use extlinux instead of grub2

Dockerfile

@@ -1,9 +1,8 @@
-FROM debian:jessie
+FROM alpine
+RUN apk update && apk add coreutils util-linux bash parted syslinux e2fsprogs
 COPY ./scripts/installer /scripts
 COPY ./scripts/version /scripts/
-RUN /scripts/bootstrap
 
-COPY ./dist/artifacts/vmlinuz /dist/vmlinuz
-COPY ./dist/artifacts/initrd  /dist/initrd
+COPY ./dist/artifacts/vmlinuz ./dist/artifacts/initrd /dist/
 
 ENTRYPOINT ["/scripts/lay-down-os"]

scripts/installer/bootstrap

@@ -1,6 +0,0 @@
-#!/bin/bash
-
-export DEBIAN_FRONTEND=noninteractive
-
-apt-get update 
-apt-get install -y grub2 parted

scripts/installer/lay-down-os

@@ -2,10 +2,11 @@
 set -e -x
 
 . $(dirname $0)/version
+VERSION=${VERSION:?"VERSION not set"}
 
 while getopts "i:f:c:d:t:r:o:p:" OPTION
 do
-    case $OPTION in 
+    case ${OPTION} in
         i) DIST="$OPTARG" ;;
         f) FILES="$OPTARG" ;;
         c) CLOUD_CONFIG="$OPTARG" ;;
@@ -56,43 +57,41 @@ mount_device()
         mount_opts=${PARTITION}
     fi
 
-    mount $mount_opts ${BASE_DIR}
+    mount ${mount_opts} ${BASE_DIR}
     trap "umount ${BASE_DIR}" EXIT
 }
 
 create_boot_dirs()
 {
     mkdir -p ${BASE_DIR}/boot/grub
+    mkdir -p ${BASE_DIR}/boot/extlinux
 }
 
-install_grub() {
-    grub-install --boot-directory=${BASE_DIR}/boot ${DEVICE}
+install_extlinux() {
+    extlinux -i ${BASE_DIR}/boot/extlinux
+    dd if=/usr/share/syslinux/mbr.bin of=${DEVICE}
 }
 
-grub2_config(){
-    local grub_cfg=${BASE_DIR}/boot/grub/grub.cfg
+extlinux_config(){
+    local extlinux_conf=${BASE_DIR}/boot/extlinux/extlinux.conf
     local append_line="${1}"
-cat >$grub_cfg <<EOF
-set default="0"
-set timeout="1"
-#set fallback=1
-
-menuentry "RancherOS-current" {
-  set root=(hd0,msdos1)
-  linux /boot/vmlinuz-${VERSION}-rancheros ${append_line} console=ttyS0 console=tty0
-  initrd /boot/initrd-${VERSION}-rancheros
-}
+cat >${extlinux_conf} <<EOF
+default ros
+label ros
+    kernel /boot/vmlinuz-${VERSION}-rancheros
+    initrd /boot/initrd-${VERSION}-rancheros
+    append ${append_line} console=ttyS0 console=tty0
 
 EOF
 
-if [ ! -z $ROLLBACK_VERSION ]; then
-    sed -i 's/^#set/set/' ${grub_cfg}
-cat >>$grub_cfg <<EOF
-menuentry "RancherOS-rollback" {
-  set root=(hd0,msdos1)
-  linux /boot/vmlinuz-${ROLLBACK_VERSION}-rancheros ${append_line} console=ttyS0 console=tty0
-  initrd /boot/initrd-${ROLLBACK_VERSION}-rancheros
-}
+if [ ! -z ${ROLLBACK_VERSION} ]; then
+    sed -i 's/^#set/set/' ${extlinux_conf}
+cat >>${extlinux_conf} <<EOF
+label ros-fallback
+    kernel /boot/vmlinuz-${ROLLBACK_VERSION}-rancheros
+    initrd /boot/initrd-${ROLLBACK_VERSION}-rancheros
+    append ${append_line} console=ttyS0 console=tty0
+
 EOF
 fi
 
@@ -100,15 +99,15 @@ fi
 
 install_rancher()
 {
-    cp ${DIST}/initrd /mnt/new_img/boot/initrd-${VERSION}-rancheros
-    cp ${DIST}/vmlinuz /mnt/new_img/boot/vmlinuz-${VERSION}-rancheros
+    cp ${DIST}/initrd ${BASE_DIR}/boot/initrd-${VERSION}-rancheros
+    cp ${DIST}/vmlinuz ${BASE_DIR}/boot/vmlinuz-${VERSION}-rancheros
 }
 
 pvgrub_config()
 {
-    local grub_file=/mnt/new_img/boot/grub/menu.lst
+    local grub_file=${BASE_DIR}/boot/grub/menu.lst
     local append_line="${1}"
-cat > $grub_file<<EOF
+cat > ${grub_file}<<EOF
 default 0
 timeout 0
 #fallback 1
@@ -122,9 +121,9 @@ initrd /boot/initrd-${VERSION}-rancheros
 
 EOF
 
-if [ ! -z $ROLLBACK_VERSION ]; then
-    sed -i 's/^#\(fallback\)/\1/' $grub_file
-cat >> $grub_file<<EOF
+if [ ! -z ${ROLLBACK_VERSION} ]; then
+    sed -i 's/^#\(fallback\)/\1/' ${grub_file}
+cat >> ${grub_file}<<EOF
 title RancherOS ${ROLLBACK_VERSION}-(rollback)
 root (hd0)
 kernel /boot/vmlinuz-${ROLLBACK_VERSION}-rancheros ${append_line} console=ttyS0 console=tty0
@@ -145,21 +144,21 @@ if [ -n ${ENV} ]; then
     case ${ENV} in
         "generic")
             format_and_mount
-            install_grub
-            /scripts/seed-data $BASE_DIR $CLOUD_CONFIG $FILES
+            install_extlinux
+            /scripts/seed-data ${BASE_DIR} ${CLOUD_CONFIG} ${FILES}
             ;;
         "amazon-ebs-pv"|"amazon-ebs-hvm")
             format_and_mount
             if [ "${ENV}" == "amazon-ebs-hvm" ]; then
-                install_grub
+                install_extlinux
             fi
             # AWS Networking recommends disabling.
-            /scripts/seed-data $BASE_DIR $CLOUD_CONFIG $FILES
+            /scripts/seed-data ${BASE_DIR} ${CLOUD_CONFIG} ${FILES}
             ;;
         "googlecompute")
             format_and_mount
-            install_grub
-            /scripts/seed-data $BASE_DIR $CLOUD_CONFIG $FILES
+            install_extlinux
+            /scripts/seed-data ${BASE_DIR} ${CLOUD_CONFIG} ${FILES}
             ;;
         "bootstrap")
             mount_device true
@@ -177,6 +176,6 @@ if [ -n ${ENV} ]; then
     esac
 fi
 
-grub2_config "${KERNEL_ARGS}"
+extlinux_config "${KERNEL_ARGS}"
 pvgrub_config "${KERNEL_ARGS}"
 install_rancher

scripts/installer/set-disk-partitions

@@ -39,5 +39,6 @@ p
 1
 
 
+a
 w
 EOF