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
Table of Contents (25 chapters)
Title Page
About Packt

Working with labels and selectors

Labelsare a set of key/value pairs, which are attached to object metadata. We could use labels to select, organize, and group objects, such as Pods, ReplicaSets, and Services. Labels are not necessarily unique. Objects could carry the same set of labels.

Label selectors are used to query objects with labels of the following types:

  • Equality-based:
    • Use equal (= or ==) or not-equal (!=) operators
  • Set-based:
    • Use in or notin operators

Getting ready

Before you get to setting labels in the objects, you should consider the valid naming convention of key and value.

A valid key should follow these rules:

  • A name with an optional prefix, separated by a slash.
  • A prefix must be a DNS subdomain, separated by dots, no longer than 253 characters.
  • A name must be less than 63 characters with the combination of [a-z0-9A-Z] and dashes, underscores, and dots. Note that symbols are illegal if put at the beginning and the end.

A valid value should follow the following rules:

  • A name must be...