Migrating a Samba NT4 Domain to Samba AD (Classic Upgrade)
PRENOTE This guide is only for replacing the 4th step (Step 4: Provision Samba4) on the main Samba4/HOWTO wiki page. Please follow that page in full detail before attempting anything on this page.
This is a very early beginning of a HOWTO for the Samba3 to Samba4 upgrade process
The Samba Tool (see: Samba-tool-external) is a collection of tools and scripts used to build, manage and debug a Samba4 instance.
The samba3upgrade is a function built into the samba-tool. The intent of this function is to do a full replacement of an existing Samba3 supported domain. It is possible (at least in theory) to do the conversion of an existing Samba3 domain, shut down the old service and start the new Samba4 service, and the Windows users and member computers will simply connect to the new server without needing to manually re-join. Existing user domain profiles on member computers will appear exactly as they did on the old domain.
PLEASE NOTE: Make sure you thoroughly test your conversion and how your clients react before you activate your new server in your production environment! Once a Windows client finds and connects to the new server, it is not possible to go back! It is necessary to do testing on a separate network so that the old and new domain controllers don't clash.
The issues with having both domains 'live' at the same time are:
- The databases are not syncronised after the initial migration
- Even if no changes are made to the DB, clients which see an AD DC will no longer honour NT4 system policies
- The new Samba4 PDC and the old DC will both claim to hold the #1b name as the netbios domain master
Notes about migrating from LDAP backend
Make sure you have the ldap headers (apt-get install libldap2-dev for debian based distros) Double check that either:
- A) you have 'ldapsam:trusted = yes' in the [global] section of your Samba3 config file or
- B) you have nsswitch.conf configured with the correct ldap entries.
Otherwise certain parts of the migration process wont complete correctly. (I had specific problems with group migration)
The following will check for duplicate SID's using slapcat, you will want to fix these manually before running the samba3upgrade command, otherwise the import will have problems.
#!/usr/bin/python # A quick and dirty python script that checks for duplicat SID's using slapcat. import os data = os.popen("slapcat | grep sambaSID", 'r') line =  def anydup(thelist): dups = list(set([x for x in thelist if thelist.count(x) > 1])) for i in dups: print "Duplicate id: ", i for each_line in data: line.append(each_line.strip()) anydup(line)
Upgrading on a New Server (testing before an inplace migration PREFERRED)
It is possible to copy your domain information from the existing Samba3 domain to a new server and do your conversion there.
Download, build and install the Samba4 binaries, either from one of the Alpha releases or from "git". (see the Samba4/HOWTO page, follow the howto all the way to the provision step)
Copy your Samba3 database directory (the location of all your Samba3 tdb files mine is /var/lib/samba) to the new server (eg, scp -r /var/lib/samba ip.to.new.server:/home/user/samba3db) as well as the Samba3 config (mine is /etc/samba/smb.conf, so scp /etc/samba/smb.conf ip.to.new.server:/home/user/samba3.conf). You will also want to copy over and configure LDAP if you are coming from that backend. (scp -r /var/lib/ldap ip.to.new.server:/home/user/ldapdb) [NOTE: samba3 does not need to be installed on this machine, only the db and config files copied over, LDAP however does need to be installed if you are coming from that backend]
If you wish to rename the new server, you can change the netbios name in the Samba3 conf file.
[NOTE: if you run the migration more than once, for example, in a testing environment, then make sure you remove the generated conf file in /usr/local/samba/etc directory. If the migration tool finds an existing smb.conf file, it will make use of the parameters there in its conversion.]
# /usr/local/samba/bin/samba-tool domain samba3upgrade --dbdir=/home/user/samba3db --use-xattrs=yes --realm=myname.org /home/user/samba3.conf (this will need done with root permissions add | tee /samba3upgrade.log to capture the output)
You can toggle the samba loglevel in the samba3.conf to see extra output if you are having problems, be aware that this may cause MASSIVE amounts of output.
- use-xattrs: use the underlying file system support for extended attributes. This assumes that your host OS supports this.
- realm: You can specify the realm on the command line if it is not already specified in the Samba3 smb.conf file.
Upgrading in Place
Only after you have done a successful upgrade on another machine should you do this step.
One way to create a new Samba4 server is to install the Samba4 binaries on a currently existing Samba3 server. This will replace the currently running system with a Samba4 instance, populated with the users, groups and machine accounts from the previous Samba3 service.
- First: follow the first 3 steps from the Samba4/HOWTO page
- Second: stop all existing Samba3 services (smbd, nmbd, winbindd) but leave slapd running if you are moving from ldap backend.
- Third: preform the upgrade by doing a
# /usr/local/samba/bin/samba-tool domain samba3upgrade --dbdir=/path/to/samba3/tdbfiles --use-xattrs=yes --realm=myname.org /path/to/samba3/smb.conf (this will need done with root permissions)
- Fourth: Stop slapd and start samba 4 (follow from step 5 on using the Samba4/HOWTO page)
- Fifth: VERY IMPORTANT Make sure the Samba3 and LDAP services DO NOT autostart on next boot. Look around the internet to find out how to stop them from starting, this is distro specific. Also, this is a good step to make sure that Samba4 DOES start on boot
Please share any notes about your migration here!
I kept getting messages about expired passwords, this was an early bug that has since been fixed, but if you need to extend your password times do the following:
# samba-tool domain passwordsettings set --max-pwd-age=999