From 16b5f177cb1fa2f74166962ef2871f635bc4209d Mon Sep 17 00:00:00 2001
From: Nick Dunklee <ndunklee@sovrn.com>
Date: Mon, 30 Sep 2024 16:38:22 -0600
Subject: [PATCH] Updating cross-compile for both aarch64 and x86_64 on ARM

---
 sovrn/Dockerfile | 10 ++++++++--
 sovrn/README.md  |  9 +++++++++
 2 files changed, 17 insertions(+), 2 deletions(-)

diff --git a/sovrn/Dockerfile b/sovrn/Dockerfile
index f6e7ff0de50d..dc43d6416c06 100644
--- a/sovrn/Dockerfile
+++ b/sovrn/Dockerfile
@@ -11,8 +11,14 @@ RUN wget https://downloads.lightbend.com/scala/2.12.17/scala-2.12.17.tgz -P /tmp
     ln -s /usr/local/scala-2.12.17 /usr/local/scala && \
     rm /tmp/scala-2.12.17.tgz
 
-# Set environment variables for Java, Python, Maven, and Scala
-ENV JAVA_HOME=/usr/lib/jvm/java-1.8.0-amazon-corretto.aarch64
+# Set a default value for TARGET_PLATFORM
+# This is chosen at build time using the --build-arg flag
+# Example: docker build --build-arg TARGET_PLATFORM=aarch64 -t xgboost .
+ARG TARGET_PLATFORM=aarch64
+#ARG TARGET_PLATFORM=x86_64
+
+# Set environment variables for Java and Scala
+ENV JAVA_HOME=/usr/lib/jvm/java-1.8.0-amazon-corretto.${TARGET_PLATFORM}
 ENV PATH=${PATH}:${JAVA_HOME}/bin:/usr/local/scala/bin
 
 # Set Java 8 as the default Java version
diff --git a/sovrn/README.md b/sovrn/README.md
index aa4465c0e0d0..860e0b5f72f5 100644
--- a/sovrn/README.md
+++ b/sovrn/README.md
@@ -23,6 +23,15 @@ docker run -v $(pwd)/..:/xgboost --rm -it xgboost-build
 
 Now you should have a Docker ready to build your jar for aarch64/ARM64.
 
+## Cross-Compile XGBoost for x86_64 on ARM64
+
+```bash
+docker buildx create --name xgboost-builder --use
+docker buildx inspect --bootstrap
+docker buildx build --platform linux/amd64 -t xgboost-build . --load --build-arg TARGET_PLATFORM=amd64
+docker run -v $(pwd)/..:/xgboost --rm -it --platform linux/amd64 xgboost-build
+```
+
 # Inside the Docker
 
 ```bash