diff --git a/tests/fixtures/config/job-output/git/common-config/playbooks/job-output-failure-post.yaml b/tests/fixtures/config/job-output/git/common-config/playbooks/job-output-failure-post.yaml
new file mode 100644
index 0000000..bd46718
--- /dev/null
+++ b/tests/fixtures/config/job-output/git/common-config/playbooks/job-output-failure-post.yaml
@@ -0,0 +1,4 @@
+- hosts: all
+  tasks:
+    - shell: echo "Failure test {{ zuul.executor.src_root }}"
+    - shell: exit 1
diff --git a/tests/fixtures/config/job-output/git/common-config/zuul.yaml b/tests/fixtures/config/job-output/git/common-config/zuul.yaml
index a83f0bc..f182d8d 100644
--- a/tests/fixtures/config/job-output/git/common-config/zuul.yaml
+++ b/tests/fixtures/config/job-output/git/common-config/zuul.yaml
@@ -20,8 +20,19 @@
     parent: base
     name: job-output
 
+- job:
+    name: job-output-failure
+    run: playbooks/job-output
+    post-run: playbooks/job-output-failure-post
+
 - project:
     name: org/project
     check:
       jobs:
         - job-output
+
+- project:
+    name: org/project2
+    check:
+      jobs:
+        - job-output-failure
diff --git a/tests/fixtures/config/job-output/git/org_project2/README b/tests/fixtures/config/job-output/git/org_project2/README
new file mode 100644
index 0000000..9daeafb
--- /dev/null
+++ b/tests/fixtures/config/job-output/git/org_project2/README
@@ -0,0 +1 @@
+test
diff --git a/tests/fixtures/config/job-output/main.yaml b/tests/fixtures/config/job-output/main.yaml
index 208e274..14b382f 100644
--- a/tests/fixtures/config/job-output/main.yaml
+++ b/tests/fixtures/config/job-output/main.yaml
@@ -6,3 +6,4 @@
           - common-config
         untrusted-projects:
           - org/project
+          - org/project2
diff --git a/tests/unit/test_v3.py b/tests/unit/test_v3.py
index 327d457..99c87e0 100755
--- a/tests/unit/test_v3.py
+++ b/tests/unit/test_v3.py
@@ -14,7 +14,9 @@
 # License for the specific language governing permissions and limitations
 # under the License.
 
+import io
 import json
+import logging
 import os
 import textwrap
 import gc
@@ -1844,7 +1846,8 @@
             return f.read()
 
     def test_job_output(self):
-        # Verify that command standard output appears in the job output
+        # Verify that command standard output appears in the job output,
+        # and that failures in the final playbook get logged.
 
         # This currently only verifies we receive output from
         # localhost.  Notably, it does not verify we receive output
@@ -1869,3 +1872,36 @@
         self.assertIn(token,
                       self._get_file(self.history[0],
                                      'work/logs/job-output.txt'))
+
+    def test_job_output_failure_log(self):
+        logger = logging.getLogger('zuul.AnsibleJob')
+        output = io.StringIO()
+        logger.addHandler(logging.StreamHandler(output))
+
+        # Verify that a failure in the last post playbook emits the contents
+        # of the json output to the log
+        self.executor_server.keep_jobdir = True
+        A = self.fake_gerrit.addFakeChange('org/project2', 'master', 'A')
+        self.fake_gerrit.addEvent(A.getPatchsetCreatedEvent(1))
+        self.waitUntilSettled()
+        self.assertHistory([
+            dict(name='job-output-failure',
+                 result='POST_FAILURE', changes='1,1'),
+        ], ordered=False)
+
+        token = 'Standard output test %s' % (self.history[0].jobdir.src_root)
+        j = json.loads(self._get_file(self.history[0],
+                                      'work/logs/job-output.json'))
+        self.assertEqual(token,
+                         j[0]['plays'][0]['tasks'][0]
+                         ['hosts']['localhost']['stdout'])
+
+        print(self._get_file(self.history[0],
+                             'work/logs/job-output.json'))
+        self.assertIn(token,
+                      self._get_file(self.history[0],
+                                     'work/logs/job-output.txt'))
+
+        log_output = output.getvalue()
+        self.assertIn('Final playbook failed', log_output)
+        self.assertIn('Failure test', log_output)
diff --git a/zuul/executor/server.py b/zuul/executor/server.py
index 459a554..b22be60 100644
--- a/zuul/executor/server.py
+++ b/zuul/executor/server.py
@@ -1229,8 +1229,36 @@
                 # precedence over the post result.
                 if not pre_failed:
                     result = 'POST_FAILURE'
+                if (index + 1) == len(self.jobdir.post_playbooks):
+                    self._logFinalPlaybookError()
+
         return result
 
+    def _logFinalPlaybookError(self):
+        # Failures in the final post playbook can include failures
+        # uploading logs, which makes diagnosing issues difficult.
+        # Grab the output from the last playbook from the json
+        # file and log it.
+        json_output = self.jobdir.job_output_file.replace('txt', 'json')
+        self.log.debug("Final playbook failed")
+        if not os.path.exists(json_output):
+            self.log.debug("JSON logfile {logfile} is missing".format(
+                logfile=json_output))
+            return
+        try:
+            output = json.load(open(json_output, 'r'))
+            last_playbook = output[-1]
+            # Transform json to yaml - because it's easier to read and given
+            # the size of the data it'll be extra-hard to read this as an
+            # all on one line stringified nested dict.
+            yaml_out = yaml.safe_dump(last_playbook, default_flow_style=False)
+            for line in yaml_out.split('\n'):
+                self.log.debug(line)
+        except Exception:
+            self.log.exception(
+                "Could not decode json from {logfile}".format(
+                    logfile=json_output))
+
     def getHostList(self, args):
         hosts = []
         for node in args['nodes']: