Notes on migrating / upgrading Samba PDC to AD

Notes on upgrading/migrating a Samba 3 PDC to a Samba 4 AD on a totally separate system.

Scenario (in my case):

• Running an older Samba 3 release with a tdbsam backend as a PDC, file and print server on an older distro that cannot be (easily, if at all) upgraded.
• A need to move to Active Directory technology.
• Will use best practices - keeping the AD server separate from the file and printer server.
• The new AD will be on a new server with a different hostname and IP address. The old PDC will remain running until the new AD is in place and tested.

Most info for doing this is detailed in the link below:

Migrating a Samba NT4 Domain to Samba AD (Classic Upgrade)

Some gotchas are detailed in:

Avoiding common problems

Another gotcha that I ran into was that my old PDC was using a local Windows built-in group (Print Operators in this case), and such mapped groups will cause the classicupgrade process to fail.

What isn’t immediately realized (or wasn’t by me) is that if you just take a brand new Samba install on a brand new server and attempt the classicupgrade process as detailed above there will be problems. The reason is that Samba PDC databases do not contain all of the information necessary to do the upgrade. The users, machines, and groups all exist in ‘nix land and are necessary to that environment.

Even though the new AD (again operating as just an AD) itself does not need the ‘nix equivalent users and groups for proper operation, the upgrade process does.

It is necessary to create the same users (including machines) and groups on the new “virgin” box. It is not necessary to match UID’s of the users or machines but the GID’s of the groups must match, and the users need to added to the groups they are members of.

Once the upgrade is complete and the AD is up and running the added ‘nix users and groups can be removed.

Fedora install issue - The system may not be bootable.

If you see this error message when installing Fedora (was version 22 in my case):

There was an error installing the bootloader. The system may not be bootable.

Remind yourself  that the system may be bootable!

The first 5 times I elected to stop the install (why continue if the system wont boot?). But the sixth time around after doing everything I could to verify it should be working I elected to go ahead with the install even though "The system may not be bootable.".

Guess what happened?

It didn't boot.

But the only reason it didn't boot was because the system was set to boot in BIOS mode and not in UEFI mode that I used when booting the install stick. Apparently the installer was unable to change the system's default boot selection. I went into the system setup and changed the default boot device to UEFI mode and the proper drive, booted again, and it all worked perfectly.

Possibly if the default boot setup had previously been set as such I may have never seen that message.

Fix error 0x000006d1 using level 3 print drivers from Samba to Windows 8

Ran across error 0x000006d1 when attempting to add Samba shared printers to Windows 8 systems. The following fixed the issue for me. This may also help for earlier versions of Windows but I've only run across the problem with some (not all) Windows 8 systems.

nVidia with Ubuntu - no X or low graphics mode

After updates and a reboot, Ubuntu 12.04(.1) reports low graphics mode and/or X does not start when using the nVidia driver.

I've seen this problem on two systems recently and it appears to be a timing issue in that the nVidia driver does get loaded but apparently not in time for X to find a valid screen.

Workaround is simple: add nvidia to the file /etc/modules it will then get loaded on boot and X will start normally.

EFI Stub - booting without a bootloader

In this post I'm detailing a quick and easy method to use EFI Stub boot introduced in the Linux kernel version 3.3.0 that provides for a faster boot without the use of a bootloader (such as grub) on a UEFI capable system.

no bootable device - gpt

Some legacy BIOS's may have an issue with a GPT partitioned drive.


Ran across this recently with an Intel D975XBX board. I GPT partitioned a drive with gdisk, installed Ubuntu and when I rebooted after the install completed with surprised to see "No Bootable Device..." displayed.

CUPS Samba 64bit automatic driver download

The same ease of using Samba hosting for automatic download of the CUPS/Windows Postscript drivers for 32 bit clients can be implemented for 64 bit clients as well.

NT4 inaccessible_boot_device

I recently needed to boot a cloned image of an old NT4 system under a virtual machine. Of course, nothing is easy sometimes. In this case I was using VirtualBox as between it and Qemu(KVM) it seemed to have the best support for NT4. However it didn't emulate the Adaptec SCSI hardware that the original system used and boot attempts were met by the famous BSOD with inaccessible_boot_device. Loading up a new VM with NT4 and booting with /sos (selecting VGA mode is one way) to see what drivers were being loaded the difference was that the new install loaded ATAPI.SYS and the cloned image was loading AIC78xx.SYS, which gave me an idea. I booted the cloned image from a SystemRescueCD mounted the "C:" drive with ntfs-3g and copied the ATAPI.SYS driver over the AIC78xx.SYS driver as AIC78xx.SYS and voila, the system now boots! Not claiming this will work in every case but it did work in this one.

Samba and guest shares with "security = user"

How to have a guest share on Samba without resorting to the deprecated "security = share" configuration.

This is a regular query on the Samba mailing list. When it comes to "security = share" just say no!

Practice safe and secure SSH !

Some tips to consider when using SSH.

Probably the most ubiquitous piece of software in use is OpenSSH. It is from the developers that also bring us that most secure OS, OpenBSD. We all use it, we all love it, we all depend on it. Please donate to these great projects if you can! And read on for the tips...

Add bootable DOS support to your USB stick

Building on the previous post where we added SystemRescueCD capabilities to our USB stick (please see that post for details and conventions that pertain to this one as well) while still being able to use it for transferring files between various OS, we will now add bootable DOS support so that we can use it for BIOS updates as well as other DOS based tools such as Intel's SSD firmware updater.

Add SystemRescueCD capability to your USB stick

For Linux users: Creating a bootable SystemRescueCD USB stick. The SystemRescueCD is an invaluable resource and should be in every techs toolkit. Kudos and much thanks to the developers!

Ubuntu install hangs on partitioning @43%

Many sites are recommending setting up the partition table on an SSD using:

• fdisk -H 32 -S 32 /dev/sdx

Unfortunately for a complex partitioning scheme this causes Ubuntu partman to hang during installation (at 43% in my case).

I discovered that:

• fdisk -H 224 -S 56 /dev/sdx

Works just fine.

Overview for installing Ubuntu via network

Simple overview for installing Ubuntu via network.

• Ubuntu Server is the OS we will install in this guide.
• Note: this is just the big picture, other guides can instruct on setting up the various DHCP, DNS, TFTP, and HTTP servers.
• The main idea is to focus on the fact that once the detail work is done (and most local networks have these setup) there's basically only 3 major steps to net install nirvana.