project is shifting focus from CentOS Linux, a rebuild of Red Hat Enterprise Linux (RHEL), to CentOS Stream. This shift affects current CentOS Linux versions in the following ways:
  • CentOS 7 continues to be supported and is scheduled to reach EOL on June 30, 2024.
  • CentOS 8 had its lifecycle cut short to December 31, 2021.

Impacts of CentOS Linux EOL

According to CentOS Project announcements and as known by Alibaba Cloud, the EOL of CentOS Linux has the following impacts:
  • If you are using CentOS 8, you no longer receive software maintenance or technical support such as bug fixes and feature updates after December 31, 2021.
  • If you are using CentOS 7, you will no longer receive software maintenance or technical support such as bug fixes and feature updates after June 30, 2024.

Migration plans

Alibaba Cloud provide comprehensive plans in collaboration with the Anolis community (OpenAnolis) for you to migrate from CentOS Linux to Anolis OS or Alibaba Cloud Linux, which include migration assessment, migration tools, and long-term support from Alibaba Cloud.

Compared with other open source migration plans, the migration plans provided by Alibaba Cloud have the following advantages: These migration plans comprise systemized solutions developed by Alibaba Cloud and are backed by support tool platforms and long-term support from Alibaba Cloud. Meanwhile, these migration plans are fully compatible with the CentOS ecosystem, have differentiated technical advantages, and have been verified in a wide array of scenarios and user success practices.

Plan details

The migration plan consists of migration assessment and implementation.

Migration assessment
In migration assessment, the migration assessment tool scans and retrieves the information of source CentOS Linux OSs and compares the information with that of destination Anolis OSs or Alibaba Cloud Linux OSs to identify migration risks. The migration assessment tool assesses OSs and services, as shown in the following figure.Migration assessment
  • Service migration assessment: The migration assessment tool recognizes the application types of services and works out migration solutions based on the application types.
  • OS migration assessment: The difference assessment tool finds out the differences in kernels, software packages, and system configurations between source OSs and destination OSs and uses these differences as the basis for migration.
Migration implementation
Migration can be implemented in new deployment or in-place migration mode. Take note of the following items:
  • New deployment

    In new deployment mode, a destination OS is installed and all applications and configurations are re-deployed. This mode is suitable for scenarios such as cluster scaling and node replacement.

  • In-place migration

    In in-place migration mode, a CentOS Linux OS is upgraded in place, and all applications, system configurations, and application configurations are retained without the need to re-deploy them or migrate data. This mode is suitable for services that are not affected by underlying OS changes, such as Java programs. Java Development Kit (JDK) adapts to the underlying OS. If the pre-migration and post-migration JDK versions are the same, services are not affected. For example, assume that a Hadoop multi-node cluster is set up based on java-1.8.0-openjdk on CentOS 8. In an in-place migration, after the cluster is migrated to Anolis OS 8, the configurations of the head node are retained, data storage on data nodes remains normal, and the cluster can work normally.

Migration guidelines

Alibaba Cloud provides specific migration guides for each CentOS Linux version:
Notice Before you use the migration tool to migrate away from CentOS Linux, note that migration procedures cannot be reserved and that software packages are automatically re-installed during the procedures. Before you migrate your Elastic Compute Service (ECS) instances away from CentOS Linux, you must create snapshots for the instances to back up data. For more information about snapshots, see Snapshot overview.
  • For information about how to migrate from CentOS 7 to Anolis OS 7, see Migrate from CentOS 7 to Anolis OS 7.
  • For information about how to migrate from CentOS 8 to Anolis OS 8, see Migrate from CentOS 8 to Anolis OS 8.
  • For information about how to migrate from CentOS 7 to Alibaba Cloud Linux 2, see Migrate from CentOS 7 to Alibaba Cloud Linux 2.
    Note Alibaba Cloud Linux 2 uses kernel version 4.19, which is incompatible with kernel version 3.10 of CentOS 7. Applications that must call the kernel API to program, such as to build out-of-tree kernel modules and to enable hardware, must be assessed beforehand to determine whether a direct migration is feasible and ensure that the applications can run normally after the migration.
  • For information about how to migrate from CentOS 8 to Alibaba Cloud Linux 3, see Migrate from CentOS 8 to Alibaba Cloud Linux 3.
    Note Alibaba Cloud Linux 3 uses kernel version 5.10, which is incompatible with kernel version 4.18 of CentOS 8. Applications that must call the kernel API to program, such as to build out-of-tree kernel modules and to enable hardware, must be assessed beforehand to determine whether a direct migration is feasible and ensure that the applications can run normally after the migration.

Success stories