现象

Step 3 : RUN pip install -r requirements.txt---> Running in fe0b84217ad1Collecting blinker==1.3 (from -r requirements.txt (line 1))Retrying (Retry(total=4, connect=None, read=None, redirect=None)) after connection broken by 'ProtocolError('Connection aborted.

解决方法

本质上是dns服务导致，尝试了很多种办法，发现下面的方法最好用：

docker build --network=host -t image_name .