Archive for the ‘Mac OS X’ Category

Identifying which Active Directory account is logged into Enterprise Connect

April 12, 2017 4 comments

As more Mac environments move away from binding Macs to Active Directory and using AD mobile accounts, and towards using local accounts in combination of tools like NoMAD and Apple’s Enterprise Connect, it’s become more challenging to identify which people are logged into which computers. While mobile Active Directory accounts will use the username and password of the person’s AD account, there is no such certainty with local user accounts.

Fortunately, my colleague Joe Chilcote recently let me know that it’s possible to query the logged-in user’s login keychain and get the username of the Active Directory account which is logged into Enterprise Connect. This can be accomplished by running the following command as the logged-in user:

/usr/bin/security find-generic-password -l "Enterprise Connect" $HOME/Library/Keychains/login.keychain | awk -F "=" '/acct/ {print $2}' | tr -d "\""

That should produce output similar to that shown below:

computername:~ username$ /usr/bin/security find-generic-password -l "Enterprise Connect" $HOME/Library/Keychains/login.keychain | awk -F "=" '/acct/ {print $2}' | tr -d "\""
computername:~ username$

It’s also possible to leverage this technique to update the User and Location section of a particular computer managed by a Jamf Pro server. For more information, see below the jump.

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Building VMs on ESXi using

April 11, 2017 1 comment

As part of my testing workflow, I’ve been using VMs running on a ESXi server running ESXi 6.5. To help me quickly build those VMs, I have been using a script named for building VMs. This script is forked from Tamas Piros’s auto-create script for standing up Linux VMs on free ESXi:

My fork of the auto-create script is designed to create and configure virtual machines with Apple operating systems as the guest OS, hosted on a VMware ESXi server running on Apple hardware. The script assumes that the virtual machines are built using copied VMDK disk files, where the VMDK files are generated by AutoDMG and vfuse. For more details, see below the jump.

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Expanding partition size in an ESXi-hosted macOS VM

April 9, 2017 Leave a comment

As part of working on a project recently, I ran into an unexpected problem with ESXi-hosted Mac VMs. For these VMs, I was creating VMDK files from AutoDMG-generated disk images, using vfuse to convert the disk image into a VM with ESXi-compatible VMDK disk image files.

My workflow looked like this:

1. Create disk image using AutoDMG.
2. Use vfuse to create VMDK files using a command similar to the one shown below:

sudo vfuse -i /path/to/autodmg_created_disk_image_here --esx

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3. Upload the VMDK files to a convenient location on my ESXi server
4. Set up a new VM, using copies of uploaded VMDK files for the VM boot disk.
5. Resize the new VM to the desired size using VMware’s vmkfstools utility.
6. Start up the VM.

After logging in, I ran the following command to enable macOS to recognize and use the unallocated space from the VM resizing:

diskutil resizeVolume / R

Normally, this command is able to do a live re-sizing of the boot partition to use all available unallocated space. However, this time the re-sizing process failed and the following error was displayed:

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How to fix this? For more details, see below the jump.

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Creating macOS installer disk images for VMware Fusion and ESXi with create_macos_vm_install_dmg

March 30, 2017 Leave a comment

I’ve had a tool available for a while named create_vmware_osx_install_dmg, but it looks like it has reached the end of the road with macOS 10.12.3. The reason for this is because macOS 10.12.4 has introduced a change that prevents the addition of third-party packages to the OS installer. create_vmware_osx_install_dmg uses the addition of a third-party installer package, so unfortunately this tool cannot be used to generate 10.12.4 or later OS installers.

That said, I still want to be able to create macOS installer disk images for VMware Fusion and ESXi, so I’ve forked create_vmware_osx_install_dmg into a new script named create_macos_vm_install_dmg. create_macos_vm_install_dmg will generate stock OS installer disk images for the following OS versions:

  • Mac OS X 10.7.x
  • OS X 10.8.x
  • OS X 10.9.x
  • OS X 10.10.x
  • OS X 10.11.x
  • OS X 10.12.x

This script does not use a third-party package, so it is able to build a macOS 10.12.4 installer disk image. For more details, see below the jump.

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Creating multiline login banners

March 25, 2017 2 comments

In a number of Mac environments, there is a need or requirement for a login banner (otherwise known as a lock message). This message appears in the following locations:

  • FileVault 2 pre-boot login screen
  • OS login window
  • Screensaver lock window

Brevity is best, as staying within a maximum of three lines permits the banner text to be displayed consistently in all three locations. Exceeding the three-line limit may result in the text being cut off and not fully displayed.

You can set this banner text from the command line using the following defaults command, which should be run with root privileges:

/usr/bin/defaults write /Library/Preferences/ LoginwindowText "My Login Window Text Goes Here"

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Being able to consistently set when lines begin and end can be challenging though, as the defaults command is not able to interpret a newline command natively. However, it is possible to set a multi-line login banner and be able to consistently set when lines begin and end. For more details, see below the jump.

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Disabling login to the root account by changing the root account’s user shell

March 19, 2017 1 comment

While discussing various issues with a colleague, he mentioned that he was seeing the root account enabled on several machines where it should not have been. In general, the root account on macOS is not needed for system administration and should be disabled so he asked if there was a way to use the dsenableroot command to disable the root account without also needing to provide a password.

Unfortunately, disabling the root account by using the dsenableroot -d command does require providing a password as part of the command.

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However, it is possible to disable logins to the root account without using the dsenableroot -d command. For more details, see below the jump.

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Resizing a virtual machine’s boot drive to use all available space

March 3, 2017 2 comments

Every so often, it’s necessary to resize the boot drive of an existing virtual machine. The process of resizing the VM’s boot disk from outside the VM is usually pretty straightforward:

1. Shut down the VM
2. Go into the VM’s drive settings

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3. Resize it to the desired size

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4. Power on the VM.

However, when the VM boots up, the disk space used by the OS won’t have changed.

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However, the OS can detect that there is available unallocated disk space that it isn’t using.

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Fortunately, this is a correctable condition and the fix can be applied without needing to shut down the VM or boot from another drive. For more details, see below the jump.

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