Book Image

The DevOps 2.3 Toolkit

By : Viktor Farcic
Book Image

The DevOps 2.3 Toolkit

By: Viktor Farcic

Overview of this book

Building on The DevOps 2.0 Toolkit, The DevOps 2.1 Toolkit: Docker Swarm, and The DevOps 2.2 Toolkit: Self-Sufficient Docker Clusters, Viktor Farcic brings his latest exploration of the DevOps Toolkit as he takes you on a journey to explore the features of Kubernetes. The DevOps 2.3 Toolkit: Kubernetes is a book in the series that helps you build a full DevOps Toolkit. This book in the series looks at Kubernetes, the tool designed to, among other roles, make it easier in the creation and deployment of highly available and fault-tolerant applications at scale, with zero downtime. Within this book, Viktor will cover a wide range of emerging topics, including what exactly Kubernetes is, how to use both first and third-party add-ons for projects, and how to get the skills to be able to call yourself a “Kubernetes ninja.” Work with Viktor and dive into the creation and exploration of Kubernetes with a series of hands-on guides.
Table of Contents (18 chapters)
The End
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Injecting configurations from key/value literals

Hopefully, even when our applications need different configs to work in distinct clusters, the differences are limited. Often, they should be limited to only a few key/value entries. In such cases, it might be easier to create ConfigMaps using --from-literal.

Let's take a look at an example:

kubectl create cm my-config \
    --from-literal=something=else \
kubectl get cm my-config -o yaml  

The output of the latter command is as follows (metadata is removed for brevity):

apiVersion: v1 
  something: else 
  weather: sunny 
kind: ConfigMap 

We can see that two entries were added, one for each literal.

Let's create a Pod with the ConfigMap mounted:

kubectl create -f cm/alpine.yml 
kubectl exec -it alpine -- \
    ls /etc/config 

The output of the latter command is as follows...