8.2.2.2 Understanding Exadata Live Update

Exadata Live Update provides versatile online update capabilities for Exadata database servers.

Oracle Exadata System Software release 24.1.0 introduces Exadata Live Update, a suite of enhancements to the mechanisms that orchestrate Exadata software updates on Exadata database servers only.

Exadata Live Update includes the following key capabilities:

• Exadata Live Update uses online update capabilities based on standard Linux technologies, such as DNF and Ksplice. Depending on the specific contents of the update, the update operation might occur without interrupting databases or rebooting the server.

• Exadata Live Update supports partial updates to address security issues. When using Exadata Live Update, you must choose from the following options:

  • highcvss: Performs only critical security updates to address vulnerabilities with a Common Vulnerability Scoring System (CVSS) score of 7 or greater.

  • allcvss: Performs only security updates to address vulnerabilities with a CVSS score of 1 or greater.

  • full: Performs a full update, which includes all security-related updates and all other non-security updates.

• Exadata Live Update can be controlled using the Exadata patchmgr utility, which provides an easy and familiar experience for existing Exadata users.

Note the following usage details relating to Exadata Live Update:

• Exadata Live Update may only be used for specific updates that it supports. For details, always refer to the release information associated with each update.

• For supported updates, Exadata Live Update may be used on bare-metal Exadata database servers, KVM hosts, KVM guests, Xen hosts (Dom0), and Xen guests.

• Exadata Live Update does not support database server updates that include a major operating system update. For example, from Oracle Linux 8 to Oracle Linux 9.

• Exadata Live Update includes the concept of outstanding work. Outstanding work describes update items that cannot be completed online and are staged for completion during a later reboot, typically including additional RPM packages that must be installed at reboot.

  For example, an update might include a Ksplice patch that fixes an issue in the running kernel and a newer kernel RPM that includes the same fix. Exadata Live Update can apply the Ksplice update online, so the fix takes effect immediately. However, installing and activating the newer kernel RPM cannot be completed online and must be staged as outstanding work.

  By default, outstanding work is automatically scheduled to occur during the next graceful server reboot. However, you can choose to schedule completion at a specific time or leave the work unscheduled until you reschedule it. For example, if an installed Ksplice patch already addresses an issue, you might defer the reboot needed to install and start using a newer kernel version that includes that same fix.

  Note:

  After Exadata Live Update updates user-space packages, processes that were already running might continue using libraries loaded before the update. As a result:

  • dnf needs-restarting -r can report that a reboot is required to fully use the updates.

  • dnf needs-restarting -s can identify services to restart.

  The DNF commands indicate whether running processes need to be restarted to fully use installed updates. The system can continue operating without immediate action, but affected processes might continue using previously loaded libraries and remain exposed to issues addressed by the updates until they are restarted.

  These DNF reports are separate from Exadata Live Update and can occur even when Exadata Live Update reports no outstanding work.

  WARNING:

  When outstanding work is performed, the associated system reboot may take longer than usual. During that time, the system may appear unresponsive. In such cases, it is vital to allow the outstanding work to finish. Do not interrupt the system! Interrupting the Exadata Live Update apply service may damage the system.

• You can perform another update with Exadata Live Update before completing the outstanding work associated with any previous update. In such cases, all necessary outstanding work will still be performed. However, the outstanding work associated with the latest update takes precedence and replaces the outstanding work from the earlier update.

• If any item of outstanding work does not complete following the designated system reboot, it is automatically rescheduled for the next graceful server reboot.

• A reboot is required to undo (roll back) an update performed using Exadata Live Update. Consequently, automatic rollback never occurs when using Exadata Live Update.

• To facilitate flexible management of software packages, Exadata Live Update removes the exadata-sun*computenode* software packages (for example, exadata-sun-kvm-computenode-minimum).

  Consequently, Exadata Live Update cannot detect custom software packages and manage their dependencies, which may inadvertently cause issues with non-Oracle software packages. In general, Oracle recommends that users minimize installation of software packages apart from Oracle Exadata System Software. This recommendation is even more pertinent on systems using Exadata Live Update.

  If you later perform a conventional update (not using Exadata Live Update), that update will reinstall the exadata-sun*computenode* software packages.