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What's new in the Red Hat UBI OpenJDK containers

July 19, 2023
Containers Java Kubernetes
Jonathan Dowland
OpenJDK

On June 6, we shipped the latest feature update to the OpenJDK containers with a number of new features:

  • All the containers are rebased onto the latest Red Hat Enterprise Linux (RHEL) point releases: RHEL 8.8 and RHEL 9.2.

  • We’ve improved the handling of the JAVA_APP_NAME configuration option to accept app names containing spaces (OPENJDK-1551).

  • We've updated the included version of Apache Maven from 3.6 to 3.8 (OPENJDK-1464).

  • We shipped the first source containers for the legacy RHEL 7-based OpenJDK containers. For more information on source containers, see this Red Hat Customer Portal article.

This release also includes the most recent Critical Patch Update (CPU) versions of OpenJDK 8, 11, and 17 (8u372, 11.0.19, and 17.0.7, respectively), which we independently shipped in April.

Maximum heap size

Last time we blogged about plans to change the default value for the configuration option JAVA_MAX_MEM_RATIO in the June update of the Universal Base Image (UBI) 8 images.

This option corresponds to the JVM argument -XX:MaxRAMPercentage, and we planned to change the default from 50.0 to 80.0 (80% of detected RAM) (OPENJDK-559), aligning the default with the UBI9 images.

Unfortunately, this change didn't make the cut for the June update, and the default value remains 50%. We are now targeting the August update for this change.

Customers who want to preview the new value can set it explicitly: JAVA_MAX_MEM_RATIO=80.0.

What's next

The next OpenJDK CPU is scheduled for July 18, 2023. We'll ship updated containers shortly afterward. As usual, those container updates will be solely for the updated OpenJDK and will not contain changes to the container scripts themselves. Our next container feature update is planned for August.

We do all our planning in the open on the Red Hat Issue Tracker. If there's something you'd like to see, get in touch, either by leaving a comment or (for an image change) filing an issue.

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