Move PostgreSQL data directory if init had failed.

Prevent treating the incompletely-initialized PostgreSQL cluster
as a valid on restart by forcefully moving the data directory.
I don't want to remove it altogether, since a DBA might decide
to analyze the failed PG cluster in order to resolve the init
issue.

patroni/__init__.py

@@ -46,6 +46,8 @@ class Patroni:
         """ cleanup the DCS if initialization was not successfull """
         logger.info("removing initialize key after failed attempt to initialize the cluster")
         self.ha.dcs.cancel_initialization()
+        self.postgresql.stop()
+        self.postgresql.move_data_directory()
 
     def initialize(self):
         # wait for etcd to be available

patroni/postgresql.py

@@ -4,6 +4,7 @@ import psycopg2
 import shlex
 import shutil
 import subprocess
+import time
 
 from patroni.utils import sleep
 from six.moves.urllib_parse import urlparse
@@ -159,7 +160,7 @@ class Postgresql:
         return ret
 
     def is_running(self):
-        return subprocess.call(' '.join(self._pg_ctl) + ' status > /dev/null', shell=True) == 0
+        return subprocess.call(' '.join(self._pg_ctl) + ' status > /dev/null 2>&1', shell=True) == 0
 
     def call_nowait(self, cb_name, is_leader=None):
         """ pick a callback command and call it without waiting for it to finish """
@@ -415,3 +416,9 @@ recovery_target_timeline = 'latest'
                 self.write_recovery_conf(current_leader)
                 ret = self.start()
         return ret
+
+    def move_data_directory(self):
+        if os.path.isdir(self.data_dir) and not self.is_running():
+            os.rename(self.data_dir, '{0}_{1}'.format(self.data_dir, str(long(time.time()))))
+            return True
+        return False