Faster startup for containerized applications with Liberty InstantOn

Liberty InstantOn improves startup times for containerized applications by creating an extra application image layer that contains a checkpoint of the application process. When the application image starts, the Liberty runtime restores the application process from that checkpoint.

For more information about building, running, and deploying InstantOn-enabled application images, see the Open Liberty website.

InstantOn-supported architectures and Java SE levels

InstantOn requires the Linux operating system with kernel version 5.9 or greater.

The following table defines the supported IBM Semeru Java levels and minimum Liberty version for each supported architecture. InstantOn is not supported on Java vendor implementations other than IBM Semeru.

Table 1. Supported Java levels and Liberty versions for InstantOn
Architecture Supported IBM Semeru Java levels Minimum Liberty version

Linux X86_64 UBI (amd64)

  • Java SE 11.0.19+
  • Java SE 17.0.7+
  • Java SE 21.0.1+
23.0.0.6 and later

Linux on Power (ppc64le)

Java SE 21.0.1+ 24.0.0.1 and later

Linux on IBM Z (s390x)

Java SE 21.0.1+ 24.0.0.1 and later

InstantOn-supported WebSphere Liberty features

InstantOn supports a subset of WebSphere® Liberty features. If a feature that InstantOn does not support is enabled in the server.xml file, a failure occurs during the checkpoint.

In addition to all the InstantOn-supported features that are listed on the Open Liberty website, InstantOn also supports the WebSphere Liberty-only System for Cross-domain Identity Management feature.