The PowerShell language was developed to provide engineers with a method to quickly automate the provisioning and management of environments. In the last decade, PowerShell's use has greatly expanded, to encompass the setup and configuration of a myriad of hardware and software systems. Since third-party manufacturers are creating PowerShell modules to control their systems, PowerShell is becoming the automation language of choice. It is being used to configure multiple systems from multiple manufacturers, with a single set of PowerShell code.
Creating scripts for enterprise environments requires a robust scripting framework. A scripting framework consists of reusable code that you can leverage for a large majority of your scripts. This framework needs to be efficient, reliable, and secure. It must also provide logging capabilities, leverage answer files, and be flexible for execution on a wide variety of systems.
As you are exploring this book, you will learn a large number of tested and industry-proven scripting techniques. The examples you create will be applied at the end of the book in a Windows server scanning script. This will enable you to quickly integrate new sections of code into your own scripts, and will provide a trusted platform you can confidently deploy in your environment.
In this chapter, you will:
Learn about the Windows server scanning script created throughout this book
Explore performance optimizations implemented throughout each chapter
Review different components you should include in all of your PowerShell scripts
There can be times in large enterprises where you need to determine the functionality of systems. If you don't have large asset management software, you will need the ability to perform a discovery. This book was designed to provide a significant jumpstart for the creation of a Windows server scanning script. The script takes into consideration the limitations of Windows components and provides extremely detailed information about systems.
Some of the items that you will be scanning for include:
Windows processes: You will identify the Windows processes on the system to determine what processes are running with alternate user credentials. This will help identify systems that have service accounts for process execution.
Windows services: You will review the Windows services on the system to discover what services are not running as built-in accounts. This will further identify service account usage in your enterprise.
This script is designed to provide a robust platform to scan your enterprise. Variations of this script have been used in multiple Fortune 500 companies and executed on well over 10,000 systems. The chapters in this book have been designed to enable you to quickly learn the core components to integrate this PowerShell tool into your personal repository.
This book dives into important performance considerations for your scripts. Since PowerShell is an extremely flexible language, you can complete the same activity in multiple ways. While both sets of code get the script to create the same results, there are ways to optimize your code to make it much more efficient. This becomes increasingly important as you evaluate large amounts of data.
Execution time for file scanning, for example, exponentially grows with the quantity of files and the file sizes. 100 files with 100 lines of code can quickly create 10,000 evaluations. Now, if you scale that to 6 million files in a storage volume times 100 lines of code, you are performing 600 million evaluations. Small code performance improvements can significantly optimize your scanning of scripts at scale.
Some of the performance considerations include:
Regular expressions over arrays: Regular expressions can be difficult to learn, but they provide significant performance improvements to your scripts. You will learn how to properly implement dynamic regular expressions in your scripts.
As you develop different scripts for your enterprise environment, you will have a core set of functions that you tend to use in all of your scripts. Some enterprise scripters create their own functions, while others leverage scripts from the vast community of PowerShell developers. With either method, you will need a solid foundation to build your scripts on.
Some of the most common items this book provides for scripting templates include:
Encryption and decryption technologies: Probably the most common requirement in enterprise environments is security. It's no secret that you should not have clear text administrative-level credentials in scripts. Providing an encryption and decryption function in your scripts is essential to maintaining a secure enterprise.
Logging mechanisms: The second most common requirement in enterprise environments is logging script actions. Since scripts are typically executed on a large number of systems at the same time, you will need the ability to track exactly what is being performed on these systems. Creating a logging function will provide the ability to log script actions to both the event log and a log file.
Answer file logic: One of the more advanced methods for PowerShell scripting is leveraging an answer file for script variables. The core to the answer file is that you can add, remove, and modify the values in the answer file without having to modify your script. This provides the ability to have flexibility in your scripts without needing to touch any lines of code.
Standardized comment blocks: When you are creating scripts, it's essential to give yourself and others reminders of what the script's function is. Comment blocks enable the ability to provide details about the script, revision history, and execution parameters of the script.
Whether you are new to PowerShell scripting or you have been scripting for a long time, this book provides thought-inspiring methods to improve your scripting abilities. As you work through this book, it's strongly encouraged to incorporate these examples in your own scripts. This applied learning methodology will significantly help in your retention of the content, and provide a very robust enterprise scripting platform.
In this chapter, you explored the different components that will be implemented in the Windows server scanning script. You continued to learn about the different performance optimizations that you will be implementing in the book. Finally, you reviewed the individual components that should be included in most of your PowerShell Scripts.
In the next chapter, you will begin your journey by learning script structure, comment blocks, and script logging techniques.