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    Mastering SaltStack
    Mastering SaltStack
    Mastering SaltStack
    Ebook699 pages4 hours

    Mastering SaltStack

    By Hall Joseph

    ()

    Read preview

    About this ebook

    Take charge of SaltStack to automate and configure enterprise-grade environments

    About This Book
    • Automate tasks effectively, so that your infrastructure can run itself
    • Take advantage of cloud-based services that can expand the capabilities of your own data centers
    • Tackle real-world problems that appear in everyday situations
    In Detail

    SaltStack is known as a popular configuration management system, but that barely scratches the surface. It is, in fact, a powerful automation suite, which is designed not only to help you manage your servers, but to help them manage themselves. SaltStack is used worldwide by organizations ranging from just a few servers, to tens of thousands of nodes across data centers in multiple continents. This award-winning software is fast becoming the standard for systems management in the cloud world.

    This book will take you through the advanced features of SaltStack, bringing forward capabilities that will help you excel in the management of your servers.

    You will be taken through the the mind of the modern systems engineer, and discover how they use Salt to manage their infrastructures, and why those design decisions are so important. The inner workings of Salt will be explored, so that as you advance your knowledge of Salt, you will be able to swim with the current, rather than against it.

    Various subsystems of Salt are explained in detail, including Salt SSH, Salt Cloud, and external pillars, filesystems, and job caches.

    You will be taken through an in-depth discussion of how to effectively scale Salt to manage thousands of machines, and how to troubleshoot issues when things don't go exactly the way you expect them to.

    You will also be taken through an overview of RAET, Salt's new transport protocol, and given an insight into how this technology improves Salt, and the possibilities that it brings with it.

    What You Will Learn
    • Learn how the pros are managing their infrastructures, and what techniques they use to keep everything running smoothly with Salt
    • Understand what makes Salt tick, and how that affects the way you use it
    • Take a look at familiar features in a new light, so that you have a better handle on how to approach tasks
    • Use Salt SSH to manage servers that don't fit Salt's traditional use cases
    • Besides automating your configuration, you will be able to automate your servers, and make them behave more intelligently
    • Make better use of cloud-based services, including compute clouds such as EC2, Azure and Openstack
    • Learn about the new RAET protocol, and how it changes the way automation works
    Who This Book Is For

    This book is ideal for professionals who have been managing groups of servers, and want to learn how to add functionality and expand their tool set. This book will also explain some of the more advanced features of Salt, and explore how to use them to bring additional power to the fundamentals that the professionals have already been using.

    Style and approach

    This book speaks informally, sometimes almost conversationally, to the user. Topics are covered in detail, using examples that should be comfortable to most users.

    LanguageEnglish
    PublisherPackt Publishing
    Release dateAug 19, 2015
    ISBN9781785288388
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      Book preview

      Mastering SaltStack - Hall Joseph

      Table of Contents

      Mastering SaltStack

      Credits

      Foreword

      About the Author

      About the Reviewers

      www.PacktPub.com

      Support files, eBooks, discount offers, and more

      Why subscribe?

      Free access for Packt account holders

      Preface

      What this book covers

      What you need for this book

      Who this book is for

      Conventions

      Reader feedback

      Customer support

      Errata

      Piracy

      Questions

      1. Reviewing a Few Essentials

      Executing commands remotely

      Master and Minions

      Targeting Minions

      Glob

      Perl Compatible Regular Expression (PCRE)

      List

      Subnet

      Grain

      Grain PCRE

      Pillar

      Compound

      Nodegroup

      Using module functions

      test.ping

      test.echo

      test.sleep

      test.version

      pkg.install

      pkg.remove

      file.replace

      Other file functions

      Various user and group functions

      sys.doc

      SLS file trees

      SLS files

      Tying things together with top files

      Organizing the SLS directories

      Using States for configuration management

      Using include blocks

      Ordering with requisites

      require

      watch

      onchanges

      onfail

      use

      prereq

      Inverting requisites

      Extending SLS files

      The basics of Grains, Pillars, and templates

      Using Grains for Minion-specific data

      Centralizing variables with Pillars

      Managing files dynamically with templates

      A quick Jinja primer

      Summary

      2. Diving into Salt Internals

      Understanding the Salt configuration

      Following the configuration tree

      Looking inside /etc/salt/

      Managing Salt keys

      Exploring the SLS directories

      Examining the Salt cache

      The Master job cache

      The Master-side Minion cache

      The external file server cache

      The Minion-side proc/ directory

      External modules

      The Renderer

      Rendering SLS files

      Render pipes

      Serving templated files

      Understanding the Loader

      Dynamic modules

      Execution modules

      Cloud modules

      Plunging into the State compiler

      Imperative versus declarative

      Requisites

      High and Low States

      High States

      Low States

      Enforcing statefulness

      name

      result

      changes

      comment

      Summary

      3. Exploring Salt SSH

      Grappling with SSH

      Remote shells

      Using rosters

      The flat roster

      host

      port

      user

      passwd

      sudo

      priv

      timeout

      thin_dir

      Other built-in rosters

      scan

      cache

      cloud

      ansible

      Building dynamic rosters

      Using Salt SSH

      Using a Saltfile

      Salt versus Salt SSH

      Architecture

      Performance

      Understanding the salt-thin agent

      Building the thin package

      Including extra modules

      Deploying the thin package

      Executing the thin package

      The Salt SSH shim

      Preparing for Salt States

      Running Salt

      Salt's running data

      Using the raw SSH mode

      Caching SSH connections

      Summary

      4. Managing Tasks Asynchronously

      Looking at the event system

      Reviewing the basics

      The structure of event data

      Watching event data

      Installing the event listener

      Using the event listener

      Firing custom data

      Namespacing events

      Namespacing guidelines

      Some common events

      salt/auth

      salt/key

      salt/minion//start

      salt/job//new

      salt/job//ret/

      salt/presence/present

      salt/presence/change

      Common cloud events

      salt/cloud//creating

      salt/cloud//requesting

      salt/cloud//querying

      salt/cloud//waiting_for_ssh

      salt/cloud//deploying

      salt/cloud//created

      salt/cloud//destroying

      salt/cloud//destroyed

      Salt API events

      salt/netapi/

      Building Reactors

      Configuring Reactors

      Writing Reactors

      Calling execution modules

      Calling runner modules

      Calling wheel modules

      Writing more complex Reactors

      Sending out alerts

      Using webhooks

      Reactors calling Reactors

      Using the queue system

      Learning how queues work

      Adding to the queue

      Listing queues

      Listing items in a queue

      Processing queue items

      Deleting items from a queue

      Using queues with the Reactor

      Spreading out State runs

      Dividing tasks among Minions

      Summary

      5. Taking Salt Cloud to the Next Level

      Examining the Salt Cloud configuration

      Global configurations

      The provider and profile configuration

      Providers

      Profiles

      Extending configuration blocks

      Building custom deploy scripts

      Understanding the Salt Bootstrap script

      Installing from prebuilt packages

      Installing from Git

      Looking back at legacy deploy scripts

      Writing your own deploy scripts

      Passing arguments to scripts

      Using file maps

      Taking a look at cloud maps

      Working with autoscale Reactors

      The cloud cache

      Using cloud cache events

      Setting up a schedule

      Catching cloud cache events

      Summary

      6. Using Salt with REST

      Looking at Salt's HTTP library

      Why a Salt-specific library?

      Using the http.query function

      GET versus POST

      Decoding return data

      Using the http.query state

      Using http.query with Reactors

      Understanding Salt API

      What is Salt API?

      Setting up Salt API

      CherryPy

      Tornado

      WSGI

      Creating SSL certificates

      Configuring authentication

      The external authentication module

      Taking your first steps with Salt API

      Issuing one-off commands

      Working with webhooks

      Security considerations

      More complex authentication

      Summary

      7. Understanding the RAET Protocol

      Comparing RAET and ZeroMQ

      Starting with HTTP

      SSH, the old favorite

      Using ZeroMQ

      ZeroMQ and security

      The need for RAET

      Flow-based programming

      The pieces of the puzzle

      Black boxes

      Shared storage

      Concurrent scheduling

      Driving with RAET

      Configuring RAET

      The RAET architecture

      The basics

      The RAET scheduler

      Estates and yards

      Summary

      8. Strategies for Scaling

      All about syndication

      Different folks, different strokes

      No need for micro-managing

      Configuring syndication

      High availability with multiple Masters

      Built-in high availability configuration

      Old-school high availability

      The round robin DNS

      IP-based load balancing

      Synchronizing files

      Base configuration files

      Synchronizing the nonexternal files

      Using rsync

      Using the event Reactor

      Incorporating external data sources

      The external job cache

      Using Returners on the Minions

      Using the Master job cache

      External filesystems

      GitFS

      base

      root

      mountpoint

      user and password

      insecure_auth

      pubkey, privkey, and passphrase

      Other source control backends

      SVNFS

      root and mountpoint

      trunk

      branches

      tags

      HGFS

      S3FS

      One environment per bucket

      Multiple environments per bucket

      AzureFS

      External Pillars

      cmd_yaml/cmd_json

      git

      redis

      mysql

      Using the Master API

      The Salt keys

      Configuration

      The file and Pillar roots

      Using the Wheel Reactor

      Testing load in the infrastructure

      Using the Minion Swarm

      Swarm internals

      Summary

      9. Monitoring with Salt

      Monitoring basics

      Establishing a baseline

      Reading the system vitals in Salt

      status.loadavg

      status.cpustats

      status.meminfo

      status.vmstats

      disk.usage, status.diskusage

      status.w

      status.all_status, status.custom

      Monitoring with Returners

      Deciding on a Returner

      Using monitoring states

      Defining a monitoring state

      Monitoring with web calls

      Working with beacons

      Monitoring file changes

      Beacon intervals

      Setting up alerts

      Alerting in State files

      Alerting from beacons

      Watching file changes

      Monitoring bad logins

      Summary

      10. Exploring Best Practices

      Future-proofing your infrastructure

      Setting up your directories

      Standard directory locations

      .sls versus init.sls

      Shallow versus deep

      Subdividing further

      The SLS efficiency

      Includes and extends

      Using includes

      Using extends

      Using templates to simplify SLS files

      Working with loops

      Decisions, decisions

      Using the built-in States

      Naming conventions

      Generic names

      Explicit names

      Templates and variables

      Nested variables

      Referring to variables in templates

      Summary

      11. Troubleshooting Problems

      What the…?

      Addressing the problem source

      Where is the trouble?

      The Master to Minion communication

      The network and CPU congestion

      Checking the Minion load

      Querying the Salt job data

      Using debug and trace modes

      info

      warn

      error

      debug/trace

      Running services in debug mode

      Using salt-call locally

      Working with YAML

      YAML basics

      dict

      list

      YAML idiosyncrasies

      Spacing

      Numbers

      Booleans

      List items

      Troubleshooting YAML

      Asking the community for help

      The salt-users mailing list

      Asking questions

      The Salt issue tracker

      Researching before posting

      Formatting your issues

      Requesting features

      #salt on IRC

      Final community thoughts

      Summary

      Index

      Mastering SaltStack

      Mastering SaltStack

      Copyright © 2015 Packt Publishing

      All rights reserved. No part of this book may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, without the prior written permission of the publisher, except in the case of brief quotations embedded in critical articles or reviews.

      Every effort has been made in the preparation of this book to ensure the accuracy of the information presented. However, the information contained in this book is sold without warranty, either express or implied. Neither the author nor Packt Publishing, and its dealers and distributors will be held liable for any damages caused or alleged to be caused directly or indirectly by this book.

      Packt Publishing has endeavored to provide trademark information about all of the companies and products mentioned in this book by the appropriate use of capitals. However, Packt Publishing cannot guarantee the accuracy of this information.

      First published: August 2015

      Production reference: 1130815

      Published by Packt Publishing Ltd.

      Livery Place

      35 Livery Street

      Birmingham B3 2PB, UK.

      ISBN 978-1-78528-216-4

      www.packtpub.com

      Credits

      Author

      Joseph Hall

      Reviewers

      Pedro Algarvio

      Darrel Clute

      JiWei Liu

      Hoàng Đình Quân

      Peng Yao

      Commissioning Editor

      Kartikey Pandey

      Acquisition Editor

      Vivek Anantharaman

      Content Development Editor

      Merwyn Dsouza

      Technical Editor

      Siddhesh Patil

      Copy Editors

      Relin Hedly

      Sonia Mathur

      Project Coordinator

      Neha Bhatnagar

      Proofreader

      Safis Editing

      Indexer

      Monica Mehta

      Graphics

      Disha Haria

      Production Coordinator

      Nilesh R. Mohite

      Cover Work

      Nilesh R. Mohite

      Foreword

      This is the Salt book I have been wanting to see for a long time. As the creator of Salt, I feel that many people don't know about the advanced and powerful capabilities of the Salt platform. Diving into the parts of Salt less trodden is where the truly amazing value of Salt comes into play. The more powerful aspects of Salt, such as how to use the Reactor for dynamic intelligent management, how to use salt-ssh to manage a wide variety of situations, and how to take Salt to the next level, are revealed in this book in an easy-to-understand way. I hope that this book will be a great help in bringing the great power of Salt to more people.

      Joseph Hall is likely the best person to write this book. He is not only a close friend, but has also been involved with the Salt project from the very beginning, including the early design of the Salt States system. Joseph is the second person to write code for Salt (apart from me). He was the first engineer hired by SaltStack.

      Thomas S. Hatch

      Founder and CTO, SaltStack

      About the Author

      Joseph Hall has touched just about every area of the modern technology world from his beginnings as a support technician to being a web programmer, QA engineer, systems administrator, Linux instructor, and cloud engineer. He is currently a senior cloud and integrations engineer at SaltStack. Joseph enjoys working with some of the best minds in the business with his coworkers and SaltStack's partners. He is also a classically trained chef. Joseph's supreme pleasure lies in working with what he calls computational gastronomy.

      I would like to thank my wife, Nat, for her support when I stayed up every night to write this book. I would also like to thank Tom Hatch for writing Salt and having the guts to turn it into the best company that I've ever worked for. My sincere thanks go out to Colton Meyers for hooking me up with Packt Publishing. I would also like to thank the Salt community for being awesome and helping make Salt what it is today.

      About the Reviewers

      Pedro Algarvio was a Sound Technician until May 2015. He likes to keep himself busy. Therefore, Pedro set out to make computers work for him. In his endeavor to deepen his knowledge of computers, he started with shell scripting and then moved on to learn Perl, and finally settled with Python. Pedro was involved with several open source projects. However, he credits Salt for giving him the opportunity to learn the most. He joined SaltStack in May 2015 and dedicated his time to improve the Salt software.

      I would like to thank my wife for her continuous friendship, love, and support throughout. She even supported me when I took the risk of quitting my job to to pursue a skill, in which I had no experience. I would also like to thank my twins for allowing me some spare time to review Joseph's book. Further, I want to thank the Salt community for teaching me new things everyday. Last but not least, I would like to thank God.

      I love learning new things. SaltStack gave the opportunity to learn more about Salt, which made me grow as a Python coder and enthusiast. I would like to thank SaltStack for their continuous belief and encouragement to the point of inviting me to join the team.

      Darrel Clute is an IT infrastructure architect. Throughout his career, he has predominately focused on network engineering. Darrel has also spent an equal amount of time focusing on systems engineering, primarily with Unix-based systems. Apart from his job, he is also an advocate of the open source software. This is used in enterprise as well as for individuals. Darrel will never advocate the use of open source purely for the sake of it.

      Outside his core competencies, he also has extensive experience with proprietary and open source virtualization platforms. His knowledge and experience with IaaS solutions—such as OpenStack—is constantly increasing as well. Additionally, with his systems engineering experience, Darrel has been exposed to and has supported various web and enterprise applications. His most recent exposure has been to PaaS solutions. This has led him to advocate that a public or private cloud offering is not complete without coupling IaaS and PaaS solutions designed and deployed in lockstep.

      Beyond his core infrastructure, Darrel has recently been developing programing skills to augment his daily activities. Throughout his career, he has utilized various languages and utilities to automate infrastructure. Some of Darrel's programming has been with the use of Bash, net-snmp, sed, awk, and holistically Python.

      JiWei Liu graduated in 2011. He is employed as a cloud computing and operation and maintenance engineer at Gamewave Group Limited (PRC), China's largest web game provider. It is also the leader of the Chinese web game industry and the professional provider of interactive entertainment services.

      I would like to thank my sweetheart for her help and support in the process of writing this book.

      Hoàng Đình Quân is a junior system administrator and network infrastructure engineer. He has extensive experience in designing, deploying, hardening, and maintaining Linux systems and the network infrastructure for small-and medium-sized companies.

      Peng Yao is an operations engineer with more than 8 years of experience in infrastructure automation, data visualization, and cloud computing. He is the founder and coordinator of the China SaltStack user group.

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      Preface

      I'm very excited to have been given the chance to put this book together. From an idea in the brain of Tom Hatch to an award-winning open source project to the flagship product of an award-winning open source company, I've been given the rare opportunity to watch Salt grow. Salt has become an incredibly powerful framework, which I wish I had access to years ago.

      Everyday, I learn something new about Salt. This book is a collection of a number of these things, which is aimed at the advanced user. Don't see it as the last word on any of the topics it covers. Instead, see it as a guide to using this tool to its fullest potential on your journey.

      As you read through this book, I hope that the ideas and examples in it inspire you to update and innovate your infrastructure.

      What this book covers

      Chapter 1, Reviewing a Few Essentials, talks about how to review a few fundamental concepts to get into the right frame of mind. While many of the concepts should be familiar to the experienced user, you are likely to find plenty of new information as well.

      Chapter 2, Diving into Salt Internals, jumps into the deeper workings behind Salt. It discusses the internal configuration, the loader system, renderers, and the state compiler.

      Chapter 3, Exploring Salt SSH, explores how Salt SSH is a powerful tool. It's been getting a lot of love from the core developers lately. This is possibly the most complete discussion of Salt SSH.

      Chapter 4, Managing Tasks Asynchronously, discusses how one of the most important concepts behind Salt is asynchronicity. This chapter lays down the fundamentals that will be referenced throughout the rest of the book.

      Chapter 5, Taking Salt Cloud to the Next Level, goes deeper, exposing parts of Salt Cloud, which turn casual users into experts. No matter how much you've used Salt Cloud, there's a good chance you've only scratched the surface.

      Chapter 6, Using Salt with REST, talks about how it's almost impossible to work with technology these days without depending on REST services. It uses Salt to tie these services to your infrastructure with ease.

      Chapter 7, Understanding the RAET Protocol, teaches you the concepts behind RAET and how they impact upon you. RAET is still new, but it's already found its way into large organizations.

      Chapter 8, Strategies for Scaling, talks about how to never assume that your infrastructure will stay small. It makes you think about how to scale your infrastructure properly before it's too late.

      Chapter 9, Monitoring with Salt, discovers how Salt is a powerful monitoring tool if you know how to use it. It tells you how to integrate it with existing tools or use Salt alone.

      Chapter 10, Exploring Best Practices, discusses the good and bad ways to use any tool. It teaches you the good ways to use Salt.

      Chapter 11, Troubleshooting Problems, tells you where to look and how to find help when things go wrong.

      What you need for this book

      To follow the examples in this book, you should be running at least version 2015.5 of Salt. Only one machine is strictly necessary because both the salt-master and the salt-minion service can be run together, but Linux is currently required to run the salt-master service.

      The examples in this book are targeted at Ubuntu Linux, except where stated otherwise.

      Who this book is for

      This book is ideal for professionals who have been managing groups of servers and want to learn how to add functionality and expand their toolset. This book explains some of the more advanced features of Salt. It explores how to use them to bring additional power to the fundamentals that the professionals have already been using.

      Conventions

      In this book, you will find a number of text styles that distinguish between different kinds of information. Here are some examples of these styles and an explanation of their meaning.

      Code words in text, database table names, folder names, filenames, file extensions, pathnames, dummy URLs, user input, and Twitter handles are shown as follows: This function does little more than the test.ping command.

      A block of code is set as follows:

      nodegroups:

        webdev: 'I@role:web,G@cluster:dev'

        webqa: 'I@role:web,G@cluster:qa'

        webprod: 'I@role:web,G@cluster:prod'

      Any command-line input or output is written as follows:

      # salt -S 192.168.0.0/24 test.ping

      New terms and important words are shown in bold. Words that you see on the screen, for example, in menus or dialog boxes, appear in the text like this: Click the Join This Group link and you will be subscribed.

      Note

      Warnings or important notes appear in a box like this.

      Tip

      Tips and tricks appear like this.

      Reader feedback

      Feedback from our readers is always welcome. Let us know what you think about this book—what you liked or disliked. Reader feedback is important for us as it helps us develop titles that you will really get the most out of.

      To send us general feedback, simply e-mail <[email protected]>, and mention the book's title in the subject of your message.

      If there is a topic that you have expertise in and you are interested in either writing or contributing to a book, see our author guide at www.packtpub.com/authors.

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      Chapter 1. Reviewing a Few Essentials

      Salt is a very powerful automation framework. Before we delve into the more advanced topics that this book covers, it may be wise to go back and review a few essentials. In this chapter, we will cover the following topics:

      Using remote execution

      Basic SLS file tree structure

      Using States for configuration management

      Basics of Grains, Pillars, and templates

      This book assumes that you already have root access on a device with a common distribution of Linux installed. The machine used in the examples in this book is running Ubuntu 14.04, unless stated otherwise. Most examples should run on other major distributions, such as recent versions of Fedora, RHEL 5/6/7, or Arch Linux.

      Executing commands remotely

      The underlying architecture of Salt is based on the idea of executing commands remotely. This is not a new concept; all networking is designed around some aspect of remote execution. This could be as simple as asking a remote Web server to display a static Web page, or as complex as using a shell session to interactively issue commands against a remote server.

      Under the hood, Salt is an example of one of the more complex types of remote execution. But whereas most Internet users are used to interacting with only one server at a time (so far as they are aware), Salt is designed to allow users to explicitly target and issue commands to multiple machines directly.

      Master and Minions

      Salt is based around the idea of a Master, which controls one or more Minions. Commands are normally issued from the Master to a target group of Minions, which then execute the tasks specified in the commands and then return any resulting data back to the Master.

      Targeting Minions

      The first facet of the salt command is targeting. A target must be specified with each execution, which matches one or more Minions. By default, the type of target is a glob, which is the style of pattern matching used by many command shells. Other types of targeting are also available, by adding a flag. For instance, to target a group of machines inside a particular subnet, the -S option is used:

      # salt -S 192.168.0.0/24 test.ping

      The following are most of the available target

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