autobuild[sn-devel-144]: intermittent test failure detected

[autobuild]

The autobuild test system (on sn-devel-144) has detected an intermittent failing test in 
the current master tree.

The autobuild log of the failure is available here:

   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-09-26-1857/flakey.log

The failure seems to be in the "samba-py3" suite, whose build logs are available here:

   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-09-26-1857/samba-py3.stderr
   https://git.samba.org/autobuild.flakey.sn-devel-144/2018-09-26-1857/samba-py3.stdout
  
The top commit at the time of the failure was:

commit 36cb85be726e03c482b82f0af7eed2c81f8df35a
Author: Douglas Bagnall <douglas.bagnall at catalyst.net.nz>
Date:   Fri Sep 21 11:26:35 2018 +1200

    samba-tool domain backup: fix py2.6 incompatible format
    
    Signed-off-by: Douglas Bagnall <douglas.bagnall at catalyst.net.nz>
    Reviewed-by: Andrew Bartlett <abartlet at samba.org>
    
    Autobuild-User(master): Andrew Bartlett <abartlet at samba.org>
    Autobuild-Date(master): Wed Sep 26 10:40:49 CEST 2018 on sn-devel-144

and the last 50 lines of the stdout log were:

[59(527)/75 at 26m49s] samba4.drs.link_conflicts.python(promoted_dc).python3(promoted_dc)
[60(539)/75 at 28m53s] samba4.drs.repl_schema.python(vampire_dc).python3(vampire_dc)
[61(548)/75 at 29m35s] samba4.drs.repl_schema.python(promoted_dc).python3(promoted_dc)
[62(557)/75 at 30m23s] samba4.drs.getncchanges.python(vampire_dc).python3(vampire_dc)
[63(569)/75 at 32m6s] samba4.drs.getncchanges.python(promoted_dc).python3(promoted_dc)
[64(581)/75 at 34m3s] samba4.drs.repl_rodc.python(ad_dc_ntvfs).python3(ad_dc_ntvfs)
[65(589)/75 at 34m36s] samba.tests.join.python(ad_dc_ntvfs).python3(ad_dc_ntvfs)
[66(591)/75 at 36m26s] samba4.drs.cracknames.python(ad_dc_ntvfs).python3(ad_dc_ntvfs)
[67(594)/75 at 36m28s] samba.tests.kcc.python3(vampire_dc)
UNEXPECTED(error): samba.tests.kcc.python3.samba.tests.kcc.KCCTests.test_list_dsas(vampire_dc)
REASON: Exception: Exception: Traceback (most recent call last):
  File "bin/python/samba/kcc/kcc_utils.py", line 652, in load_dsa
    attrs=attrs)
_ldb.LdbError: (32, 'LDAP error 32 LDAP_NO_SUCH_OBJECT -  <acl_read: Error retrieving instanceType for base. at ../source4/dsdb/samdb/ldb_modules/acl_read.c:759> <>')

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "bin/python/samba/tests/kcc/__init__.py", line 65, in test_list_dsas
    dsas = my_kcc.list_dsas()
  File "bin/python/samba/kcc/__init__.py", line 2448, in list_dsas
    self.load_all_sites()
  File "bin/python/samba/kcc/__init__.py", line 249, in load_all_sites
    self.load_site(sitestr)
  File "bin/python/samba/kcc/__init__.py", line 207, in load_site
    site.load_site(self.samdb)
  File "bin/python/samba/kcc/kcc_utils.py", line 1508, in load_site
    self.load_all_dsa(samdb)
  File "bin/python/samba/kcc/kcc_utils.py", line 1532, in load_all_dsa
    dsa.load_dsa(samdb)
  File "bin/python/samba/kcc/kcc_utils.py", line 657, in load_dsa
    (self.dsa_dnstr, estr))
samba.kcc.kcc_utils.KCCError: Unable to find nTDSDSA for (CN=NTDS Settings,CN=jointest1,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration,DC=samba,DC=example,DC=com) - (LDAP error 32 LDAP_NO_SUCH_OBJECT -  <acl_read: Error retrieving instanceType for base. at ../source4/dsdb/samdb/ldb_modules/acl_read.c:759> <>)

FAILED (0 failures, 1 errors and 0 unexpected successes in 0 testsuites)

A summary with detailed information can be found in:
  ./bin/ab/summary
TOP 10 slowest tests
samba4.drs.link_conflicts.python(vampire_dc).python3(vampire_dc) -> 199
samba4.drs.ridalloc_exop.python(vampire_dc).python3(vampire_dc) -> 167
samba4.drs.link_conflicts.python(promoted_dc).python3(promoted_dc) -> 124
samba4.drs.getncchanges.python(promoted_dc).python3(promoted_dc) -> 117
samba4.drs.repl_move.python(vampire_dc).python3(vampire_dc) -> 111
samba.tests.join.python(ad_dc_ntvfs).python3(ad_dc_ntvfs) -> 110
samba4.drs.samba_tool_drs.python(vampire_dc).python3(vampire_dc:local) -> 107
samba4.drs.getncchanges.python(vampire_dc).python3(vampire_dc) -> 103
samba4.drs.samba_tool_drs.python(promoted_dc).python3(promoted_dc:local) -> 98
samba.tests.emulate.traffic_packet.python3(ad_dc_ntvfs) -> 93
ERROR: test failed with exit code 1