samba - Oct 2017 - Replication Error Between Differing Samba Versions During Upgrade

Hey all-

Trying to upgrade the domain and running into issues getting my data into the
new controller.

Current configuration:
dc0 - Ubuntu 12.04.2 - Samba: 2:4.0.6-12
dc1 - Ubuntu 12.04.2 - Samba: 2:4.0.6-8
dc2 - Ubuntu 12.04.3 - Samba: 2:4.0.6-8

I'm trying upgrade to Ubuntu 16.04.3, Samba: 2:4.3.11+dfsg-0ubuntu0.16.04.10

The documentation
(https://wiki.samba.org/index.php/Updating_Samba#The_Update_Process) recommends
updating in place, but the standard practice I have to work around is to create
a new server and decommission old servers. In my test instance, I'm trying
to do
this by introducing dc3 already at the OS and Samba version listed above. This
section
(https://wiki.samba.org/index.php/Updating_Samba#Updating_Multiple_Samba_Domain_Controllers)
suggests that running different versions of domain controllers in the same
domain is OK and should not be the inherent problem.

The current state of things is that for dc0, dc1, dc2:
* "samba-tool dbcheck --cross-ncs" returns no errors
* "samba-tool drs showrepl" returns no errors (and just the expected
warning about "No NC replicated for Connection")
* "samba-tool ldapcmp --filter=msDS-NcType,serverState,subrefs"
returns no errors

dc3 is a bit funky:
* attempts to connect to this dc in ADUC results in "The RPC server is
unavailable"
* "samba-tool dbcheck --cross-ncs" returns no errors
* "samba-tool drs showrepl" returns no errors (and just the expected
warning about "No NC replicated for Connection")
* "samba-tool ldapcmp --filter=msDS-NcType,serverState,subrefs"
returns a HUGE amount of errors, e.g.:

Comparing:
'CN=NTDS Quotas,DC=example,DC=com' [ldap://dc0.example.com]
'CN=NTDS Quotas,DC=example,DC=com' [ldap://dc3.example.com]
    Attributes found only in ldap://dc0.example.com:
        distinguishedName
        isCriticalSystemObject
        cn
        name
        objectCategory
        objectClass
        msDS-TombstoneQuotaFactor
        objectGUID
        systemFlags
        whenCreated
        showInAdvancedViewOnly
        instanceType
        description
    FAILED

Forcing replication from a good domain controller "samba-tool drs replicate
dc3
dc0 'DC=EXAMPLE,DC=COM'" returns successfully but does not remove
any of the
errors shown from the ldapcmp command. Adding the "--sync-forced --sync-all
--full-sync" flags does not change the outcome. Replicating on all the NCs
(e.g.
"CN=Configuration,DC=EXAMPLE,DC=COM") does not change the outcome.


I also found that the LDB databases (which I believe are initially populated on
domain join) are missing data. On one of the old controllers, "ldbsearch -H
/var/lib/samba/private/sam.ldb.d/DC%3DEXAMPLE,DC%3DCOM.ldb -b
"cn=dc0,OU=Domain
Controllers,DC=EXAMPLE,DC=COM"" returns good data:

# record 1
dn: CN=DC0,OU=Domain Controllers,DC=example,DC=com
objectClass: top
objectClass: person
objectClass: organizationalPerson
objectClass: user
objectClass: computer
cn: DC0
instanceType: 4
whenCreated: 20130703181107.0Z
uSNCreated: 3583

But on dc3, it returns only:

# record 1
dn: CN=DC0,OU=Domain Controllers,DC=example,DC=com

# record 2
dn: CN=RID Set,CN=DC0,OU=Domain Controllers,DC=example,DC=com

# returned 2 records 2 entries 0 referrals



Before I ran into this issue, I was having issues just getting replication to
work at all ("samba-tool drs showrepl" would show errors). dc3
complained about
WERR_GENERAL_FAILURE from dc0 and dc1 (it is unclear why, but dc3 never
complained about dc2). After spending a long time looking and checking many
other things, I eventually found this thread
https://lists.samba.org/archive/samba/2014-August/184479.html. While the
original author seems to not have needed it, I found that this level of
replication issue (WERR_GENERAL_FAILURE) was fixed by adding the GUID CNAME
records to /etc/hosts file of dc3. Other than that, I have not done anything to
the domain controller after provisioning it (to my recollection -- it's been
a
long couple of days).


I've copied the running domain into an isolated environment and can play
with it
without impacting any users/services, so feel free to recommend anything.


Thanks,

Mike Ray

Spent more time on this today and found the following:
* manually copying over the sam.ldb from a working controller did not fix the 
  broken controller (in fact, it completely destroyed the domain)
* upgrading to 4.1.6 shows the same issue as 4.3.11 (dbcheck, drs showrepl,
  dnsupdate all return happily, but ldapcmp shows missing data in the new
  controller)
* this issue does not show up if I add another 4.0.6(*) dc

(*) - this is a bastardize, custom version, not true "4.0.6"

My next step is to try just getting a 4.0.7 controller to work. If that fails,
just a 4.0.6.

My current theory is that at some point the replication code was changed to ask
for data in a way that isn't compatible with the old version, but that if I
do
smaller version upgrades, it'll handle it internally. If anyone has any 4.0
to
4.1 upgrade information/links, I would appreciate them.

----- On Sep 29, 2017, at 5:37 PM, samba samba at lists.samba.org wrote:
> Hey all-
> 
> Trying to upgrade the domain and running into issues getting my data into
the
> new controller.
>

Hello all-

At the recommendation of the Catalyst team, instead of trying to get 4.0.6
replicating with 4.0.7, they suggested we try a later version (>=4.5) as
those
versions are much more recent and may have handled issues older versions just
could not. Unfortunately that too did not work. They then suggested that an
in-place upgrade, as if there was a bug in our 4.0.6 code that was causing
problems, there was not much else that could be done. The server survived an
upgrade from Ubuntu 12.04 (Samba 4.0.6) to Ubuntu 14.04 (Samba 4.3.11) with
minimal work afterwards (samba-dsdb-modules and samba-vfs-modules packages were
missing) and seemingly no loss of data.

We still plan on going up to 4.7 via SerNet packages or similar, but at
this point it seems we are out of the woods.

TL;DR - we fixed a replication issue that was blocking an upgrade by first
upgrading our existing hosts.

----- On Oct 2, 2017, at 5:32 PM, Mike Ray mray at xes-inc.com wrote:
> Spent more time on this today and found the
following: