Use debian-base instead of distroless for conformance image

The `diff` binary (required by the `kubectl diff` e2e test) gets
statically or dynamically linked based on the used glibc version. We
cannot really predict that behavior for the various platforms of
debian-base and therefore cannot copy the binary around. This means that
distroless is not a great choice for the conformance image unless we
stop relying on `diff`.

This means we now switch back to `debian-base` for the conformance image
to simplify the build process and reduce the amount of moving parts.

Signed-off-by: Sascha Grunert <[email protected]>

Author: saschagrunert

test/conformance/image/Dockerfile

@@ -12,19 +12,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-ARG BASEIMAGE
 ARG RUNNERIMAGE
-
-FROM ${BASEIMAGE} as debbase
-
 FROM ${RUNNERIMAGE}
 
-# This is a dependency for `kubectl diff` tests
-COPY --from=debbase /usr/bin/diff /usr/local/bin/
-COPY --from=debbase /lib/x86_64-linux-gnu/libc.so.6 /lib/x86_64-linux-gnu
-COPY --from=debbase /lib/x86_64-linux-gnu/libpthread.so.0 /lib/x86_64-linux-gnu
-COPY --from=debbase /lib64/ld-linux-x86-64.so.2 /lib64
-
 COPY cluster /kubernetes/cluster
 COPY ginkgo /usr/local/bin/
 COPY e2e.test /usr/local/bin/

test/conformance/image/Makefile

@@ -34,12 +34,7 @@ CLUSTER_DIR?=$(shell pwd)/../../../cluster/
 # This is defined in root Makefile, but some build contexts do not refer to them
 KUBE_BASE_IMAGE_REGISTRY?=registry.k8s.io
 BASE_IMAGE_VERSION?=bookworm-v1.0.0
-BASEIMAGE?=${KUBE_BASE_IMAGE_REGISTRY}/build-image/debian-base-${ARCH}:${BASE_IMAGE_VERSION}
-
-# Keep debian releases (e.g. debian 11 == bullseye) consistent 
-# between BASE_IMAGE_VERSION and DISTROLESS_IMAGE images
-DISTROLESS_IMAGE?=base-debian11
-RUNNERIMAGE?=gcr.io/distroless/${DISTROLESS_IMAGE}:latest
+RUNNERIMAGE?=${KUBE_BASE_IMAGE_REGISTRY}/build-image/debian-base-${ARCH}:${BASE_IMAGE_VERSION}
 
 TEMP_DIR:=$(shell mktemp -d -t conformance-XXXXXX)
 
@@ -68,7 +63,6 @@ endif
 		--load \
 		--pull \
 		-t ${REGISTRY}/conformance-${ARCH}:${VERSION} \
-		--build-arg BASEIMAGE=$(BASEIMAGE) \
 		--build-arg RUNNERIMAGE=$(RUNNERIMAGE) \
 		${TEMP_DIR}
 	rm -rf "${TEMP_DIR}"