Book Image

Mastering PowerCLI

By : Sajal Debnath
Book Image

Mastering PowerCLI

By: Sajal Debnath

Overview of this book

Have you ever wished that every morning you could automatically get a report with all the relevant information about your datacenter in exactly the same format you want? Or whether you could automate that boring, exhausting task? What if some crucial task needs to be performed on a regular basis without any error? PowerCLI scripts do all that and much more for VMware environments. It is built on top of the popular Windows PowerShell, with which you can automate server tasks and reduce manual input, allowing you to focus on more important tasks. This book will help you to achieve your goals by starting with a short refresher on PowerShell and PowerCLI and then covering the nuances of advanced functions and reusable scripts. Next you will learn how to build a vSphere-powered virtualized datacenter using PowerCLI while managing different aspects of the environment including automated installation, network, and storage. You will then manage different logical constructs of vSphere environment and different aspects of a virtual machine. Later, you will implement the best practices for a security implementation in vSphere Environment through PowerCLI before discovering how to manage other VMware environments such as SRM, vCloud Director and vCloud Air through PowerCLI. You will also learn to manage vSphere environments using advanced properties by accessing vSphere API and REST APIs through PowerCLI. Finally, you will build a Windows GUI application using PowerShell followed by a couple of sample scripts for reporting and managing vSphere environments with detailed explanations of the scripts. By the end of the book, you will have the required in-depth knowledge to master the art of PowerCLI scripting.
Table of Contents (21 chapters)
Mastering PowerCLI
Credits
Foreword
About the Author
Acknowledgment
About the Reviewers
www.PacktPub.com
Preface
Index

Automation through PowerShell scripts


From a programming perspective, there is not much difference between a scripting language and a more traditional programming language. You can make pretty complex programs with a scripting language.

The main difference between any traditional programming language and scripts is that in programming language, you can build compiled binary code, which can run as a standalone. In scripting, it cannot run as a standalone. A script depends on another program to execute it at runtime, or you can say that it requires another program to interpret it. Also, the code for the script is normally available for you to read. It is there in plain text form and at run time, it is executed line by line. In the case of a traditional programming language, you get a binary code which cannot be easily converted to the source code.

To summarize, if the runtime can see the code, then it is scripting language. If it is not then it was generated through a more traditional language.

Another more generic difference is that in typical scripting languages such as shell and PowerShell scripts, we use commands, which can be run directly from the command line and can give you the same result. So, in a script, we use those full high-level commands and bind them using basic programming structures (conditional logic, loops, and so on) to get a more sophisticated and complex result, whereas in traditional programming you use basic constructs and create your own program to solve a problem.

In PowerShell, the commands are called cmdlets, and we use these cmdlets and the basic constructs to get what we want to achieve. PowerShell cmdlets typically follow a verb-noun naming convention, where each cmdlet starts with a standard verb, hyphenated with a specific noun. For example, Get-Service, Stop-Service, and so on.

To write a PowerShell script, you can use any text editor, write the required code, and then save the file with a .ps1 extension. Next, from the PowerShell command line, run the script to get the desired result.