Chapter 1 Welcome to Oracle Linux 9

Oracle Linux 9 contains new features and enhancements that improve performance in different areas including automation and management, security and compliance, container management, and developer tools. These enhancements are especially designed to make the operating system adaptable to different types of deployment from strictly on-premises installations, hybrid deployments that combine on-premises and cloud installations, and full cloud deployment.

Important

Upgrading to the official Oracle Linux 9 release from the Oracle Linux 9 Developer Preview version is not supported. You must reinstall Oracle Linux 9 if you are currently running the Developer Preview version.

1.1 System Requirements and Limitations

To determine whether your hardware is supported on the current Oracle Linux 9 release, check the Hardware Certification List at https://linux.oracle.com/hardware-certifications. Note that hardware is added to the list as it becomes available and validated on Oracle Linux.

1.2 Available Architectures

The release is available for installation on the following platforms:

  • Intel 64-bit (x86_64) (x86-64-v2)

  • AMD 64-bit (x86_64) (x86-64-v2)

  • 64-bit Arm (aarch64) (Arm v8.0-A)

    The aarch64 platform is supported with Unbreakable Enterprise Kernel (UEK), which currently is the only kernel that is supported on this platform.

1.3 Shipped Kernels

Oracle Linux 9 on the x86_64 platform ships with the following default kernel packages:

  • kernel-5.14.0-70.13.1.el9_0 (Red Hat Compatible Kernel (RHCK))

  • kernel-uek-5.15.0-0.30.19.el9uek (Unbreakable Enterprise Kernel Release 7 (UEK R7))

    For new installations, the UEK kernel is automatically enabled and installed. It also becomes the default kernel on first boot.

    For the 64-bit Arm (aarch64) platform, Oracle Linux ships only with the UEK kernel. For more information that is specific to this platform, see Chapter 5, Release-Specific Information for Oracle Linux 9 (aarch64).

The Oracle Linux release is tested as a bundle, as shipped on the installation media image. When installed from the installation media image, the kernel's version included in the image is the minimum version that is supported. Downgrading kernel packages is not supported, unless recommended by Oracle Support.

Oracle Linux maintains user space compatibility with Red Hat Enterprise Linux (RHEL), which is independent of the kernel version that underlies the operating system. Existing applications in user space continue to run unmodified on Unbreakable Enterprise Kernel. No recertifications are required for RHEL certified applications.

About the Unbreakable Enterprise Kernel

The Unbreakable Enterprise Kernel (UEK) is a Linux kernel built by Oracle and supported through Oracle Linux support. UEK is tested on Arm (aarch64), Intel x86, and AMD x86 (x86_64) platforms. Each release contains additional features, bug fixes, and updated drivers to provide support for key functional requirements, improve performance, and optimize the kernel for use on Oracle products such as Oracle's Engineered Systems, Oracle Cloud Infrastructure, and large enterprise deployments for Oracle customers.

Typically, a UEK release contains changes to the kernel ABI relative to a previous UEK release. These changes require recompilation of third-party kernel modules on the system. To minimize impact on interoperability during releases, the Oracle Linux team works closely with third-party vendors regarding hardware and software that have dependencies on kernel modules. Thus, before installing the latest UEK release, verify its support status with your application vendor.

The kernel ABI for a UEK release remains unchanged in all subsequent updates to the initial release.

For more information about UEK such as tutorials, notices, and release notes of different UEK versions, go to https://docs.oracle.com/en/operating-systems/uek/.

1.4 Obtaining Installation Images

The following installation images for Oracle Linux 9 are available:

  • Full ISO of Oracle Linux for typical on-premise installations

  • Boot ISO of Oracle Linux for network installations

  • Boot ISO of the supported UEK release for installing on hardware that is supported only on UEK

  • Source DVDs

For additional information about Oracle Linux ISOs for aarch64 platforms, see Chapter 5, Release-Specific Information for Oracle Linux 9 (aarch64).

You can download these images from the following locations. Note that the images in these locations are for both the x86_64 and aarch64 platforms, unless indicated otherwise:

To prepare a downloaded image for installing Oracle Linux, see Oracle® Linux 9: Installing Oracle Linux.

Note

Aside from installation ISOs, you can also use Oracle Linux images to create compute instances on Oracle Cloud Infrastructure. For information about these images, see the release notes for the specific image that you are using on the Oracle Cloud Infrastructure Documentation page.

To use Oracle Linux on Oracle Cloud Infrastructure, see https://docs.oracle.com/iaas/oracle-linux/home.htm.

For information about the available ISOs for the three most recent updates to the Oracle Linux releases, refer to https://yum.oracle.com/oracle-linux-isos.html.

1.5 Upgrading From Previous Oracle Linux Releases

You can upgrade an Oracle Linux 8 system to the Oracle Linux 9 release by using the leapp utility.

For step-by-step instructions, as well as information about any known issues that you might encounter when upgrading your system, see Oracle® Linux 9: Performing System Upgrades With Leapp.