Standard Debian base image

build/debian-base/Dockerfile

+# Copyright 2017 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+FROM scratch
+
+ADD rootfs.tar /
+
+CMD ["/bin/sh"]

build/debian-base/Dockerfile.build

+# Copyright 2017 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+FROM BASEIMAGE
+
+# If we're building for another architecture than amd64, the CROSS_BUILD_ placeholder is removed so
+# e.g. CROSS_BUILD_COPY turns into COPY
+# If we're building normally, for amd64, CROSS_BUILD lines are removed
+CROSS_BUILD_COPY qemu-ARCH-static /usr/bin/
+
+ENV DEBIAN_FRONTEND=noninteractive
+
+# Smaller package install size.
+COPY excludes /etc/dpkg/dpkg.cfg.d/excludes
+
+# Convenience script for building on this base image.
+COPY clean-install /usr/local/bin/clean-install
+
+# Update system packages.
+RUN apt-get update \
+    && apt-get dist-upgrade -y
+
+# Hold required packages to avoid breaking the installation of packages
+RUN apt-mark hold apt gnupg adduser passwd libsemanage1
+
+# Remove unnecessary packages.
+# This list was generated manually by listing the installed packages (`apt list --installed`),
+# then running `apt-cache rdepends --installed --no-recommends` to find the "root" packages.
+# The root packages were evaluated based on whether they were needed in the container image.
+# Several utilities (e.g. ping) were kept for usefulness, but may be removed in later versions.
+RUN echo "Yes, do as I say!" | apt-get purge \
+    bash \
+    debconf-i18n \
+    e2fslibs \
+    e2fsprogs \
+    gcc-4.8-base \
+    init \
+    initscripts \
+    libcap2-bin \
+    libkmod2 \
+    libmount1 \
+    libsmartcols1 \
+    libudev1 \
+    libblkid1 \
+    libncursesw5 \
+    libprocps3 \
+    libslang2 \
+    libss2 \
+    libtext-charwidth-perl libtext-iconv-perl libtext-wrapi18n-perl \
+    ncurses-base \
+    ncurses-bin \
+    systemd \
+    systemd-sysv \
+    sysv-rc \
+    tzdata
+
+# No-op stubs replace some unnecessary binaries that may be depended on in the install process (in
+# particular we don't run an init process).
+WORKDIR /usr/local/bin
+RUN touch noop && \
+    chmod 555 noop && \
+    ln -s noop runlevel && \
+    ln -s noop invoke-rc.d && \
+    ln -s noop update-rc.d
+WORKDIR /
+
+# Cleanup cached and unnecessary files.
+RUN apt-get autoremove -y && \
+    apt-get clean -y && \
+    tar -czf /usr/share/copyrights.tar.gz /usr/share/common-licenses /usr/share/doc/*/copyright && \
+    rm -rf \
+        /usr/share/doc \
+        /usr/share/man \
+        /usr/share/info \
+        /usr/share/locale \
+        /var/lib/apt/lists/* \
+        /var/log/* \
+        /var/cache/debconf/* \
+        /usr/share/common-licenses* \
+        /usr/share/bash-completion \
+        ~/.bashrc \
+        ~/.profile \
+        /etc/systemd \
+        /lib/lsb \
+        /lib/udev \
+        /usr/lib/x86_64-linux-gnu/gconv/IBM* \
+        /usr/lib/x86_64-linux-gnu/gconv/EBC* && \
+    mkdir -p /usr/share/man/man1 /usr/share/man/man2 \
+        /usr/share/man/man3 /usr/share/man/man4 \
+        /usr/share/man/man5 /usr/share/man/man6 \
+        /usr/share/man/man7 /usr/share/man/man8

build/debian-base/Makefile

+# Copyright 2017 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+all: build
+
+REGISTRY ?= gcr.io/google-containers
+IMAGE ?= debian-base
+BUILD_IMAGE ?= debian-build
+
+TAG ?= 0.1.0
+
+TAR_FILE ?= rootfs.tar
+ARCH?=amd64
+TEMP_DIR:=$(shell mktemp -d)
+QEMUVERSION=v2.7.0
+
+ifeq ($(ARCH),amd64)
+	BASEIMAGE?=debian:jessie
+endif
+ifeq ($(ARCH),arm)
+	BASEIMAGE?=armhf/debian:jessie
+	QEMUARCH=arm
+endif
+ifeq ($(ARCH),arm64)
+	BASEIMAGE?=aarch64/debian:jessie
+	QEMUARCH=aarch64
+endif
+ifeq ($(ARCH),ppc64le)
+	BASEIMAGE?=ppc64le/debian:jessie
+	QEMUARCH=ppc64le
+endif
+ifeq ($(ARCH),s390x)
+	BASEIMAGE?=s390x/debian:jessie
+	QEMUARCH=s390x
+endif
+
+build: clean
+	cp ./* $(TEMP_DIR)
+	cat Dockerfile.build \
+		| sed "s|BASEIMAGE|$(BASEIMAGE)|g" \
+		| sed "s|ARCH|$(QEMUARCH)|g" \
+		> $(TEMP_DIR)/Dockerfile.build
+
+ifeq ($(ARCH),amd64)
+	# When building "normally" for amd64, remove the whole line, it has no part in the amd64 image
+	sed "/CROSS_BUILD_/d" $(TEMP_DIR)/Dockerfile.build > $(TEMP_DIR)/Dockerfile.build.tmp
+else
+	# When cross-building, only the placeholder "CROSS_BUILD_" should be removed
+	# Register /usr/bin/qemu-ARCH-static as the handler for ARM binaries in the kernel
+	docker run --rm --privileged multiarch/qemu-user-static:register --reset
+	curl -sSL https://github.com/multiarch/qemu-user-static/releases/download/$(QEMUVERSION)/x86_64_qemu-$(QEMUARCH)-static.tar.gz | tar -xz -C $(TEMP_DIR)
+	sed "s/CROSS_BUILD_//g" $(TEMP_DIR)/Dockerfile.build > $(TEMP_DIR)/Dockerfile.build.tmp
+endif
+	mv $(TEMP_DIR)/Dockerfile.build.tmp $(TEMP_DIR)/Dockerfile.build
+
+	docker build --pull -t $(BUILD_IMAGE) -f $(TEMP_DIR)/Dockerfile.build $(TEMP_DIR)
+	docker create --name $(BUILD_IMAGE) $(BUILD_IMAGE)
+	docker export $(BUILD_IMAGE) > $(TEMP_DIR)/$(TAR_FILE)
+	docker build -t $(REGISTRY)/$(IMAGE)-$(ARCH):$(TAG) $(TEMP_DIR)
+	rm -rf $(TEMP_DIR)
+
+clean:
+	docker rmi -f $(REGISTRY)/$(IMAGE)-$(ARCH):$(TAG) || true
+	docker rmi -f $(BUILD_IMAGE)   || true
+	docker rm  -f $(BUILD_IMAGE)   || true

build/debian-base/README.md

+# Kubernetes Debian Base
+
+The Kubernetes debian-base image provides a common base for Kubernetes system images that require
+external dependencies (such as `iptables`, `sh`, or anything that is more than a static go-binary).
+
+This image differs from the standard debian image by removing a lot of packages and files that are
+generally not necessary in containers. The end result is an image that is just over 40 MB, down from
+123 MB.
+
+The image also provides a convenience script `/usr/local/bin/clean-install` that encapsulates the
+process of updating apt repositories, installing the packages, and then cleaning up unnecessary
+caches & logs.

build/debian-base/clean-install

+#!/bin/sh
+
+# Copyright 2017 The Kubernetes Authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# A script encapsulating a common Dockerimage pattern for installing packages
+# and then cleaning up the unnecessary install artifacts.
+# e.g. clean-install iptables ebtables conntrack
+
+set -o errexit
+
+if [ $# = 0 ]; then
+  echo >&2 "No packages specified"
+  exit 1
+fi
+
+apt-get update
+apt-get install -y --no-install-recommends $@
+apt-get clean -y
+rm -rf \
+   /var/cache/debconf/* \
+   /var/lib/apt/lists/* \
+   /var/log/*

build/debian-base/excludes

+path-exclude /usr/share/doc/*
+path-include /usr/share/doc/*/copyright
+path-exclude /usr/share/groff/*
+path-exclude /usr/share/i18n/locales/*
+path-include /usr/share/i18n/locales/en_US*
+path-exclude /usr/share/info/*
+path-exclude /usr/share/locale/*
+path-include /usr/share/locale/en_US*
+path-include /usr/share/locale/locale.alias
+path-exclude /usr/share/man/*