Optimize Docker image size using minimal distroless base with essential libraries

Author: balcsida

Dockerfile

@@ -10,10 +10,23 @@ WORKDIR /go/src/github.com/Azure/acr-cli
 COPY . .
 RUN make binaries && mv bin/acr /usr/bin/acr
 
-FROM mcr.microsoft.com/azurelinux/base/core:3.0
-RUN tdnf check-update \
-    && tdnf --refresh install -y \
-        ca-certificates-microsoft \
-    && tdnf clean all
+# Manually copy essential libraries that Go FIPS binaries typically need
+RUN mkdir -p /tmp/libs && \
+    cp /lib64/libc.so.6 /tmp/libs/ 2>/dev/null || true && \
+    cp /lib64/libdl.so.2 /tmp/libs/ 2>/dev/null || true && \
+    cp /lib64/libpthread.so.0 /tmp/libs/ 2>/dev/null || true && \
+    cp /lib64/librt.so.1 /tmp/libs/ 2>/dev/null || true && \
+    cp /lib64/libresolv.so.2 /tmp/libs/ 2>/dev/null || true && \
+    cp /lib64/libssl.so* /tmp/libs/ 2>/dev/null || true && \
+    cp /lib64/libcrypto.so* /tmp/libs/ 2>/dev/null || true && \
+    cp /usr/lib64/libssl.so* /tmp/libs/ 2>/dev/null || true && \
+    cp /usr/lib64/libcrypto.so* /tmp/libs/ 2>/dev/null || true
+
+FROM mcr.microsoft.com/azurelinux/distroless/minimal:3.0
+# Copy the dynamic linker
+COPY --from=acr-cli /lib/ld-linux-aarch64.so.1 /lib/
+# Copy essential libraries
+COPY --from=acr-cli /tmp/libs/ /lib64/
+# Copy the binary
 COPY --from=acr-cli /usr/bin/acr /usr/bin/acr
 ENTRYPOINT [ "/usr/bin/acr" ]