Use GLIBC 2.34 compatible knockd for Java 17 images and older (#4158)

itzg · web-flow · commit 641f19879aa9 · 2026-07-12T21:48:11.000-05:00
diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
@@ -49,6 +49,8 @@ jobs:
             baseImage: eclipse-temurin:25-jre-alpine
             platforms: linux/amd64,linux/arm64
             mcVersion: latest
+            # For GLIBC_2.34 support (and Alpine)
+            knockdRepoOrg: Metalcape/knock
           - variant: java25-jdk
             baseImage: eclipse-temurin:25
             platforms: linux/amd64,linux/arm64
@@ -66,37 +68,49 @@ jobs:
             baseImage: eclipse-temurin:21-jre-alpine
             platforms: linux/amd64,linux/arm64
             mcVersion: 1.21.11
+            # For GLIBC_2.34 support (and Alpine)
+            knockdRepoOrg: Metalcape/knock
         # JAVA 17:
           - variant: java17
             # jammy doesn't work until minecraft updates to https://github.com/netty/netty/issues/12343
             baseImage: eclipse-temurin:17-jre-focal
             platforms: linux/amd64,linux/arm/v7,linux/arm64
             mcVersion: 1.20.4
+            # For GLIBC_2.34 support (and Alpine)
+            knockdRepoOrg: Metalcape/knock
         # JAVA 16
           - variant: java16
             baseImage: adoptopenjdk:16-jre-hotspot
             platforms: linux/amd64,linux/arm/v7,linux/arm64
             mcVersion: 1.16.5
+            # For GLIBC_2.34 support
+            knockdRepoOrg: Metalcape/knock
             # Pin version for pre-Java 17
             mcHelperVersion: 1.51.3-java8
         # JAVA 11
           - variant: java11
             baseImage: adoptopenjdk:11-jre-hotspot
             platforms: linux/amd64,linux/arm/v7,linux/arm64
             mcVersion: 1.16.4
+            # For GLIBC_2.34 support
+            knockdRepoOrg: Metalcape/knock
             # Pin version for pre-Java 17
             mcHelperVersion: 1.51.3-java8
         # JAVA 8: NOTE: Unable to go past 8u312 because of Forge dependencies
           - variant: java8
             baseImage: eclipse-temurin:8u312-b07-jre-focal
             platforms: linux/amd64,linux/arm/v7,linux/arm64
             mcVersion: 1.12.2
+            # For GLIBC_2.34 support
+            knockdRepoOrg: Metalcape/knock
             # Pin version for Java 8, also be sure to set in verify-pr.yml
             mcHelperVersion: 1.51.3-java8
           - variant: java8-jdk
             baseImage: eclipse-temurin:8u312-b07-jdk-focal
             platforms: linux/amd64,linux/arm64
             mcVersion: 1.12.2
+            # For GLIBC_2.34 support
+            knockdRepoOrg: Metalcape/knock
             # Pin version for Java 8, also be sure to set in verify-pr.yml
             mcHelperVersion: 1.51.3-java8
     env:
@@ -161,6 +175,7 @@ jobs:
           build-args: |
             BASE_IMAGE=${{ matrix.baseImage }}
             ${{ matrix.mcHelperVersion && format('MC_HELPER_VERSION={0}', matrix.mcHelperVersion) }}
+            ${{ matrix.knockdRepoOrg && format('KNOCKD_REPO_ORG={0}', matrix.knockdRepoOrg) }}
           cache-from: type=gha,scope=${{ matrix.variant }}
           # no cache-to to avoid cross-cache update from next build step
 
@@ -217,5 +232,6 @@ jobs:
             VERSION=${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.version'] }}
             REVISION=${{ fromJSON(steps.meta.outputs.json).labels['org.opencontainers.image.revision'] }}
             ${{ matrix.mcHelperVersion && format('MC_HELPER_VERSION={0}', matrix.mcHelperVersion) }}
+            ${{ matrix.knockdRepoOrg && format('KNOCKD_REPO_ORG={0}', matrix.knockdRepoOrg) }}
           cache-from: type=gha,scope=${{ matrix.variant }}
           cache-to: type=gha,mode=max,scope=${{ matrix.variant }}
diff --git a/.github/workflows/verify-pr.yml b/.github/workflows/verify-pr.yml
@@ -37,16 +37,22 @@ jobs:
             baseImage: eclipse-temurin:25-jre-alpine
             platforms: linux/amd64,linux/arm64
             mcVersion: latest
+            # For GLIBC_2.34 support (and Alpine)
+            knockdRepoOrg: Metalcape/knock
         # JAVA 17:
           - variant: java17
             # jammy doesn't work until minecraft updates to https://github.com/netty/netty/issues/12343
             baseImage: eclipse-temurin:17-jre-focal
             platforms: linux/amd64
             mcVersion: 1.20.4
+            # For GLIBC_2.34 support
+            knockdRepoOrg: Metalcape/knock
           - variant: java8
             baseImage: eclipse-temurin:8u312-b07-jre-focal
             platforms: linux/amd64
             mcVersion: 1.12.2
+            # For GLIBC_2.34 support
+            knockdRepoOrg: Metalcape/knock
             # Pin version for Java 8, be sure to also set in build.yml
             mcHelperVersion: 1.51.3-java8
     env:
@@ -71,6 +77,7 @@ jobs:
           build-args: |
             BASE_IMAGE=${{ matrix.baseImage }}
             ${{ matrix.mcHelperVersion && format('MC_HELPER_VERSION={0}', matrix.mcHelperVersion) }}
+            ${{ matrix.knockdRepoOrg && format('KNOCKD_REPO_ORG={0}', matrix.knockdRepoOrg) }}
           cache-from: type=gha,scope=${{ matrix.variant }}
 
       - name: Build for test
@@ -88,6 +95,7 @@ jobs:
           build-args: |
             BASE_IMAGE=${{ matrix.baseImage }}
             ${{ matrix.mcHelperVersion && format('MC_HELPER_VERSION={0}', matrix.mcHelperVersion) }}
+            ${{ matrix.knockdRepoOrg && format('KNOCKD_REPO_ORG={0}', matrix.knockdRepoOrg) }}
           cache-from: type=gha,scope=${{ matrix.variant }}
 
       - name: Run tests
diff --git a/Dockerfile b/Dockerfile
@@ -12,6 +12,8 @@ ARG EXTRA_DEB_PACKAGES=""
 ARG EXTRA_DNF_PACKAGES=""
 ARG EXTRA_ALPINE_PACKAGES=""
 ARG FORCE_INSTALL_PACKAGES=1
+ARG KNOCKD_VERSION=0.8.1
+ARG KNOCKD_REPO_ORG=Opvolger/knock
 RUN --mount=target=/build,source=build \
     TARGET=${TARGETARCH}${TARGETVARIANT} \
     /build/run.sh install-packages
diff --git a/build/alpine/install-packages.sh b/build/alpine/install-packages.sh
@@ -38,7 +38,7 @@ apk add --no-cache -U \
     ${EXTRA_ALPINE_PACKAGES}
 
 # Download and install patched knockd
-curl -fsSL -o /tmp/knock.tar.gz https://github.com/Metalcape/knock/releases/download/0.8.1/knock-0.8.1-alpine-amd64.tar.gz
+curl -fsSL -o /tmp/knock.tar.gz "https://github.com/${KNOCKD_REPO_ORG}/releases/download/${KNOCKD_VERSION}/knock-${KNOCKD_VERSION}-alpine-amd64.tar.gz"
 tar -xf /tmp/knock.tar.gz -C /usr/local/ && rm /tmp/knock.tar.gz
 ln -s /usr/local/sbin/knockd /usr/sbin/knockd
 setcap cap_net_raw=ep /usr/local/sbin/knockd
diff --git a/build/ubuntu/install-packages.sh b/build/ubuntu/install-packages.sh
@@ -38,7 +38,7 @@ apt-get install -y \
 apt-get clean
 
 # Download and install patched knockd
-curl -fsSL -o /tmp/knock.tar.gz https://github.com/Opvolger/knock/releases/download/0.8.1/knock-0.8.1-$TARGET.tar.gz
+curl -fsSL -o /tmp/knock.tar.gz "https://github.com/${KNOCKD_REPO_ORG}/releases/download/${KNOCKD_VERSION}/knock-${KNOCKD_VERSION}-$TARGET.tar.gz"
 tar -xf /tmp/knock.tar.gz -C /usr/local/ && rm /tmp/knock.tar.gz
 ln -s /usr/local/sbin/knockd /usr/sbin/knockd
 setcap cap_net_raw=ep /usr/local/sbin/knockd
