Marc Boorshtein - Kubernetes – An Enterprise Guide: Effectively containerize applications, integrate enterprise systems, and scale applications in your enterprise, 2nd Edition

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Early Access Publication: Kubernetes An Enterprise Guide

Early Access Production Reference: B17950

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ISBN: 978-1-80323-003-0

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1. Chapter 1: Docker and Container Essentials
2. Chapter 2: Deploying Kubernetes Using KinD
3. Chapter 3: Kubernetes Bootcamp
4. Chapter 4: Services, Load Balancing, and External DNS
5. Chapter 5: Integrating Authentication into Your Cluster
6. Chapter 6: RBAC Policies and Auditing
7. Chapter 7: Deploying a Secured Kubernetes Dashboard
8. Chapter 8: Extending Security Using Open Policy Agent
9. Chapter 9: Node Security with Gatekeeper
10. Chapter 10: Auditing Using Falco and EFK
11. Chapter 11: Backing up Workloads
12. Chapter 12: Istio Deployment
13. Chapter 13: Building and Deploying Applications on Istio
14. Chapter 14: Provisioning a Platform

Before we begin, you may have read that Kubernetes will be deprecating Docker as a compatible runtime in an upcoming release. We will explain this change in more details in the next section, but for now, we will continue with the introduction to containers and the advantages that they deliver.

Containers are one of the most transformational technologies that we have seen in years. Technology companies, corporations, and end users have all adopted it to handle everyday workloads. Increasingly, common off-the-shelf (COTS) applications are transforming from traditional installations into fully containerized deployments. With such a large technology shift, it is essential for anyone in the Information Technology realm to learn about containers.

In this chapter, we will introduce the problems that containers address. After an introduction to why containers are important, we will introduce the runtime that launched the modern container frenzy, Docker and explain its relationship to Kubernetes. Well also cover how Kubernetes recent deprecation of support for Docker as a runtime impacts the use of Docker and why you should still be familiar with how to use it. By the end of this chapter, you will understand how to install Docker and how to use the most common Docker CLI commands.

In this chapter, we will cover the following topics:

• Understanding the need for containerization
• Kubernetes Deprecating Docker
• Understanding Docker
• Installing Docker
• Using the Docker CLI

Let's get started!

This chapter has the following technical requirements:

• An Ubuntu 18.04+ server with a minimum of 4 GB of RAM, though 8 GB is suggested
• You can access the code for this chapter by going to the following GitHub repository: https://github.com/PacktPublishing/Kubernetes-and-Docker-The-Complete-Guide.

You may have experienced a conversation like this at your office or school:

Developer: "Here's the new application. It went through weeks of testing and you are the first to get the new release."

.. A little while later .

User: "It's not working. When I click the submit button, it shows an error about a missing dependency."

Developer: "That's weird; it's working fine on my machine."

This is one of the most frustrating things a developer can encounter when delivering an application. Often, the issues that creep up are related to a library that the developer had on their machine, but it wasn't included in the distribution of the package. It may seem like an easy fix for this would be to include all the libraries alongside the release, but what if this release contains a newer library that overwrites the older version, which may be required for a different application?

Developers need to consider their new releases, as well as any potential conflicts with any existing software on the user's workstations. This often becomes a careful balancing act that requires larger deployment teams to test the application on different system configurations. It can also lead to additional rework for the developer or, in some extreme cases, full incompatibility with an existing application.

There have been various attempts to make application delivery easier over the years. First, there are solutions such as VMware's Thinapp, which virtualizes an application (not to be confused with virtualizing an operating system). It allows you to package the application and its dependencies into a single executable package. This packaging eliminates the issues of an application's dependencies conflicting with another application's dependencies since the application is in a self-contained package. This provided application isolation not only eliminates dependency issues but also provides an enhanced level of security and eases the burden of operating system migrations.