microsoft-openjdk

README

gcr.io/paketo-buildpacks/microsoft-openjdk

The Paketo Microsoft OpenJDK Buildpack is a Cloud Native Buildpack that provides the Microsoft OpenJDK implementations of JREs and JDKs.

This buildpack is designed to work in collaboration with other buildpacks which request contributions of JREs and JDKs.

Behavior

This buildpack will participate if any of the following conditions are met

• Another buildpack requires jdk
• Another buildpack requires jre

The buildpack will do the following if a JDK is requested:

• Contributes a JDK to a layer marked build and cache with all commands on $PATH
• Contributes $JAVA_HOME configured to the build layer
• Contributes $JDK_HOME configure to the build layer

The buildpack will do the following if a JRE is requested:

• Contributes a JRE to a layer with all commands on $PATH
• Contributes $JAVA_HOME configured to the layer
• Contributes -XX:ActiveProcessorCount to the layer
• Contributes $MALLOC_ARENA_MAX to the layer
• Disables JVM DNS caching if link-local DNS is available
• If metadata.build = true
  • Marks layer as build and cache
• If metadata.launch = true
  • Marks layer as launch
• Contributes jvmkill to a layer marked launch
• Contributes Memory Calculator to a layer marked launch

Configuration

Environment Variable	Description
$BP_JVM_VERSION	Configure the JVM version (e.g. 11, 16). The buildpack will download JDK and JRE assets that are compatible with this version of the JVM specification. Since the buildpack only ships a single version of each supported line, updates to the buildpack can change the exact version of the JDK or JRE. In order to hold the JDK and JRE versions stable, the buildpack version itself must be stable. Buildpack releases (and the dependency versions for each release) can be found here. Few users will use this buildpack directly, instead consuming a language buildpack like paketo-buildpacks/java who's releases (and the individual buildpack versions and dependency versions for each release) can be found here. Finally, some users will will consume builders like paketobuildpacks/builder:base who's releases can be found here. To determine the individual buildpack versions and dependency versions for each builder release use the pack inspect-builder <image> functionality.
$BP_JVM_TYPE	Configure the JVM type that is provided at runtime, i.e. a JDK or JRE - accepts values "JDK" or "JRE" (default). If a JRE type is requested but not available, a JDK will be provided.
$BPL_JVM_HEAD_ROOM	Configure the percentage of headroom the memory calculator will allocated. Defaults to 0.
$BPL_JVM_LOADED_CLASS_COUNT	Configure the number of classes that will be loaded at runtime. Defaults to 35% of the number of classes.
$BPL_JVM_THREAD_COUNT	Configure the number of user threads at runtime. Defaults to 250.
$JAVA_TOOL_OPTIONS	Configure the JVM launch flags

Bindings

The buildpack optionally accepts the following bindings:

Type: dependency-mapping

Key	Value	Description
<dependency-digest>	<uri>	If needed, the buildpack will fetch the dependency with digest <dependency-digest> from <uri>

License

This buildpack is released under version 2.0 of the Apache License.