Support multiarch builds to run on other architectures e.g. Raspberry Pi

Dockerfile

@@ -39,7 +39,7 @@ RUN apt-get update && \
     printf "Build of nimmis/spigot:latest, date: %s\n"  `date -u +"%Y-%m-%dT%H:%M:%SZ"` > /etc/BUILDS/spigot && \
 
     # install application
-    apt-get install -y wget git jq && \
+    apt-get install -y wget git jq libatomic1 && \
 
     # Make special user for minecraft to run in
     /usr/sbin/useradd -s /bin/bash -d /minecraft -m minecraft && \
@@ -57,20 +57,13 @@ RUN apt-get update && \
 
     # get pgp key
 
-    # create java directory
-    mkdir -p /usr/lib/jvm/ && \
-
-    # download jdk and unpack in /usr/lib/jvm
-    curl -L https://github.com/adoptium/temurin${JAVA_VERSION_MAJOR}-binaries/releases/download/jdk-${JAVA_VERSION_MAJOR}.${JAVA_VERSION_MINOR}%2B${JAVA_VERSION_UPDATE}/OpenJDK${JAVA_VERSION_MAJOR}U-jdk_x64_linux_${JAVA_OPT}_${JAVA_VERSION_MAJOR}.${JAVA_VERSION_MINOR}_${JAVA_VERSION_UPDATE}.tar.gz | tar xz -C /usr/lib/jvm/ && \
-
-    # set compatible home path
-    ln -s /usr/lib/jvm/jdk-${JAVA_VERSION_MAJOR}.${JAVA_VERSION_MINOR}+${JAVA_VERSION_UPDATE} /usr/lib/jvm/default-jvm && \
-    ln -s /usr/lib/jvm/default-jvm/bin/java /usr/bin/java && \
-
-
     # remove apt cache from image
     apt-get clean all
 
+RUN mkdir -p /usr/lib/jvm/ && \
+
+    ln -s /usr/lib/jvm/default-jvm/bin/java /usr/bin/java
+
 # expose minecraft port
 EXPOSE 25565
 

README.md

@@ -328,6 +328,21 @@ and you should get an output simular to
 
 and the versionlist is updated.
 
+## Building the Docker Image
+To build this image for your machine you can simply use the normal docker build command
+
+	docker build -t spigot ./
+
+If you want to build this image for multiple architectures you need to use a slightly different set of commands. However this allows you to push a single image from which clients can automatically select the correct architecture.
+
+First set up a binfmt container which allows other architectures to be emulated
+
+	docker run --privileged --rm tonistiigi/binfmt --install all
+
+Then build the images and push (docker doesn't currently support loading multi-arch images directly)
+
+	docker buildx build --platform linux/amd64,linux/arm/v7,linux/arm64 --tag scratchcat1/minecraft-spigot:latest --push ./
+
 ## Old versions news
 
 - Updated java version to 17 which is a LTS version

rootfs/usr/local/bin/set_java_ver

@@ -6,10 +6,30 @@
 # (c) 2021 nimmis <[email protected]>
 #
 ###########################################################
+
+function get_cpu_arch_for_java () {
+  cpu_arch_line=$(lscpu | grep Architecture)
+  case "$cpu_arch_line" in
+    *x86_64*)
+      echo "x64"
+      ;;
+    *armv7*)
+      echo "arm"
+      ;;
+    *armv8*) # unconfirmed
+      echo "aarch64"
+      ;;
+    *)
+      echo "Unknown processor architecture. Please file a bug report."
+      ;;
+  esac
+}
+
 function set_java_17 () {
   if ! [ -d /usr/lib/jvm/jdk-17* ]; then
-    echo "Downloading JDK 1.17"
-    curl -L https://github.com/adoptium/temurin17-binaries/releases/download/jdk-17.0.1%2B12/OpenJDK17U-jdk_x64_linux_hotspot_17.0.1_12.tar.gz  | tar xz -C /usr/lib/jvm
+    CPU_ARCH=$(get_cpu_arch_for_java)
+    echo "Downloading JDK 1.17 $CPU_ARCH"
+    curl -L "https://github.com/adoptium/temurin17-binaries/releases/download/jdk-17.0.2%2B8/OpenJDK17U-jdk_${CPU_ARCH}_linux_hotspot_17.0.2_8.tar.gz"  | tar xz -C /usr/lib/jvm
   fi
 
   echo "set java version to 17"
@@ -21,8 +41,9 @@ function set_java_17 () {
 
 function set_java_16 () {
   if ! [ -d /usr/lib/jvm/jdk-16* ]; then
-    echo "Downloading JDK 1.16"
-    curl -L https://github.com/adoptium/temurin16-binaries/releases/download/jdk-16.0.2%2B7/OpenJDK16U-jdk_x64_linux_hotspot_16.0.2_7.tar.gz  | tar xz -C /usr/lib/jvm
+    CPU_ARCH=$(get_cpu_arch_for_java)
+    echo "Downloading JDK 1.16 $CPU_ARCH"
+    curl -L "https://github.com/adoptium/temurin16-binaries/releases/download/jdk-16.0.2%2B7/OpenJDK16U-jdk_${CPU_ARCH}_linux_hotspot_16.0.2_7.tar.gz"  | tar xz -C /usr/lib/jvm
   fi
 
   echo "set java version to 16"
@@ -33,20 +54,22 @@ function set_java_16 () {
 
 function set_java_11 () {
   if ! [ -d /usr/lib/jvm/jdk-11* ]; then
-    echo "Downloading JDK 1.11"
-    curl -L https://github.com/adoptium/temurin11-binaries/releases/download/jdk-11.0.13%2B8/OpenJDK11U-jdk_x64_linux_hotspot_11.0.13_8.tar.gz  | tar xz -C /usr/lib/jvm
+    CPU_ARCH=$(get_cpu_arch_for_java)
+    echo "Downloading JDK 1.11 $CPU_ARCH"
+    curl -L "https://github.com/adoptium/temurin11-binaries/releases/download/jdk-11.0.14.1%2B1/OpenJDK11U-jdk_${CPU_ARCH}_linux_hotspot_11.0.14.1_1.tar.gz"  | tar xz -C /usr/lib/jvm
   fi
 
-  echo "set java version to 16"
+  echo "set java version to 11"
   rm -f /usr/lib/jvm/default-jvm 
   ln -s /usr/lib/jvm/jdk-11* /usr/lib/jvm/default-jvm
 
 }
 
 function set_java_8 () {
   if ! [ -d /usr/lib/jvm/jdk8* ]; then
-    echo "Downloading JDK 1.8"
-    curl -L https://github.com/adoptium/temurin8-binaries/releases/download/jdk8u312-b07/OpenJDK8U-jdk_x64_linux_hotspot_8u312b07.tar.gz  | tar xz -C /usr/lib/jvm
+    CPU_ARCH=$(get_cpu_arch_for_java)
+    echo "Downloading JDK 1.8 $CPU_ARCH"
+    curl -L "https://github.com/adoptium/temurin8-binaries/releases/download/jdk8u322-b06/OpenJDK8U-jdk_${CPU_ARCH}_linux_hotspot_8u322b06.tar.gz"  | tar xz -C /usr/lib/jvm
   fi
 
   echo "set java version to 8"