Import alpine building script from Timothee

alpine-rebuild-initramfs.sh

@@ -0,0 +1,59 @@
+#!/bin/sh
+
+set -e
+set -x
+
+MAJOR_VERSION=3.10
+MINOR_VERSION=3
+IMAGE=alpine-minirootfs-$MAJOR_VERSION.$MINOR_VERSION-x86_64.tar.gz
+SSH_KEYS=$(cat ~/.ssh/id_rsa.pub)
+RESOLVCONF=/etc/resolv.conf
+
+working_directory=$(dirname $0)
+rootfs_tmpdir=$(mktemp -d)
+rootfs_url="http://dl-cdn.alpinelinux.org/alpine/v$MAJOR_VERSION/releases/x86_64/$IMAGE"
+
+run_root () {
+    chroot $rootfs_tmpdir /usr/bin/env \
+        PATH=/bin:/sbin \
+        /bin/sh -c "$*"
+}
+
+if [ "$(whoami)" != 'root' ]; then
+    echo "This script must be run as root." >&2
+    exit 1
+fi
+
+# Download, extract inital rootfs.
+curl "$rootfs_url" -o "$working_directory/$IMAGE"
+tar xf $IMAGE -C $rootfs_tmpdir
+
+# Add SSH keys
+run_root mkdir root/.ssh
+echo $SSH_KEYS > $rootfs_tmpdir/root/.ssh/authorized_keys
+run_root chmod 0600 root/.ssh/authorized_keys
+run_root chmod 0700 root/.ssh
+
+# Import local resolv.conf.
+cat $RESOLVCONF > $rootfs_tmpdir/etc/resolv.conf
+
+# Make sure init is found by the kernel.
+run_root ln -s /sbin/init /init
+
+# Layer atop base rootfs.
+run_root apk update
+run_root apk upgrade
+run_root apk add openssh linux-vanilla openrc udev
+run_root rc-update add udev
+run_root rc-update add sshd
+
+# Generate iniramfs image
+(cd $rootfs_tmpdir; find . | cpio -H newc -o | gzip -9 > "$working_directory/alpine-initramfs.gz")
+cp $rootfs_tmpdir/boot/vmlinuz-vanilla "$working_directory/alpine-kernel"
+
+# Upload to netboot server.
+scp alpine-initramfs.gz alpine-kernel root@netboot.hack4glarus.ungleich.cloud:/var/www/html/
+
+# Cleanup.
+rm -r $rootfs_tmpdir
+(cd "$working_directory/"; rm vmlinuz-vanilla alpine-kernel $IMAGE)