You're reading from The Ultimate Docker Container Book Build, test, ship, and run containers with Docker and Kubernetes

Product type Paperback

Published in Aug 2023

Publisher Packt

ISBN-13 9781804613986

Length 626 pages

Edition 3rd Edition

Tools

Docker

Concepts

DevOps

Author (1):

Dr. Gabriel N. Schenker

View More author details

Table of Contents (26) Chapters

Preface

1. Part 1:Introduction

2. Chapter 1: What Are Containers and Why Should I Use Them? FREE CHAPTER

3. Chapter 2: Setting Up a Working Environment

4. Part 2:Containerization Fundamentals

5. Chapter 3: Mastering Containers

6. Chapter 4: Creating and Managing Container Images

7. Chapter 5: Data Volumes and Configuration

8. Chapter 6: Debugging Code Running in Containers

9. Chapter 7: Testing Applications Running in Containers

10. Chapter 8: Increasing Productivity with Docker Tips and Tricks

11. Part 3:Orchestration Fundamentals

12. Chapter 9: Learning about Distributed Application Architecture

13. Chapter 10: Using Single-Host Networking

14. Chapter 11: Managing Containers with Docker Compose

15. Chapter 12: Shipping Logs and Monitoring Containers

16. Chapter 13: Introducing Container Orchestration

17. Chapter 14: Introducing Docker Swarm

18. Chapter 15: Deploying and Running a Distributed Application on Docker Swarm

19. Part 4:Docker, Kubernetes, and the Cloud

20. Chapter 16: Introducing Kubernetes

21. Chapter 17: Deploying, Updating, and Securing an Application with Kubernetes

22. Chapter 18: Running a Containerized Application in the Cloud

23. Chapter 19: Monitoring and Troubleshooting an Application Running in Production

24. Index

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Introduction to pods

Contrary to what is possible in Docker Swarm, you cannot run containers directly in a Kubernetes cluster. In a Kubernetes cluster, you can only run pods. Pods are the atomic units of Deployment in Kubernetes. A pod is an abstraction of one or many co-located containers that share the same kernel namespaces, such as the network namespace. No equivalent exists in Docker SwarmKit. The fact that more than one container can be co-located and shared with the same network namespace is a very powerful concept. The following diagram illustrates two pods:

Figure 16.11 – Kubernetes pods

In the preceding diagram, we have two pods, Pod 1 and Pod 2. The first pod contains two containers, while the second one only contains a single container. Each pod gets an IP address assigned by Kubernetes that is unique in the whole Kubernetes cluster. In our case, these are the following IP addresses: 10.0.12.3 and 10.0.12.5. Both are part of a private...