WHY Series #2
Late last week I got the following email via my contact form. It seemed like the ideal topic for the next post in the series. (Thanks Matt for the message!)
I have a question for your WHY series. I was debating with a co-worker yesterday why you would use the "Build and Capture" task sequence for OSD instead of capturing a system that you already have or have built with another method. I have a few ideas on advantages and disadvantages, but I would like to hear your opinion.
I am going to make a couple of assumptions based on what I read in the question. I interpret “a system that you already have” to mean an existing physical machine that would be captured to create an image. This might not be what the reader intended, but it should be addressed in this post regardless. Best practice is to create a hardware independent image on a virtual machine. (Need to address reasons why for that one in a future post.) I also see the phrase “built with another method”…which I interpret to be essentially a manually built image (as opposed to one using a B&C task sequence).
At the core, those are your options for image creation…automated with a Build & Capture task sequence or build it manually. A slight variation is to use the “Pause task sequence” step in an MDT task sequence to perform a step that can’t be automated…essentially automate all of it except for this one step.
Factors Impacting the Image Creation Process
When looking at the question of whether to manually build the image or use a Build and Capture task sequence, there are several key components that should be considered:
- Image updates. Don’t consider an image to be “golden”…think of it as “current”. This can be a key distinction. Gold implies that it will never change. Current deals with the reality that an image is going to need to be updated. (Let’s not even get into the Thick/Thin/Hybrid image scenario…that’s a discussion for another day…perhaps another “WHY” post.) With that said, unless you are the most hardcore of “thin image” proponents, your image will at least have the OS and updates. Which means that within a month of image creation (Patch Tuesday), the image will be missing necessary updates. How often do you update it? Remember, anything that isn’t in your image has to be installed after the image is laid down…which adds time. I know of a very major company (if you live in the US, you have their products in your home) that had not updated their XP image in several years. The post image update process took a couple of hours to deploy somewhere around 200 updates that were not included in the image. Application updates/upgrades are also part of this equation. Basic gist is that images MUST be updated…ideally on a regular basis.
- If applications are included in the image, are the applications packaged and able to be installed silently? If so, then that process can be automated. If not, then it has to be a manual step. Same goes for image tweaks.
- Ideally you would like to use the same processes for managing apps and updates that go in your image that you use for managing the existing systems in your environment. You already have a “Patch Tuesday” process. Use the same process when building the image. You already have a process for pushing out application upgrades/updates. Use the same process in your image build.
- In the end, you MUST have consistent repeatable results. You need a process that produces a reliable image every single time.
- Lastly, you are busy. I’ve never met an IT person who had too much time on their hands. You need this process to take as little time out of your day/week as possible.
With those factors in mind…lets run them through the grid of our methods for image creation and see how things shake out.
Build and Capture Image Creation Process:
If your core applications that will go in the image can be installed silently…and if you are using either WSUS or SCCM for deploying updates, then this is the ideal situation. Your B&C task sequence could be as simple as “Click Next” and come back later to see your shiny new WIM file. Once you’ve got it working (which I won’t deny could be challenging) it couldn’t be any easier. Once it is going, you will never look back. I know of at least one company that has a recurring Task Sequence deployment to a virtual machine…to create a new image the day after Patch Tuesday each month. Completely automated. Score!
Because the task sequence is automated, there is very little time involved. Just click next and check on it later. Because all of the tasks are automated, there isn’t any room for admin error. Because it is automated, you are more likely to update your image on a regular basis. The process IS standardized and repeatable. Oh…and if a step does have to be performed manually, use an MDT task sequence with the “Pause” step to automate as much as possible…and only do the non-automatable tasks manually.
Manual Image Creation:
Manual is…well…manual. You install the OS from DVD/ISO. You install each app. You apply all the updates. You run Sysprep. You capture the image. All manually. Hopefully you are following a checklist. Hopefully you don’t forget a step. Good luck with that.
The manual image creation process is characterized by the following:
- Slow. All those manual steps take time.
- Time consuming. Because it is slow, realistically, you will not update the image as often as you should.
- Open for admin error (i.e. forgetting a step or installing a component slightly differently upon image rebuild)
- Not standardized/repeatable
Overall…friends don’t let friends use a manual image creation process. You might wish it on your enemies though! ;-) However…see my conclusion below for one instance where you might use an existing image.
If you’ve followed my blog for long or have seen my presentations at MMS or TechEd, then you should have known I was going to land on the side of using the Build and Capture Task Sequence before you even started this article. In my opinion (that I think I’ve adequately backed up with solid logic), using a B&C task sequence to create your image is the only way to go. It just makes sense from a time/automation/repeatability/manageability standpoint.
The ONLY exception that I see to this is if you are migrating from an old technology (i.e. Ghost) to SCCM, AND you are migrating from XP to Windows 7 / Windows 8. In that instance…would I recommend going through the process of recreating all of your Windows XP images…that you are going to be getting rid of soon anyway? No. In that instance I would say go ahead and capture that existing image (or if it is already a WIM file…see if you can deploy it as-is). Don’t spend the time recreating the image that you are going to be dumping (since XP EOL is coming up very soon!).
Would love your comments and feedback. Keep the ideas for future posts coming!
Until next time…keep asking the right questions.