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)
16
The End
17
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Operating ReplicaSets

What would happen if we delete the ReplicaSet? As you might have guessed, both the ReplicaSet and everything it created (the Pods) would disappear with a single kubectl delete -f rs/go-demo-2.yml command. However, since ReplicaSets and Pods are loosely coupled objects with matching labels, we can remove one without deleting the other. We can, for example, remove the ReplicaSet we created while leaving the two Pods intact.

kubectl delete -f rs/go-demo-2.yml \
    --cascade=false  

We used the --cascade=false argument to prevent Kubernetes from removing all the downstream objects. As a result, we got the confirmation that replicaset "go-demo-2" was deleted. Let's confirm that it is indeed removed from the system.

kubectl get rs  

As expected, the output states that no resources were found.

If --cascade=false indeed prevents Kubernetes from removing...