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Docker image disk usage tool
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#!/bin/env sh | |
# imagesize.sh calculates the on disk size of images by pulling | |
# and comparing inode and block usage. Requires using a fresh | |
# device to accurately measure the difference caused by each | |
# image. This is intended to measure the on disk size caused | |
# by pulling an image with docker rather than the sum of all | |
# the file usage just inside the docker graph driver directory. | |
# | |
# Usage: | |
# sh imagesize.sh <device> <storage driver> [<image>, ...] | |
# | |
# How to use: | |
# $ fallocate -l 18GB testvolume | |
# $ device=$(sudo losetup -f --show ./testvolume) | |
# $ sudo mkfs.ext4 -F $device | |
# $ sudo sh imagesize.sh $device overlay ubuntu:latest golang:latest | |
tmpdir=$(mktemp -d) | |
device=$1 | |
graphdriver=$2 | |
shift | |
shift | |
mount $device $tmpdir | |
echo "Mounted $device to $tmpdir" | |
echo "Starting docker engine using $graphdriver storage driver" | |
docker daemon -D -s $graphdriver -g $tmpdir > /tmp/dockertestlog.txt 2>&1 & | |
sleep 10 | |
base=$(df --output=used $tmpdir | tail -n 1) | |
basei=$(df --output=iused $tmpdir | tail -n 1) | |
function usage_diff() { | |
usage=$(df --output=used $tmpdir | tail -n 1) | |
usagei=$(df --output=iused $tmpdir | tail -n 1) | |
diff=$(expr $usage - $base) | |
diffi=$(expr $usagei - $basei) | |
base=$usage | |
basei=$usagei | |
echo "Size($1): $diff" | |
echo "Inodes($1): $diffi" | |
} | |
for image in "$@"; do | |
echo "Pulling $image" | |
docker pull $image | |
usage_diff $image | |
done | |
kill $(cat /var/run/docker.pid) | |
sleep 2 | |
umount $tmpdir | |
rmdir $tmpdir | |
echo "Unmounted and remove $tmpdir" |
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