如果在持续集成中使用Docker，如何使Docker不占用磁盘空间 [英] How can I make docker to not eat up disk space if used in Continuous integration

问题描述

我正在与docker一起玩，并计划在GitLab CI环境中使用它，以将当前项目状态打包到容器中，并提供运行中的实例进行审查。

I使用一个非常简单的Dockerfile如下：

  FROM php：7.0-apache 
 RUN sed -i's！/ var / www / html！/ var / www / html / public！g'/etc/apache2/sites-available/000-default.conf 
 COPY。 / var / www / html / 
  

现在，只要有一个新的（空）文件（ 触摸foobar ）到当前目录并调用

  docker build -t test2 -rm。 
  

再次，将创建一个包含所有代码的全新图层。

如果我不创建新文件，则旧图像似乎可以很好地重用。

我有一个半途而废的解决方案以下 Dockerfile ：

  FROM test2：latest 
 RUN sed -i's！/ var / www / html！/ var / www / html / public！g'
  

/etc/apache2/sites-available/000-default.conf
COPY。 / var / www / html /

深入研究该问题并将存储驱动程序切换为 overlay ，这似乎正是我想要的-仅添加了几个字节新的层。没有。

是否有更好的解决方案？

解决方案

一个建议是使用命令 docker image prune 清理悬空的图像。这样可以节省很多空间。您可以在CI中定期运行此命令。

I am playing with docker and plan to use it in a GitLab CI environment to package the current project state to containers and provide running instances to do reviews.

I use a very simple Dockerfile as follows:

FROM php:7.0-apache
RUN  sed -i 's!/var/www/html!/var/www/html/public!g' /etc/apache2/sites-available/000-default.conf
COPY . /var/www/html/

Now, as soon as a I a new (empty) file (touch foobar) to the current directory and call

docker build -t test2 --rm .

again, a full new layer is created, containing all of the code.

If I do not create a new file, the old image seems to be nicely reused.

I have a half-way solution using the following Dockerfile:

FROM test2:latest
RUN  sed -i 's!/var/www/html!/var/www/html/public!g' 

/etc/apache2/sites-available/000-default.conf COPY . /var/www/html/

After digging into that issue and switching the storage driver to overlay, this seems to be what I want - only a few bytes are added as a new layer.

But now I am wondering, how I could integrate this into my CI setup - basically I would need two different Dockerfiles - depending on whether the image already exists or it doesn't.

Is there a better solution for this?

解决方案

One suggestion is to use the command docker image prune to clean dangling images. This can save you a lot of space. You can run this command regularly in your CI.

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