Table Of Content

Marko Lukša M A N N I N G Kubernetes resources covered in the book Resource (abbr.) [API version] Description Section Namespace* (ns) [v1] Enables organizing resources into non-overlapping 3.7 groups (for example, per tenant) Pod (po) [v1] The basic deployable unit containing one or more 3.1 processes in co-located containers ReplicaSet (rs) [apps/v1beta2**] Keeps one or more pod replicas running 4.3 s d ReplicationController (rc) [v1] The older, less-powerful equivalent of a 4.2 a o ReplicaSet kl or w Job [batch/v1] Runs pods that perform a completable task 4.5 g n yi CronJob [batch/v1beta1] Runs a scheduled job once or periodically 4.6 o pl e DaemonSet (ds) [apps/v1beta2**] Runs one pod replica per node (on all nodes or 4.4 D only on those matching a node selector) StatefulSet (sts) [apps/v1beta1**] Runs stateful pods with a stable identity 10.2 Deployment (deploy) [apps/v1beta1**] Declarative deployment and updates of pods 9.3 Service (svc) [v1] Exposes one or more pods at a single and stable 5.1 IP address and port pair s ce Endpoints (ep) [v1] Defines which pods (or other servers) are 5.2.1 ervi exposed through a service S Ingress (ing) [extensions/v1beta1] Exposes one or more services to external clients 5.4 through a single externally reachable IP address ConfigMap (cm) [v1] A key-value map for storing non-sensitive config 7.4 g nfi options for apps and exposing it to them o C Secret [v1] Like a ConfigMap, but for sensitive data 7.5 PersistentVolume* (pv) [v1] Points to persistent storage that can be mounted 6.5 into a pod through a PersistentVolumeClaim e g ora PersistentVolumeClaim (pvc) [v1] A request for and claim to a PersistentVolume 6.5 t S StorageClass* (sc) [storage.k8s.io/v1] Defines the type of dynamically-provisioned stor- 6.6 age claimable in a PersistentVolumeClaim * Cluster-level resource (not namespaced) ** Also in other API versions; listed version is the one used in this book (continues on inside back cover) Kubernetes in Action Kubernetes in Action MARKO LUKŠA MANNING SHELTER ISLAND For online information and ordering of this and other Manning books, please visit www.manning.com. The publisher offers discounts on this book when ordered in quantity. For more information, please contact Special Sales Department Manning Publications Co. 20 Baldwin Road PO Box 761 Shelter Island, NY 11964 Email: [email protected] ©2018 by Manning Publications Co. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by means electronic, mechanical, photocopying, or otherwise, without prior written permission of the publisher. Many of the designations used by manufacturers and sellers to distinguish their products are claimed as trademarks. Where those designations appear in the book, and Manning Publications was aware of a trademark claim, the designations have been printed in initial caps or all caps. Recognizing the importance of preserving what has been written, it is Manning’s policy to have the books we publish printed on acid-free paper, and we exert our best efforts to that end. Recognizing also our responsibility to conserve the resources of our planet, Manning books are printed on paper that is at least 15 percent recycled and processed without the use of elemental chlorine. Manning Publications Co. Development editor: Elesha Hyde 20 Baldwin Road Review editor: Aleksandar Dragosavljevic´ PO Box 761 Technical development editor: Jeanne Boyarsky Shelter Island, NY 11964 Project editor: Kevin Sullivan Copyeditor: Katie Petito Proofreader: Melody Dolab Technical proofreader: Antonio Magnaghi Illustrator: Chuck Larson Typesetter: Dennis Dalinnik Cover designer: Marija Tudor ISBN: 9781617293726 Printed in the United States of America 1 2 3 4 5 6 7 8 9 10 – EBM – 22 21 20 19 18 17 To my parents, who have always put their children’s needs above their own brief contents PART 1 OVERVIEW 1 ■ Introducing Kubernetes 1 2 ■ First steps with Docker and Kubernetes 25 PART 2 CORE CONCEPTS 3 ■ Pods: running containers in Kubernetes 55 4 ■ Replication and other controllers: deploying managed pods 84 5 ■ Services: enabling clients to discover and talk to pods 120 6 ■ Volumes: attaching disk storage to containers 159 7 ■ ConfigMaps and Secrets: configuring applications 191 8 ■ Accessing pod metadata and other resources from applications 225 9 ■ Deployments: updating applications declaratively 250 10 ■ StatefulSets: deploying replicated stateful applications 280 vii viii BRIEF CONTENTS PART 3 BEYOND THE BASICS 11 ■ Understanding Kubernetes internals 309 12 ■ Securing the Kubernetes API server 346 13 ■ Securing cluster nodes and the network 375 14 ■ Managing pods’ computational resources 404 15 ■ Automatic scaling of pods and cluster nodes 437 16 ■ Advanced scheduling 457 17 ■ Best practices for developing apps 477 18 ■ Extending Kubernetes 508