Book Image

The Kubernetes Bible

By : Nassim Kebbani, Piotr Tylenda, Russ McKendrick
4 (3)
Book Image

The Kubernetes Bible

4 (3)
By: Nassim Kebbani, Piotr Tylenda, Russ McKendrick

Overview of this book

With its broad adoption across various industries, Kubernetes is helping engineers with the orchestration and automation of container deployments on a large scale, making it the leading container orchestration system and the most popular choice for running containerized applications. This Kubernetes book starts with an introduction to Kubernetes and containerization, covering the setup of your local development environment and the roles of the most important Kubernetes components. Along with covering the core concepts necessary to make the most of your infrastructure, this book will also help you get acquainted with the fundamentals of Kubernetes. As you advance, you'll learn how to manage Kubernetes clusters on cloud platforms, such as Amazon Web Services (AWS), Microsoft Azure, and Google Cloud Platform (GCP), and develop and deploy real-world applications in Kubernetes using practical examples. Additionally, you'll get to grips with managing microservices along with best practices. By the end of this book, you'll be equipped with battle-tested knowledge of advanced Kubernetes topics, such as scheduling of Pods and managing incoming traffic to the cluster, and be ready to work with Kubernetes on cloud platforms.
Table of Contents (28 chapters)
1
Section 1: Introducing Kubernetes
5
Section 2: Diving into Kubernetes Core Concepts
12
Section 3: Using Managed Pods with Controllers
17
Section 4: Deploying Kubernetes on the Cloud
21
Section 5: Advanced Kubernetes

Launching your first Cronjob

To close this first chapter on Pods, I suggest that we discover another new Kubernetes resource called Cronjob.

What are Cronjobs?

The name Cronjob can mean two different things and it is important to not get confused:

  • The UNIX cron feature
  • The Kubernetes Cronjob resource

Historically, Cronjobs are command scheduled using the cron UNIX feature, which is the most robust way to schedule the execution of a command in UNIX systems. This idea was later taken up in Kubernetes.

In Kubernetes, you are not going to schedule the execution of a command but the execution of a Pod. You can do that using the Cronjob resource.

Be careful because even though the two ideas are similar, they don't work the same at all. On UNIX and other derived systems such as UNIX, you schedule commands by editing a file called Crontab, which is usually found in /etc/crontab. In the world of Kubernetes, things are different: you are not going to schedule...