LinuxQuestions.org - squashfs system multiboot from sd/usb

Hello.

For a past few days I'm struggling to create sd card with few root filesystems to choose from on boot. The idea is to convert running system to squashfs file and put it on sd card. Systems should be readonly and any additional files added later should be kept on rw partition mounted on start. Any other files should be kept in RAM and lost after reboot. So partitions should be like this:

1st - vmlinuz, kernel, grub files, os1.squash, os2.squash and so on
2nd - mounted to, for instance to /mnt/ after boot with extra files available across systems (after succeeding booting OS at all :))

For testing purposes I'm using vmware, with one HDD with centos 6.5 installed and run from it, and second HDD simulating SD card which is plugged to base OS, then unplugged and run by its own on another virtual machine.

So what I do is:

Rsync running system to /root/sqfs/

Code:

sudo rsync -av --one-file-system --exclude=/proc/* --exclude=/dev/* --exclude=/sys/* --exclude=/tmp/* --exclude=/home/* --exclude=/lost+found --exclude=/var/tmp/* --exclude=/boot/grub/* --exclude=/root/* --exclude=/var/mail/* --exclude=/var/spool/* --exclude=/media/* --exclude=/etc/fstab --exclude=/etc/mtab --exclude=/etc/hosts --exclude=/etc/shadow* --exclude=/etc/gshadow* --exclude=/root/sqfs/ --exclude=/etc/resolv.conf --exclude=/etc/hostname / sqfs/

creating squashfs file from it

Code:

sudo mksquashfs /root/sqfs/ /root/os1.squash -noappend

using fdisk on second HDD to create two primary partitions and make 1st bootable

creating filesystems on them

Code:

mkfs.ext2 /dev/sdb1

mkfs.ext3 /dev/sdb2

mounting partitions and moving squash fs there

Code:

mkdir /mnt/sq1

mkdir /mnt/sq2



mount /dev/sdb1 /mnt/sq1

mount /dev/sdb2 /mnt/sq2



cp /root/os1.squash /mnt/sq1/

copy kernel

Code:

cp /boot/vmlinuz-2.6.32-431.el6.x86_64 /mnt/sq1/vmlinuz

cp /boot/initramfs-2.6.32-431.el6.x86_64.img /mnt/sq1/initrd.img

instaling grub

Code:

grub-install --no-floppy --root-directory=/mnt/sq1/ /dev/sdb1

and editing grub in /mnt/sq1/boot/grub/grub.cfg

Code:

default=0

timeout=5

hiddenmenu

title os1

        kernel /vmlinuz root=live:LABEL=os1.squash rootfstype=auto live_dir=/ ro liveimg nodiskmount nolvmmount rd.luks=0 rd.lvm=0 rd.md=0 rd.dm=0

        initrd /initrd.img

So I end up with structure like this:

Code:

/mnt/sq1

├── boot

│** └── grub

│**    ├── device.map

│**    ├── e2fs_stage1_5

│**    ├── fat_stage1_5

│**    ├── ffs_stage1_5

│**    ├── grub.conf

│**    ├── iso9660_stage1_5

│**    ├── jfs_stage1_5

│**    ├── minix_stage1_5

│**    ├── reiserfs_stage1_5

│**    ├── stage1

│**    ├── stage2

│**    ├── ufs2_stage1_5

│**    ├── vstafs_stage1_5

│**    └── xfs_stage1_5

├── initrd.img

├── os1.squash

└── vmlinuz

Then after boot an choosing os1 dracut throws warning

Code:

dracut Warning: No root device "block:/dev/mapper/live-rw" found

Most probably I don't use kernel parameters right, can u please give me hint how it supposed be done?