如何使用缓存快速重建dockerfile？ [英] How to rebuild dockerfile quick by using cache?

问题描述

我想优化我的Dockerfile。我希望将缓存文件保留在磁盘中。
但是，我发现当我运行 docker build时。它总是尝试从网络中获取每个文件。

I want to optimize my Dockerfile. And I wish to keep cache file in disk. But, I found when I run docker build . It always try to get every file from network.

我希望在构建期间共享我的缓存目录（例如/ var / cache / yum / x86_64 / 6）。
但是，它仅在 docker run -v ... 上起作用。

I wish to share My cached directory during build (eg. /var/cache/yum/x86_64/6). But, it works only on docker run -v ....

有任何建议吗？（在此示例中，仅安装了1 rpm，在实际情况下，我需要安装数百rpm）

Any suggestion?(In this example, only 1 rpm installed, in real case, I require to install hundreds rpms)

我的Dockerfile草案

My draft Dockerfile

FROM centos:6.4
RUN yum update -y
RUN yum install -y openssh-server
RUN sed -i -e 's:keepcache=0:keepcache=1:' /etc/yum.conf
VOLUME ["/var/cache/yum/x86_64/6"] 
EXPOSE 22

第二次，我想构建类似的图像

At second time, I want to build a similar image

FROM centos:6.4
RUN yum update -y
RUN yum install -y openssh-server vim

我不希望再次从internat获取openssh-server（这很慢）。在我的真实情况下，它不是一个软件包，而是大约100个软件包。

I don't want the fetch openssh-server from internat again(It is slow). In my real case, it is not one package, it is about 100 packages.

推荐答案

对先前答案的更新，当前docker 构建
接受-build- arg 传递环境变量，例如 http_proxy
而不将其保存在生成​​的图像中。

An update to previous answers, current docker build accepts --build-arg that pass environment variables like http_proxy without saving it in the resulting image.

示例：

# get squid
docker run --name squid -d --restart=always \
  --publish 3128:3128 \
  --volume /var/spool/squid3 \
  sameersbn/squid:3.3.8-11

# optionally in another terminal run tail on logs
docker exec -it squid tail -f /var/log/squid3/access.log

# get squid ip to use in docker build
SQUID_IP=$(docker inspect --format '{{ .NetworkSettings.IPAddress }}' squid)

# build your instance
docker build --build-arg http_proxy=http://$SQUID_IP:3128 .

这篇关于如何使用缓存快速重建dockerfile？的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！