---

layout: post
title: docker clear up for mac
categories: docker
description: bash shell docker clear up for mac

keywords: docker

1、Main

清理mac上Docker占用的磁盘空间

1.1、内容：

Docker依赖Linux系统的cgroup实现，在mac系统中运行的时候，Docker会启动一个虚拟机中的Linux内核，并在硬盘上放一个 qcow2 格式的磁盘镜像文件。这个文件会随着Docker的使用不断膨胀，即使删除不用的Docker Image和Container也不会缩小。我在测试完一个自动化工具的Dockerfile改写之后，Docker.qcow2文件就达到42GB了。  
  
Google搜了一圏发现一个叫Théo Chamley的法国人写了一个脚本释放Docker.qcow2文件占用的空间。基本原理是用 docker save 命令保存要保留的image，然后关闭Docker，删除Docker.qcow2，再启动Docker，它会自动重建，最后用 docker load 命令恢复保留的image。  

命令行

 sudo sh docker-clean.sh $(docker images | awk 'NR>1 {print $1":"$2}')  

脚本

#!/bin/bash  
# sudo sh docker-clean.sh $(docker images | awk 'NR>1 {print $1":"$2}')  
  
IMAGES=$@  
  
echo "This will remove all your current containers and images except for:"  
echo ${IMAGES}  
read -p "Are you sure? [yes/NO] " -n 1 -r  
echo    # (optional) move to a new line  
if [[ ! $REPLY =~ ^[Yy]$ ]]  
then  
    exit 1  
fi  
  
  
TMP_DIR=$(mktemp -d)  
  
pushd $TMP_DIR >/dev/null  
  
open -a Docker  
echo "=> Saving the specified images"  
for image in ${IMAGES}; do  
	echo "==> Saving ${image}"  
	tar=$(echo -n ${image} | base64)  
	docker save -o ${tar}.tar ${image}  
	echo "==> Done."  
done  
  
echo "=> Cleaning up"  
echo -n "==> Quiting Docker"  
osascript -e 'quit app "Docker"'  
while docker info >/dev/null 2>&1; do  
	echo -n "."  
	sleep 1  
done;  
echo ""  
  
echo "==> Removing Docker.qcow2 file"  
rm ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2  
  
echo "==> Launching Docker"  
open -a Docker  
echo -n "==> Waiting for Docker to start"  
until docker info >/dev/null 2>&1; do  
	echo -n "."  
	sleep 1  
done;  
echo ""  
  
echo "=> Done."  
  
echo "=> Loading saved images"  
for image in ${IMAGES}; do  
	echo "==> Loading ${image}"  
	tar=$(echo -n ${image} | base64)  
	docker load -q -i ${tar}.tar || exit 1  
	echo "==> Done."  
done  
  
popd >/dev/null  
rm -r ${TMP_DIR}  

貌似更好

• This patch fixes a bug which would prevent the online compaction from being enabled. Hopefully now it’s possible to turn it on again. I installed this version and then enabled experimental compaction by running the following script:
  

#!/bin/bash  
  
cd ~/Library/Containers/com.docker.docker/Data/database/  
git checkout master  
git reset --hard  
mkdir -p com.docker.driver.amd64-linux/disk  
echo 262144 > com.docker.driver.amd64-linux/disk/compact-after  
echo 262144 > com.docker.driver.amd64-linux/disk/keep-erased  
echo -n true > com.docker.driver.amd64-linux/disk/trim  
#echo -n 'tcp:9090' > com.docker.driver.amd64-linux/disk/stats  
git add com.docker.driver.amd64-linux/disk/compact-after  
git add com.docker.driver.amd64-linux/disk/keep-erased  
git add com.docker.driver.amd64-linux/disk/trim  
#git add com.docker.driver.amd64-linux/disk/stats  
git commit -s -m 'Enable on-line compaction'  

• I then rebooted the app. I created a large temporary file in a container, deleted it, and around 15 minutes later an fstrim /var was triggered from cron and the file became smaller again. (It’s also possible to trigger fstrim immediately with a command like docker run –rm –net=host –pid=host –privileged -it justincormack/nsenter1 /sbin/fstrim /var)

• In 17.07 (the upcoming edge release) I’m hoping to switch online compaction on by default. In 17.08 I’m hoping to automatically trigger fstrim when docker images are removed, instead of waiting for a cron job.