4

Reclaiming Docker Disc Space on OSX

 1 year ago
source link: https://fuzzyblog.io/blog/docker/2017/09/06/reclaiming-docker-disc-space-on-osx.html
Go to the source link to view the article. You can view the picture content, updated content and better typesetting reading experience. If the link is broken, please click the button below to view the snapshot at that time.

Reclaiming Docker Disc Space on OSX

Sep 6, 2017

A few nights ago, after a truly horrible night's sleep complete with my first ever incidence of acid reflux, I woke to find my Mac nattering at me about being out of disc space. And by out of disc space I mean that I was down to about 3 gigs out of a terabyte sized SSD. Yikes!

Taking a look at the normal culprits yielded no surprise increases and I can distinctly recall having in excess of 30 gigs just a day or two ago. Given all the server side problems with respect to Docker and disc space that I have written about previously, I had a strong hunch that somehow Docker was involved.

My first thought was that perhaps Docker logs are huge. On OSX, Docker logs are stored here:

~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/log

But a quick:

09:41 $ du -shc ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/log
 20K	/Users/sjohnson/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/log
 20K	total

Nope – clearly 20K isn't anything for disc space usage.

Containers

My next thought was that perhaps Docker has some massive backing store for containers. I did a bunch of searches and ran across this Docker thread and then another thread, both of which pointed me to the Docker.qcow2 file.

Here's what a du -shc showed me on this file:

du -shc     ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
 57G	/Users/sjohnson/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
 57G	total

Futile Attempts to Reclaim Space

I tried the normal things like:

docker system prune

And when that failed, I tried a bash based approach:

#!/bin/bash
for item in $(docker ps -aq); do
docker stop $item
docker rm $item
done

for item in $(docker images --filter dangling=true -q); do
docker rmi $item
done

But even after both of these, I still had:

du -shc     ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
 57G	total

My Solution

Here was the approach that I used:

  1. Quit Docker for Mac entirely.
  2. rm /Users/sjohnson/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
  3. As best as I can tell this is actually safe because containers can always be rebuilt.
  4. Restart Docker
  5. Verify space usage:

du -shc ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2 1.3G total

I then built a container and then reverified disc space usage.

du -shc     ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
1.3G	total

I then built some more containers and then checked disc space usage:

du -shc     ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
3.0G	total

I then started my overall "build all containers" shell script and tracked progress as it went:

du -shc     ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
3.0G	total

09:58 $ du -shc     ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
3.1G	total

du -shc     ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
3.4G    total

du -shc     ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
5.4G    total

By the time all containers were built:

du -shc     ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
7.2G    /Users/sjohnson/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2

And now, several days later and even more deploys, it has increased again:

du -shc     ~/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
8.2G	/Users/sjohnson/Library/Containers/com.docker.docker/Data/com.docker.driver.amd64-linux/Docker.qcow2
8.2G	total

Read More


About Joyk


Aggregate valuable and interesting links.
Joyk means Joy of geeK