Book Image

Getting Started with Containerization

By : Dr. Gabriel N. Schenker, Hideto Saito, Hui-Chuan Chloe Lee, Ke-Jou Carol Hsu
Book Image

Getting Started with Containerization

By: Dr. Gabriel N. Schenker, Hideto Saito, Hui-Chuan Chloe Lee, Ke-Jou Carol Hsu

Overview of this book

Kubernetes is an open source orchestration platform for managing containers in a cluster environment. This Learning Path introduces you to the world of containerization, in addition to providing you with an overview of Docker fundamentals. As you progress, you will be able to understand how Kubernetes works with containers. Starting with creating Kubernetes clusters and running applications with proper authentication and authorization, you'll learn how to create high-availability Kubernetes clusters on Amazon Web Services (AWS), and also learn how to use kubeconfig to manage different clusters. Whether it is learning about Docker containers and Docker Compose, or building a continuous delivery pipeline for your application, this Learning Path will equip you with all the right tools and techniques to get started with containerization. By the end of this Learning Path, you will have gained hands-on experience of working with Docker containers and orchestrators, including SwarmKit and Kubernetes. This Learning Path includes content from the following Packt products: • Kubernetes Cookbook - Second Edition by Hideto Saito, Hui-Chuan Chloe Lee, and Ke-Jou Carol Hsu • Learn Docker - Fundamentals of Docker 18.x by Gabriel N. Schenker

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Getting Started with Containerization
Dr. Gabriel N. Schenker | Hideto Saito | Hui-Chuan Chloe Lee | Ke-Jou Carol Hsu
Mar, 2019 | 12 hours 16 minutes
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Table of Contents (25 chapters)
Title Page
Title Page
Copyright
Copyright
About Packt
About Packt
Contributors
Contributors
Preface
Preface
Free Chapter
1
What Are Containers and Why Should I Use Them?
What Are Containers and Why Should I Use Them?
Technical requirements
What are containers?
Why are containers important?
What's the benefit for me or for my company?
The Moby project
Docker products
The container ecosystem
Container architecture
Summary
Questions
Further reading
2
Setting up a Working Environment
Setting up a Working Environment
Technical requirements
The Linux command shell
PowerShell for Windows
Using a package manager
Choosing a code editor
Docker Toolbox
Docker for Mac and Docker for Windows
Minikube
Summary
Questions
Further reading
3
Working with Containers
Working with Containers
Technical requirements
Running the first container
Starting, stopping, and removing containers
Inspecting containers
Exec into a running container
Attaching to a running container
Retrieving container logs
Anatomy of containers
Summary
Questions
Further reading
4
Creating and Managing Container Images
Creating and Managing Container Images
What are images?
Creating images
Sharing or shipping images
Summary
Questions
Further reading
5
Data Volumes and System Management
Data Volumes and System Management
Technical requirements
Creating and mounting data volumes
Sharing data between containers
Using host volumes
Defining volumes in images
Obtaining Docker system information
Listing resource consumption
Pruning unused resources
Consuming Docker system events
Summary
Questions
Further reading
6
Distributed Application Architecture
Distributed Application Architecture
What is a distributed application architecture?
Patterns and best practices
Running in production
Summary
Questions
Further reading
7
Single-Host Networking
Single-Host Networking
Technical requirements
The container network model
Network firewalling
The bridge network
The host network
The null network
Running in an existing network namespace
Port management
Summary
Questions
Further reading
8
Docker Compose
Docker Compose
Demystifying declarative versus imperative
Running a multi-service app
Scaling a service
Building and pushing an application
Summary
Questions
Further reading
9
Orchestrators
Orchestrators
What are orchestrators and why do we need them?
The tasks of an orchestrator
Overview of popular orchestrators
Summary
Questions
Further reading
10
Introduction to Docker Swarm
Introduction to Docker Swarm
Architecture
Swarm nodes
Stacks, services, and tasks
Multi-host networking
Creating a Docker Swarm
Deploying a first application
The swarm routing mesh
Summary
Questions
Further reading
11
Zero Downtime Deployments and Secrets
Zero Downtime Deployments and Secrets
Zero downtime deployment
Secrets
Summary
Questions
Further reading
12
Building Your Own Kubernetes Cluster
Building Your Own Kubernetes Cluster
Introduction
Exploring the Kubernetes architecture
Setting up the Kubernetes cluster on macOS by minikube
Setting up the Kubernetes cluster on Windows by minikube
Setting up the Kubernetes cluster on Linux via kubeadm
Setting up the Kubernetes cluster on Linux via Ansible (kubespray)
Running your first container in Kubernetes
13
Walking through Kubernetes Concepts
Walking through Kubernetes Concepts
Introduction
An overview of Kubernetes
Linking Pods and containers
Managing Pods with ReplicaSets 
Deployment API
Working with Services
Working with volumes
Working with Secrets
Working with names
Working with Namespaces
Working with labels and selectors
14
Playing with Containers
Playing with Containers
Introduction
Scaling your containers
Updating live containers
Forwarding container ports
Ensuring flexible usage of your containers
Submitting Jobs on Kubernetes
Working with configuration files
15
Building High-Availability Clusters
Building High-Availability Clusters
Introduction
Clustering etcd 
Building multiple masters
16
Building Continuous Delivery Pipelines
Building Continuous Delivery Pipelines
Introduction
Moving monolithic to microservices
Working with the private Docker registry
Integrating with Jenkins
17
Building Kubernetes on AWS
Building Kubernetes on AWS
Introduction
Playing with Amazon Web Services
Setting up Kubernetes with kops
Using AWS as Kubernetes Cloud Provider
Managing Kubernetes cluster on AWS by kops
18
Advanced Cluster Administration
Advanced Cluster Administration
Introduction
Advanced settings in kubeconfig
Setting resources in nodes
Playing with WebUI
Working with the RESTful API
Working with Kubernetes DNS
Authentication and authorization
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Index
Index

Demystifying declarative versus imperative

Docker Compose is a tool provided by Docker that is mainly used where one needs to run and orchestrate containers running on a single Docker host. This includes but is not limited to development, continuous integration (CI), automated testing, and manual QA.

Docker Compose uses files formatted in YAML as input. By default, Docker Compose expects these files to be called docker-compose.yml, but other names are possible. The content of a docker-compose.yml is said to be a declarative way of describing and running a containerized application potentially consisting of more than a single container.

So, what is the meaning of declarative?

First of all, declarative is the antonym of imperative. Well, that doesn't help much. Now that I have introduced another definition, I need to explain both of them:

  • Imperative: It's a way in which we can solve problems by specifying the exact procedure which has to be followed by the system.

If I tell a system such as the...

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