Reduce SONiC migration partition from 8G to 1G. (#1343)

* Reduce SONiC migration partition from 8G to 1G.

* Changes to create 1G partition with ability to resize post migration.

* Remove redundant changes in varlog

* Use findfs to interpret root. Move resize in case cmdline params are reordered

build_debian.sh

@@ -133,6 +133,10 @@ sudo chmod +x $FILESYSTEM_ROOT/etc/initramfs-tools/hooks/setfacl
 sudo cp files/initramfs-tools/arista-net $FILESYSTEM_ROOT/etc/initramfs-tools/scripts/init-premount/arista-net
 sudo chmod +x $FILESYSTEM_ROOT/etc/initramfs-tools/scripts/init-premount/arista-net
 
+# Hook into initramfs: resize root partition after migration from another NOS to SONiC on Dell switches
+sudo cp files/initramfs-tools/resize-rootfs $FILESYSTEM_ROOT/etc/initramfs-tools/scripts/init-premount/resize-rootfs
+sudo chmod +x $FILESYSTEM_ROOT/etc/initramfs-tools/scripts/init-premount/resize-rootfs
+
 ## Hook into initramfs: after partition mount and loop file mount
 ## 1. Prepare layered file system
 ## 2. Bind-mount docker working directory (docker aufs cannot work over aufs rootfs)

build_image.sh

@@ -56,7 +56,7 @@ elif [ "$IMAGE_TYPE" = "raw" ]; then
     echo "Creating SONiC raw partition : $OUTPUT_RAW_IMAGE of size $RAW_IMAGE_DISK_SIZE MB"
     fallocate -l "$RAW_IMAGE_DISK_SIZE"M $OUTPUT_RAW_IMAGE
 
-    ## Generate a compressed 8GB partition dump that can be used to 'dd' in-lieu of using the onie-nos-installer
+    ## Generate a partition dump that can be used to 'dd' in-lieu of using the onie-nos-installer
     ## Run the installer 
     ## The 'build' install mode of the installer is used to generate this dump.
     sudo chmod a+x $OUTPUT_ONIE_IMAGE

files/initramfs-tools/mke2fs

@@ -20,6 +20,8 @@ esac
 copy_exec /sbin/mke2fs
 copy_exec /sbin/sfdisk
 copy_exec /sbin/fdisk
+copy_exec /sbin/resize2fs
+copy_exec /sbin/findfs
 
 fstypes="ext4 ext3"
 

files/initramfs-tools/resize-rootfs

@@ -0,0 +1,39 @@
+#!/bin/sh
+
+case $1 in
+    prereqs)
+        exit 0
+        ;;
+esac
+
+# Extract kernel parameters
+set -- $(cat /proc/cmdline)
+for x in "$@"; do
+    case "$x" in
+        root=*)
+            root_val="${x#root=}"
+            ;;
+        resize-rootfs)
+            need_resize=1
+            ;;
+    esac
+done
+
+if [ -n "$need_resize" ]; then
+    if [ -z "$root_val" ]; then
+        echo "ERROR: resize required but unable to get root location from command line"
+        exit 1
+    fi
+
+    root_dev=$(findfs $root_val)
+    if [ $? != 0 ]; then
+        echo "ERROR: resize required but findfs failed"
+        exit 1
+    fi
+
+    resize2fs -f $root_dev
+    if [ $? != 0 ]; then
+        echo "ERROR: Unable to resize the root file system. Manual intervention needed to fix the issue."
+        exit 1
+    fi
+fi

onie-image.conf

@@ -31,7 +31,7 @@ OUTPUT_ONIE_IMAGE=target/sonic-$TARGET_MACHINE.bin
 OUTPUT_RAW_IMAGE=target/sonic-$TARGET_MACHINE.raw
 
 ### Raw image size in MB
-RAW_IMAGE_DISK_SIZE=8192
+RAW_IMAGE_DISK_SIZE=1024
 
 ## Output file name for aboot installer
 OUTPUT_ABOOT_IMAGE=target/sonic-aboot-$TARGET_MACHINE.swi