Add scripts and documentation for building a CentOS image.

Signed-off-by: dlorenc <[email protected]>

.gitignore

@@ -5,3 +5,4 @@ mkdebootstrap/mkimage/
 mkdebootstrap/Dockerfile
 bazel-*
 rootfs.tar.gz
+centos/layer.tar

centos/Dockerfile

@@ -0,0 +1,3 @@
+FROM scratch
+ADD layer.tar /
+CMD ["/bin/bash"]

centos/Dockerfile.build

@@ -0,0 +1,4 @@
+FROM centos
+COPY build.sh .
+COPY chroot.sh /target/
+

centos/README.md

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+## CentOS
+
+This directory contains scripts and Dockerfiles for building a CentOS container image.
+
+### Overview
+
+We bootstrap the image following a process based on a combination of https://wiki.centos.org/HowTos/ManualInstall
+and https://github.com/CentOS/sig-cloud-instance-build/blob/master/docker/centos-7.ks.
+
+We avoid using kickstart to make it easier to run in a container environment like Cloud Build, but still reuse the
+package list and cleanup steps from the kickstart installation.
+
+To build an image:
+
+```shell
+gcloud builds submit --config=cloudbuild.yaml
+```
+
+To build locally:
+
+```shell
+docker build . -f Dockerfile.build -t builder
+
+docker run --privileged -v $(pwd):/workspace builder /build.sh
+
+docker build . -t mycentosimage
+```

centos/build.sh

@@ -0,0 +1,27 @@
+#!/bin/bash
+
+# This script sets up a bootstrapped CentOS chroot and saves it as a tarball.
+
+mkdir /target
+rpm --nodeps --root /target/ -i http://mirror.centos.org/centos/7/os/x86_64/Packages/centos-release-7-5.1804.el7.centos.x86_64.rpm
+cp -f /etc/resolv.conf /target/etc
+
+yum -q -y --installroot=/target --releasever=7 install yum
+cp -f /etc/yum.conf /target/etc/
+mkdir -p /target/dev
+mount --bind /dev/ /target/dev/
+mount -t proc procfs /target/proc/
+mount -t sysfs sysfs /target/sys/
+
+# Execute the chroot script.
+chroot /target ./chroot.sh
+
+# Cleanup and save as a tar.
+umount /target/dev/
+umount /target/proc/
+umount /target/sys/
+rm /target/chroot.sh
+
+tar -C /target -cf /workspace/layer.tar .
+
+

centos/chroot.sh

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+#!/bin/bash
+
+# This script runs inside a chroot and sets up a bootstrapped centos image.
+
+yum -y -q --releasever=7 install yum centos-release
+yum install -q -y bind-utils     bash     yum     vim-minimal     centos-release     less     iputils     iproute     systemd     rootfiles     tar     passwd     yum-utils     yum-plugin-ovl    hostname
+yum -q -y erase kernel*     *firmware     firewalld-filesystem     os-prober     gettext*     GeoIP     bind-license     freetype     libteam     teamd
+rpm -e kernel
+yum -y remove bind-libs bind-libs-lite dhclient dhcp-common dhcp-libs   dracut-network e2fsprogs e2fsprogs-libs ebtables ethtool file   firewalld freetype gettext gettext-libs groff-base grub2 grub2-tools   grubby initscripts iproute iptables kexec-tools libcroco libgomp   libmnl libnetfilter_conntrack libnfnetlink libselinux-python lzo   libunistring os-prober python-decorator python-slip python-slip-dbus   snappy sysvinit-tools which linux-firmware GeoIP firewalld-filesystem   qemu-guest-agent
+yum clean all
+rm -rf /var/cache/yum
+rm -rf /boot
+rm -rf /etc/firewalld
+passwd -l root
+echo 'container' > /etc/yum/vars/infra
+rm -rf /var/cache/yum/x86_64
+rm -f /tmp/ks-script*
+rm -rf /etc/sysconfig/network-scripts/ifcfg-*
+rm -rf /etc/udev/hwdb.bin
+rm -rf /usr/lib/udev/hwdb.d/*
+:> /etc/machine-id
+umount /run
+systemd-tmpfiles --create --boot
+rm /var/run/nologin
+rpm --rebuilddb
+rm /etc/resolv.conf
+
+rm -rf /root/.bash_history

centos/cloudbuild.yaml

@@ -0,0 +1,8 @@
+steps:
+- name: 'docker'
+  args: ['build', '.', '-f', 'Dockerfile.build', '-t', 'builder']
+- name: 'builder'
+  args: ['/build.sh']
+- name: 'docker'
+  args: ['build', '.', '-t', 'gcr.io/$PROJECT_ID/centos7:$COMMIT_SHA']
+images: ['gcr.io/$PROJECT_ID/centos7:$COMMIT_SHA']

centos/release_cloudbuild.yaml

@@ -0,0 +1,8 @@
+steps:
+- name: 'docker'
+  args: ['build', '.', '-f', 'Dockerfile.build', '-t', 'builder']
+- name: 'builder'
+  args: ['/build.sh']
+- name: 'docker'
+  args: ['build', '.', '-t', 'gcr.io/$PROJECT_ID/centos7:$_TAG_NAME']
+images: ['gcr.io/$PROJECT_ID/centos7:$_TAG_NAME']