MacbookAir6,2 Netboot NilObjectException Imaging Errors

[nethers]

We're experiencing NilObjectException Errors while imaging our MacbookAir6,2's using ThunderBolt to Ethernet from our 10.8.4 NetBoot Image. Is there any sufficient documentation to fix this on the 8.72 JSS. It's almost 50/50 as to when it occurs, I can image get the error then re-image and not get the error.

It's then about 50/50 as to whether it will be able to recon and enroll itself properly. We've also seen a less common IOException Error. We've had to manually delete the JAMF Keychain in the Library/App Support/JAMF folder to get these machines to enroll. We're not sure if they're going to pose additional errors in the future.

We thought it may have been a bad NBI so we built a second one, and same occurrence.

[mvest20]

I was having the same issue, though not with MacBook Airs, but with white MacBooks. I followed the instructions in this article (http://www.macos.utah.edu/documentation/administration/setup_netboot_service_on_mac_os_x_10.6.x_client.x_client/setup_netboot_service_on_mac_os_x_10.6.x_client-diskless_netboot.html ) to modify the netboot image and that has resolved the issue. Here's another JAMFNation article that deals with the same issue.

For the record, I know that the utah.edu article deals with 10.6, but I also have a 10.8.4 netboot image, and this resolved the issue for me. I was getting both the NilObjectException and IOException errors.

Hope that helps.

[emikesell]

Look at this kb from apple, it fixed my errors.

http://support.apple.com/kb/TS4316

[nethers · Accepted solution]

After calling JAMF Support, they walked me through a solution that involved mounting the NBI and adding a folder /etc/ with a replacement rc.netboot file. Then all my issues disappeared. Seems like they should script that to check for that as part of JAMF, even if it is a system image utility issue.

[mking529]

Just out of curiosity, was the replacement rc.netboot the one from the macos.utah.edu site? We've got some new computers that require a Mountain Lion NetBoot and I'm experiencing this issue as well. Just wondering. :)

[mvest20]

Sorry to drag this old post up again, but I am about to set up a Mavericks netboot environment. Does anyone know if the rc.netboot file still needs to be modified, and if so, does the same file work in the Mavericks environment?

[nessts]

I am using something similar to the utah.edu solution in 10.9 copied the rc.netboot straight into the new 10.9 NBI and it works fine.

[mvest20]

That's great news. Did you by any chance attempt to set up the 10.9 environment without the modified rc.netboot file?

[jhalvorson]

I assumed the need for swapping the rc.netboot file to use a RAM disk for the shadow file was because diskless mode wasn't alway being honored when hosting the net boot images on 10.7/10.8 with Server. I found using the RAM disk based rc.netboot really helped the constancy for our imaging team.

This past weekend, I upgraded three of our net boot servers to 10.9 with Server 3.0.1. Then created new 10.9 and 10.8.5 net boot images. First tests proved that I still need to increase the size of the .dmg file to avoid the startup disk is almost full error. So far, none of the config centers have indicated problems with diskless not working, so I haven't had to switch them to use RAM disk (replace the rc.netboot) file yet. As more systems net boot and they report that they can't dismount or erase the internal drive, then I'll swap out the rc.netboot to force the use of the RAM disk.

NetBoot Error: Startup Disk is Almost Full
https://jamfnation.jamfsoftware.com/article.html?id=198

[nessts]

yes it worked fine, but would not do diskless.

[CasperSally]

I was having the same NilObjectException errors only on our Air6,2 models with a 10.8 netboot set. On that set I had manually made the changes suggested on the utah site.

To try to avoid the errors for that model Air, I built a new netboot (10.9.3) and inserted the rc.netboot from the utah site (I did have to rename it so it wasn't .sh).

It seemed ok in testing, but on one of our larger configs of 76 packages, like the last 10 or so packages were missing (but casper imaging showed no errors). If I image the same machine with the same config using the 10.8 netboot set - all packages came down fine - so the packages and config are ok.

Strange. Never seen it before where packages just didn't come down with no error thrown off in casper imaging. I guess I'm going to go back to standard rc.netboot and manually try manually making suggested changes on 10.9 set.

[CasperSally]

the 'untitled' drive that mounts on the desktop on my 10.9 NBI - free space goes from 256MB down to zero & that's when weird stuff happens - only on larger non compiled images like 75% through imaging process.

Same config (and now same rc.netboot file) on 10.8 NBI - that 'untitled' drive free space stays consistently over 100MB and packages all come down fine.

Wonder what could cause that in 10.9 netboot set, anyone have ideas?

[foigus]

I've built a custom diskless Mavericks utility/repair NBI (i.e. not a Casper NetBoot image) with AutoDMG+System Image Utility and run into a situation where the free space on the NBI dmg itself was the limiting factor. Even if the University of Utah RAM Disk workaround was properly implemented and claimed, for example, there was 2GB of scratch space. Since the NBI dmg itself only claimed to have a couple hundred megabytes free OS X considered the disk to be nearly full. I could trace this back to Apple's IconServices aggressively caching icons (since my NBI was never booted) and filling up the NBI's startup disk--I could single user boot, run "df" every few seconds and watch the startup disk fill to capacity.

This resulted in various failures, depending on how much free space was left and how quickly I attempted to log in:
- NetBoot failing completely due to the inability for OS X to build a mount point for the AFP (i.e. non-University of Utah) scratch space
- The error "Unapproved Caller. SecurityAgent may only be invoked by Apple software." appearing right before the Login Window appeared
- If I could get logged in, Dock icons frequently were missing
- If I could get logged in, the computer would eventually slow down to a grinding, useless speed.

My solution was essentially the same as pointed to in the above post by jhalvorson:

NetBoot Error: Startup Disk is Almost Full
https://jamfnation.jamfsoftware.com/article.html?id=198

However I used a sparse disk image so the 10GB of space was not actually used in the final NBI dmg. Note that my Mountain Lion utility NBI (InstaDMG -> SIU) did still complain about low free disk space, but never died in the fashion the Mavericks NBI did.

[CasperSally]

thanks for trying to help @foigus - It's not complaining about startup disk almost full. I'm using the utah rc.netboot file to use a RAM disk since we've had diskless issues in the past. So when we netboot, an untitled drive mounts, when I do get info on that drive it is 256MB and as imaging process goes, the available number of MB decreases.

On 10.8 NBI the untitled drive never gets under 100MB available.
On 10.9 NBI, with same rc.netboot file & same imaging config, untitled goes below 100 available about 1/3 of the way into the packages and eventually goes to zero. When it goes to zero, packages appear to install quickly, but in reality they are being skipped with no error present in casper imaging. I only know the packages aren't installed because I look in Applications folder and the last few packages set to install aren't there.

The 10.9 NBI was 9 gigs. I did the hdiutil to 15 gigs but same issue persists.

[foigus]

Are you using an unmodified University of Utah rc.netboot file from here:

http://www.macos.utah.edu/documentation/administration/setup_netboot_service_on_mac_os_x_10.6.x_clie...

The default RAM disk scratch space in that rc.netboot file is "rdsize=500000", which provides 500000 512-byte blocks--a 256MB RAM disk. It might have been possible to use 10.6 with 256MB of RAM, but later versions of OS X are more demanding.

The math to get a larger RAM disk:
1GB=((11024^3)/512)=2097152 512-byte blocks
2GB=((21024^3)/512)=4194304 512-byte blocks

My edited University of Utah NetBoot file (when I do use it) has the following (including the comment so I can do the math easily again in the future):
rdsize=4194304 #1GB ((11024^3)/512)=2097152, 2GB=((21024^3)/512)=4194304

I had someone on Twitter share that 1GB was sufficient for them, but I upped it to 2GB for my use.

Many thanks to this AFP548 post/comment:
http://www.afp548.com/2011/02/01/serving-diskless-netboot-for-your-macs-without-os-x-server/#comment...

[CasperSally]

I tried using the unmodified version (and my modified version, but I hadn't modified that line - didn't think to look where that 256 was coming from).

I bet that's what I probably need. will give it a try... thanks for taking the time to respond again @foigus][/url!

[macbook]

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