I like Armbian very much and use it often as small test box for tinkering with Linux. As I use my single board computers headless, I do not want to swap sdcards and reflash images.
Therefore I wrote small scripts that swap root filesystems that reside on an extra usb flash drive.
These scripts are released under the MIT License.
While these scripts have been actively tested on Orange Pi Zero with latest Armbian, it is quickly hacked to just work in my context to have a quick means of switching between fresh armbian installs on my single board computer.
There is currently not much error handling.
Also the armbian community stresses the importance of high-quality storage media. Especially sd cards. Storing and restoring a ext dump introduces a lot of extra write IOPS on the storage device. This may wear out the thumb drive more quickly.
Therefore I recommend this setup only for testing purposes and hope you are doing frequent backups to an offsite location for your important data.
While this method has been used quite often in an embedded environment, other techniques like ostree seem to be better suited and I hope it will be available on armbian in the future.
If you are looking for a robust method, I would recommend to go for ostree.
https://ostree.readthedocs.io/en/latest/
I for myself use two root filesystems for now and store docker overlays on the data partition.
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┌────────────────┐║┌───────────┐┌───────────┐┌───────────┐┌───────────┐
│ /dev/mmcblk0p1 │║│ /dev/sda1 ││ /dev/sda2 ││ /dev/sda3 ││ /dev/sda4 │
│ BOOT │║│ STAGING ││ ROOTA ││ ROOTB ││ DATA │
└────────────────┘║└───────────┘└───────────┘└───────────┘└───────────┘
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The following script prepares an attached USB flash drive for the swaproot mechanism.
PLEASE MAKE SURE THAT THIS IS THE ONLY USB DISK ATTACHED. THE DISK WILL BE FORMATTED!
target=/dev/sda
dd if=/dev/zero of=$target bs=1M count=10
parted --align optimal --script $target mklabel msdos
parted --align optimal --script $target mkpart primary 1MiB 1024MiB
parted --align optimal --script $target mkpart primary 1024MiB 5120MiB
parted --align optimal --script $target mkpart primary 5120MiB 9216MiB
parted --align optimal --script $target mkpart primary 9216MiB 100%
parted $target print
mkfs.ext4 -F -L STAGING -m 0 ${target}1
mkfs.ext4 -F -L ROOTA -m 0 ${target}2
mkfs.ext4 -F -L ROOTB -m 0 ${target}3
mkfs.ext4 -F -L DATA -m 0 ${target}4
test -d /media/staging || mkdir -p /media/staging
mount --label STAGING /media/staging/
cd /media/staging
which dump || apt-get install -y dump
dump -j9 -0af /media/staging/root.dump /
test -d /media/roota || mkdir -p /media/roota
mount --label ROOTA /media/roota/
cd /media/roota
restore -rf /media/staging/root.dump
test -d /media/rootb || mkdir -p /media/rootb
mount --label ROOTB /media/rootb/
cd /media/rootb
restore -rf /media/staging/root.dump
sed -i 's/^rootdev=.*/rootdev=LABEL=ROOTA/g' /boot/armbianEnv.txt
sync
rebootThe following scripts are part of the armbian swaproot mechanism:
Displays the device that is used for the active root filesystem.
Saves the currently booted root filesystem as dump.
Alternates the active root device between ROOTA and ROOTB labeled filesystems.
Restores the current backup of the root filesystem on the alternate root partition.