DevOps: Puppet, Docker, and Kubernetes

Building images without using cached layers

By default, when we build an image, Docker will try to use the cached layers so that it takes less time to build. However, at times it is necessary to build from scratch. For example, you will need to force a system update such as yum -y update. Let's see how we can do that in this recipe.

Getting ready

Get a Dockerfile to build the image.

How to do it…

1. While building the image, pass the --no-cache option as follows:

   $ docker build -t test --no-cache - < Dockerfile
   

How it works…

The --no-cache option will discard any cached layer and build one Dockerfile by following the instructions.

There's more…

Sometimes, we also want to discard the cache after only a few instructions. In such cases, we can add any arbitrary ...