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

Applying VMFS resignaturing


Since we are talking about managing storage in vSphere environments in this chapter, I felt we should cover one extra topic here. One of the common tasks in vSphere is VMFS resignature. First, let's try to find out what a VMFS resignaturing task is.

By default, ESXi mounts all the datastores that are visible to the host. Each datastore has a unique UUID that is stored in the datastore superblock. Also, the unique LUN ID is store in the VMFS metadata. When a LUN is replicated, all the information is copied block by block and we get an identical LUN. If the original datastore had an UUID as X, the copied LUN also has an UUID as X.

Consider the case when you want to mount the replicated LUN; ESXi will see a duplicate LUN and will not mount the LUN automatically.

To mount the replicated LUN, we can either force-mount the copy in case we are sure the original is not in use, or we can resignature the copy so that it will have another UUID.

Though there are other ways of...