Log indicated that the postinstall_rootfs task did not work:

-------------
• workdir : /home/pokybuild/yocto-autobuilder/yocto-worker/nightly-oe-selftest
Detailed log of last build step: https://autobuilder.yocto.io/builders/nightly-oe-selftest/builds/598/steps/Running oe-selftest/logs/stdio
Last 60 lines of "Running oe-selftest.stdio" Error log:

2017-11-06 03:43:24,962 - oe-selftest - INFO - ... ERROR (4567.022s)
2017-11-06 05:17:54,558 - oe-selftest - INFO - ERROR [0.000s]: test_postinst_rootfs_and_boot (runtime_test.Postinst)
2017-11-06 05:17:54,566 - oe-selftest - INFO - ERROR [4567.022s]: test_postinst_rootfs_and_boot (runtime_test.Postinst)
-----------

Looking into the AB log:

------
2017-11-06 05:17:54,558 - oe-selftest - INFO - ======================================================================
2017-11-06 05:17:54,558 - oe-selftest - INFO - ERROR [0.000s]: test_postinst_rootfs_and_boot (runtime_test.Postinst)
2017-11-06 05:17:54,558 - oe-selftest - INFO - ----------------------------------------------------------------------
2017-11-06 05:17:54,559 - oe-selftest - INFO - Traceback (most recent call last):
  File "/home/pokybuild/yocto-autobuilder/yocto-worker/nightly-oe-selftest/build/meta/lib/oeqa/selftest/cases/runtime_test.py", line 268, in test_postinst_rootfs_and_boot
    self.assertEqual(status, 0, 'File %s was not created at first boot (%s)' % (fileboot_name, output))
AssertionError: 1 != 0 : File this-was-created-at-first-boot was not created at first boot (ls: /etc/this-was-created-at-first-boot: No such file or directory)

Stdout:
Previous bitbake instance shutting down?, waiting to retry...
WARNING: /home/pokybuild/yocto-autobuilder/yocto-worker/nightly-oe-selftest/build/bitbake/lib/bb/parse/parse_py/BBHandler.py:96: ResourceWarning: unclosed file <_io.TextIOWrapper name=44 mode='w' encoding='UTF-8'>
  s = f.readline()
-----

AB build info:

-------
Build status: FAILURE Build worker for this Build: debian9.yocto.io
Complete logs for all build steps: https://autobuilder.yocto.io/builders/nightly-oe-selftest/builds/598
Build Reason: Triggerable(trigger_main-build_nowait)
Build Properties:
• Contents of bblayers.conf (Note. LCONF_VERSION will not show up correctly)
POKY_BBLAYERS_CONF_VERSION =
BBPATH = "${TOPDIR}"
BBFILES ?=""
BBLAYERS &#43;= " \
/home/pokybuild/yocto-autobuilder/yocto-worker/nightly-oe-selftest/build/meta \
/home/pokybuild/yocto-autobuilder/yocto-worker/nightly-oe-selftest/build/meta-poky \
/home/pokybuild/yocto-autobuilder/yocto-worker/nightly-oe-selftest/build/meta-yocto-bsp \
/home/pokybuild/yocto-autobuilder/yocto-worker/nightly-oe-selftest/build/meta-selftest \
"

• DEST : /srv/autobuilder/autobuilder.yoctoproject.org/pub/nightly/20171105-4
• DISTRO : poky
• Contents of auto.conf (local.conf for autobuilders)
INHERIT &#43;= "report-error"
DISTRO = "poky"
PACKAGE_CLASSES = "package_rpm"
BB_NUMBER_THREADS = "24"
PARALLEL_MAKE = "-j 28"
SDKMACHINE ?= "x86_64"
BB_TASK_NICE_LEVEL = "5"
BB_TASK_NICE_LEVEL_task-testimage = "0"
BB_TASK_IONICE_LEVEL = "2.7"
BB_TASK_IONICE_LEVEL_task-testimage = "2.1"
DL_DIR = "/srv/autobuilder/autobuilder.yoctoproject.org/current_sources"
SSTATE_DIR ?= "/srv/autobuilder/autobuilder.yoctoproject.org/pub/sstate/"
MACHINE = "qemux86-64"
PREMIRRORS = ""
BB_GENERATE_MIRROR_TARBALLS = "1"
ADTREPO = "http://adtrepo.yoctoproject.org//2.4"
QEMU_USE_KVM = "True"
SDK_EXT_TYPE = "minimal"
SDK_INCLUDE_TOOLCHAIN = "1"
SANITY_TESTED_DISTROS = ""
RPM_GPG_SIGN_CHUNK = "1"
-----