Learning CoreOS

Kingston Smiler. S, Shantanu Agrawal

• Publisher: Packt Publishing
• Year: 2016
• eBook ISBN: 9781785888304
• Edition: 1
• Topic: Computer Science
• Subtopic: System Administration
• Index: Computer Science

Your one-stop guide for building, configuring, maintaining, and deploying one of the world's fastest growing OSes

About This Book

• Understand the features of CoreOS and learn to administrate and secure a CoreOS environment
• Develop, test, and deploy cloud services and applications more quickly and efficiently inside lightweight containers using CoreOS
• This is a complete tutorial on CoreOS, which is the preferred OS for cloud computing as it contains components that facilitate cloud management

Who This Book Is For

This book is for cloud or enterprise administrators and application developers who would like to gain knowledge about CoreOS to deploy a cloud application or micro-services on a cluster of cloud servers. It is also aimed at administrators with basic networking experience. You do not need to have any knowledge of CoreOS.

What You Will Learn

• Understand the benefits of CoreOS as a cloud orchestration platform
• Learn about lightweight containers and various container frameworks such as Docker and RKT in CoreOS
• Manage services and containers across cluster using Fleet and systemd
• Set up a CoreOS environment using Vagrant
• Create and manage CoreOS clusters
• Discover the service parameters using etcd
• Find out about chaining services running on the cluster using Flannel / Rudder and Weave
• Create a virtual tenant network and service chaining using OVS

In Detail

CoreOS is an open source operating system developed upon the Linux kernel. The rise of CoreOS is directly related to the rise of Docker (a Linux container management system). It is a minimal operating system layer and takes a different approach to automating the deployment of containers. The major difference between CoreOS and other Linux distributions is that CoreOS was designed to deploy hundreds of servers. CoreOS immensely helps the users to create systems, which are easy to scale and manage, making life easier for all, be it developer, QA, or deployer.

This book is all about setting up, deploying, and using CoreOS to manage clusters and clouds. It will help you understand what CoreOS is and its benefits as a cloud orchestration platform. First, we'll show you how to set up a simple CoreOS instance with single node in the cluster and how to run a Docker container inside the CoreOS instance. Next, you'll be introduced to Fleet and systemd, and will deploy and distribute Docker services across different nodes in cluster using Fleet.

Later, you'll be briefed about running services in a cluster with constraints, publishing the services already running on the cluster to new services, and making your services interact with each other. We conclude by teaching you about advanced container networking. By the end of the book, you will know the salient features of CoreOS and will be able to deploy, administrate, and secure a CoreOS environment.

Style and approach

This practical guide covers the basics and advanced topics related to CoreOS and lightweight containers. The topics are covered in an easy-to-follow manner with each feature explained in detail, beginning with a brief overview and followed by an explanation of its corresponding configuration files.

Learning CoreOS

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Table of Contents

Learning CoreOS

Credits

About the Authors

About the Reviewer

www.PacktPub.com

eBooks, discount offers, and more

Why subscribe?

Preface

What this book covers

What you need for this book

Who this book is for

Conventions

Reader feedback

Customer support

Downloading the color images of this book

Errata

Piracy

Questions

1. CoreOS, Yet Another Linux Distro?

Introduction to CoreOS

CoreOS versus other Linux distributions

CoreOS high-level architecture

Service discovery

etcd

Container management

Linux Container

cgroups

Namespace

Chroot

Docker

Docker versus LXC

Rocket

CoreOS cluster management:

systemd

fleet

CoreOS and OpenStack

Summary

2. Setting Up Your CoreOS Environment

Installing GIT

Installing VirtualBox

Introduction to Vagrant

Installing Vagrant

Vagrant configuration files

Cloud-config

The config.rb configuration file

Starting a CoreOS VM using Vagrant

Setting up CoreOS on VMware vSphere

Installing VMware vSphere Client

Introduction to Docker

Image

Container

Volumes

Links

Installing Docker

Creating a sample Docker image using Docker File

Docker File

Pulling the Docker image from Docker Hub

Running Docker Image

Summary

3. Creating Your CoreOS Cluster and Managing the Cluster

Introduction to clustering

The why and the benefits of clustering

CoreOS clustering

Cluster discovery

Static discovery

etcd discovery

DNS discovery

systemd

Service unit files

Starting and stopping a service

fleet

Architectural overview

Engine

Agent

fleetctl

Standard (local) and global units

Unit file options for fleet

Instantiating the service unit in the cluster

Recovering from node failure

Summary

4. Managing Services with User-Defined Constraints

Introduction to service constraints

Predefined constraints using metadata

Service level affinity/anti-affinity

Node-level affinity

High availability

Summary

5. Discovering Services Running in a Cluster

Introduction and necessity of service discovery

Mechanism for service discovery

Operations of etcd

Operations using etcdctl

etcd write using etcdctl

etcd read using etcdctl

etcd watch using etcdctl

Example of etcd using etcdctl

Operations using cURL

etcd read using curl

etcd write using curl

etcd watch using curl

Example using curl

HAProxy and service discovery

Summary

6. Service Chaining and Networking Across Services

Introduction to and necessity of service chaining

Introduction to Docker networking

Container–Container communication

Docker0 bridge and veth pair

Using Link

Using common network stack

Container to CoreOS host communication

Host networking

docker0 bridge

Container to CoreOS outside world communication

Host networking

Port mapping

Container – Container communication in different CoreOS nodes

Introduction to Weave

Introduction to Flannel/Rudder

Installation

Setting up Weave

Container startup

Integrating Flannel with CoreOS

Summary

7. Creating a Virtual Tenant Network and Service Chaining Using OVS

Introduction to OVS

OVS architectural overview

Advantages of using OVS in CoreOS

Introduction to overlay and underlay networks

Introduction to network virtualization

OpenFlow support in OVS

OpenFlow switch

OpenFlow controller

OpenFlow channel

Running OVS in CoreOS

Attaching docker0 bridge to OVS

Configuration in CoreOS Instance 1

Configurations during the instantiation of a CoreOS node 1 in a cluster

Configurations during the creation of a container for CoreOS Instance 1

Configuration in CoreOS Instance 2

Configurations during the instantiation of CoreOS node 2 in a cluster

Configurations during the creation of a container for CoreOS Instance 2

Attaching container's veth interface to OVS

Configuration in CoreOS Instance 1

Configurations during the instantiation of a CoreOS node in a cluster

Configurations during the creation of the first container for a tenant

Configurations during the creation of subsequent containers for a tenant

Configuration in CoreOS Instance 2

Configurations during the instantiation of a CoreOS node in a cluster

Configurations during the creation of the first container for a tenant

Configurations during the creation of subsequent containers for a tenant

Looping issue

Summary

8. What Next?

Container security

Update and patches – CoreUpdate

Dex

sysdig

Competitive container orchestration mechanism

Kubernetes

Kubernetes master

Kubernetes nodes

Kubernetes pods

Kubernetes service

CoreOS and Kubernetes

Apache-Mesos

Mesos master

Mesos agent

ZooKeeper

Mesos frameworks

Swarm

Docker data volume management

Introduction to Flocker

Flocker control services

Flocker agents

Flocker plugin for Docker

Open Container Project

Summary

Index

Learning CoreOS

Copyright © 2016 Packt Publishing

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First publis...

Table of contents

• Learning CoreOS