Anthias Deployment

If you do regular deployments you can create an image. A reasonable approach is to:

  • Shrink the last partition
  • Zero fill the remaining free space
  • Find the end of the last partition
  • DD that to a file
  • Use raspi-config to resize after deploying

Or you can use PiShrink to script all that.


chmod +x
sudo mv /usr/local/bin


# Capture and shrink the image
sudo dd if=/dev/mmcblk0 of=anthias-raw.img bs=1M
sudo anthias-raw.img anthias.img

# Copy to a new card
sudo dd if=anthias.img of=/dev/mmcblk0 bs=1M

If you need to modify the image after creating it you can mount it via loop-back.

sudo losetup --find --partscan anthias.img
sudo mount /dev/loop0p2 /mnt/

# After you've made changes

sudo umount /mnt
sudo losetup --detach-all

Manual Steps

If you have access to a graphical desktop environment, use GParted. It will resize the filesystem and partitions for you quite easily.

# Mount the image via loopback and open it with GParted
sudo losetup --find --partscan anthias-raw.img

# Grab the right side of the last partition with your mouse and 
# drag it as far to the left as you can, apply and exit
sudo gparted /dev/loop0

Now you need to find the last sector and truncate the file after that location. Since the truncate utility operates on bytes, you convert sectors to bytes with multiplication.

# Find the End of the last partition. In the below example, it's Sector *9812664*
$ sudo fdisk -lu /dev/loop0

Units: sectors of 1 * 512 = 512 bytes

Device       Boot  Start     End Sectors  Size Id Type
/dev/loop0p1        8192  532479  524288  256M  c W95 FAT32 (LBA)
/dev/loop0p2      532480 9812664 9280185  4.4G 83 Linux

sudo losetup --detach-all

sudo truncate --size=$[(9812664+1)*512] anthias-raw.img

Very Manual Steps

If you don’t have a GUI, you can do it with a combination of commands.

# Mount the image via loopback
sudo losetup --find --partscan anthias-raw.img

# Check and resize the file system
sudo e2fsck -f /dev/loop0p2
sudo resize2fs -M /dev/loop0p2

... The filesystem on /dev/loop0p2 is now 1149741 (4k) blocks long

# Now you can find the end of the resized filesystem by:

# Finding the number of sectors.
#     Bytes = Num of blocks * block size
#     Number of sectors = Bytes / sector size
echo $[(1149741*4096)/512]

# Finding the start sector (532480 in the example below)
sudo fdisk -lu /dev/loop0

Device       Boot  Start      End  Sectors  Size Id Type
/dev/loop0p1        8192   532479   524288  256M  c W95 FAT32 (LBA)
/dev/loop0p2      532480 31116287 30583808 14.6G 83 Linux

# Adding the number of sectors to the start sector. Add 1 because you want to end AFTER the end sector
echo $[532480 + 9197928 + 1]

# And resize the part to that end sector (ignore the warnings)
sudo parted resizepart 2 9730409 

Great! Now you can follow the remainder of the GParted steps to find the new last sector and truncate the file.

Extra Credit

It’s handy to compress the image. xz is pretty good for this

xz anthias-raw.img

xzcat anthias-raw.img | sudo dd of=/dev/mmcblk0

In these procedures, we make a copy of the SD card before we do anything. Another strategy is to resize the SD card directly, and then use dd and read in X number of sectors rather than read it all in and then truncate it. A bit faster, if a but less recoverable from in the event of a mistake.

Last modified June 23, 2023: Added deployment (c0af4b9)