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unable to create netboot image


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Hi Folks,

I'm still learning Casper, so need your help. I'm trying to create a net boot image so that it can be uploaded at Net Boot server for Mac imaging.

I installed Mavericks OS X 10.9.5 on an external drive, did necessary customization so that the size of the net boot image can be reduced. After that, from another Mac (running on 10.9.5), I fired up System Image Utility, selected that external drive & tried to create net boot image. The wizard run & at step "Copying Source Volume" it gave below error

Image Creation failed - The operation couldn't be completed (system image utility error 2.)

Any help in this regard would be highly appreciated.

Best answer by davidacland

Looking on the Apple support pages it might be a mismatch issue with the OS versions.

Alternatively it could be a problem with the source or target drive.

Have you tried using @bentoms AutoCasperNBI? It's worked every time for me.

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  • Contributor
  • December 18, 2014

Hi Sidhu,

How did you install 10.9.5 on the external drive? From the install OS X application? If you installed from the combo update it will leave the recovery partition all messed up. Also, do you have enough free space on the Mac running SIU to save the image?


davidacland
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  • Valued Contributor
  • December 18, 2014

Looking on the Apple support pages it might be a mismatch issue with the OS versions.

Alternatively it could be a problem with the source or target drive.

Have you tried using @bentoms AutoCasperNBI? It's worked every time for me.


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Hi Carlos,

Many thanks for your response. Yes I did install 10.9.5 on external drive using combo update because I was under impression that both OS should be running on the same version. As now you are pointing out that combo update might have messed up with recovery partition, so what can be the solution in this case?

By the way, Mac has enough free space where SIU was running.

Looking forward for your support.


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Hi David,

Thanks for your response. I'll give it a shot at AutoCasperNBI & will feedback the results very soon.

Cheers


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Hi David,

One quick question though about AutoCasperNBI -

There is an option "Reduce Image Size" in this app & if selected, you would have 8GB net boot image (10.9.x) which I think it is too big in size. Although Ben mentioned that "NetBoot clients will only pull the data required to boot the OS" but I'm still concerned with the size of this net boot image because we have several locations/offices already suffering from network bandwidth issues & I don't want to add another one!

So what could be the best bet in this case?

Thanks


davidacland
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  • Valued Contributor
  • December 18, 2014

That sounds about right. I made a 10.10.1 nbi last week and it was 10.75GB.

Ben is correct, the client only pulls the files it needs so the size of the nbi shouldn't really matter.


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By any chance, do we know how much amount of data (in MBs/GBs) a Mac pulls from NetBoot server while loading this netboot image because I need to pass on this information to the network team.

May be I'm asking too much but if I get this information then it would be a great help.

Thanks


davidacland
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  • Valued Contributor
  • December 18, 2014

No idea I'm afraid. If I had to guess I would say 2-4GB although assuming you're imaging a Mac you'll be pulling down lots more data than that.


Forum|alt.badge.img+5
  • Contributor
  • December 18, 2014

Hi Sidhu,

What you want to do is a clean install on the external drive using the "Install OS X Mavericks.app", then you would do any updates and customization. From there boot from another OS X source and run SIU...what I would also recommend is renaming the Hard Drive you are making an image from to Netboot or something along those lines, sometimes having the image hdd and the hard drive you are running SIU from with the same name may also cause an issue.


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  • Contributor
  • December 18, 2014

I would use @bentoms AutoCasperNBI . Create a read-only DMG (in advanced options) then image the drive using disk utility.


bentoms
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  • Legendary Contributor
  • December 20, 2014

@sidhu_navdeep, I'm not sure how much data is pulled via an NBI when booted.. But if you use AutoCasperNBI & tick "reduce image" it removes some items from the NBI which would in turn lessen the nw load as things that aren't there cannot be loaded.

I'd advise testing with your NW people via NetBoot & make sure that they are happy with the generated traffic.

If they feel that too much is being pulled then, as per what @jpwade31 suggested, tick "Create A Read-Only DMG" then restore that to an external drive & boot off of that.

BUT, if when imaging your pulling an OS (8ish GB) & something like an Adobe Suite installer (6-12 GB).. Then that may raise concerns either way & in fact the NBI would be much less than the overall load.


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Thanks guys for the overwhelming response. Much appreciated.

I managed to create NetBoot image using AutoCasperNBI & size is 7.5GB. A big thanks to Ben for creating a wonderful app!

As far as imaging & its content is concerned, we are using WAN optimizer (Riverbed) to optimize WAN traffic. It caches all the data which passes through it & deliver to the machine like a LAN. However it is unable to optimize tftp traffic (UDP-69 port) which is being used by NetBoot process while delivering boot image to a Mac. That's why I was emphasizing more on the network traffic during booting process.

As Ben advised, NBI should be much less than the overall load, I'm going to test this in a test environment & will share my feedback.

Thanks again for all your help :-)

Cheers


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Hi again,

I've another question regarding configuration of NetBoot server. After uploading NetBoot image at NetBoot server, it is asking below information

"Subnets on which to listen for the NetBoot image. One of the subnets must include the IP address of the NetBoot server"

There are two fields i.e. Subnet & Netmask. Do I really need to populate these two fields to get this working or DHCP relays at network L3 devices should do the trick for me or do I need to leverage "Network Segments" section to populate NetBoot server for a subnet?

Please suggest. Thanks


daz_wallace
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Hi @sidhu_navdeep

It sounds like you're using the JAMF NetSUS appliance.

I've not got round to digging further but my understanding is that section is to do with the local firewall on the appliance and so is certainly required I'm afraid, in addition to passing the broadcast packets on.

If you're not too worried about the security, you could stick larger ranges in to cover your whole LAN.

Hope that helps!

Darren


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Hi Darren,

Thanks for your reply. Yes I'm using JAMF NetSUS appliance & I should have mentioned this in my earlier post. Sorry for that. Anyways I'm certainly concerned with the security & not in a position to publish the larger range.

So what I understood from your response is that apart from publishing local subnet & netmask detail (where NetBoot server resides), I can add a smaller subnet & netmask so that it can start replying to the broadcast packets. Is my understanding correct, please?


daz_wallace
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Hi @sidhu_navdeep

That matches with my understanding.

At minimum, you need to add:
- the IP address / range the netSUS is on (possibly just IP Address and 255.255.255.255)
- the the IP address / range your netboot clients are on.

Hope that helps!

Darren


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Thanks Darren. It indeed helped me a lot.

One last question - Do I need to configure "Network Segments" section to populate NetBoot server for a subnet in JSS or is this option really helpful if I have multiple NetBoot servers in the environment?


daz_wallace
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sorry @sidhu_navdeep for the lack of response over the holiday break! :)

It's the second one, and even then, thats only if you remotely / schedule kicking off a netboot of a client/s from Casper.

You can still override this by using 'Alt' during boot of the device.

Darren


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No worries Darren :-) Wishing you a very happy new year!

We don't have any plans/requirements to remotely/schedule kicking off a NetBoot of a client from Casper. So I think it's not mandatory to configure this option even if we are going to have multiple NetBoot servers. Is my understanding correct, please?

Navdeep


daz_wallace
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Hi Navdeep,

And a Happy New Year to you too!

Exactly, you don't have to configure it if you won't use multiple Netboot servers and / or remotely starting a netboot session.

Darren


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Sorry mate, I think there is a confusion. We will definitely have multiple NetBoot servers at a later stage however there won't be any requirement for starting a netboot session remotely. So please suggest the appropriate approach & configuration.

Many thanks

Navdeep


daz_wallace
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No worries.

That should also be fine. 

I meant if you only have one netboot server or if you don't care about remotely starting a Netboot then it doesn't matter.

Darren


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Thanks Darren for all your support. Much appreciated!


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  • New Contributor
  • January 4, 2015

hi @sidhu_navdeep

In regards to the size of your NBI created with AutoCasperNBI.

You can further reduce the size of the image by converting the image to a sparse image.

I have found that it reduces the NBI from aroun 7.5Gb to 4.5Gb. This is easier to push around to remote sites. As for how much data gets pulled down the line from the server to the client during netboot operations - this is not much of a concern for me. But getting that NBI out to our remote sites is and saving 3GB is worthwhile for us.

In my testing i have found no significant speed differences between the sparseimage and the original image. If anything the sparseimage actually seems to be a little bit faster to netboot.

I follow a similar method to how DeployStudio creates its NBI set

First step is to create a spare image from the original image

hdiutil convert -format UDSP /path/to/your/NBI/NetBoot.reduced.dmg -o /path/to/your/NBI/NetBoot.reduced.sparseimage.dmg

Second step is to remove (or move) the original image

rm /path/to/your/NBI/NetBoot.reduced.dmg

Third step is to now create a symlink to point any reference to the old NetBoot.reduced.dmg to our new sparse image

cd /path/to/your/NBI
ln -s NetBoot.reduced.dmg.sparseimage NetBoot.reduced.dmg

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Hi, thanks for your post.

I'm bit confused/concerned about 2nd & 3rd step where we are removing & creating a symlink. I'm not sure about the purpose of these steps. Are they really required to make this working?

By the way, I've created sparse image & now the size is reduced to 4.4 GB which looks good.
But please let me know whether my NetBoot server going to entertain this sparse image & will the clients boot from this sparse image?


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