AMBARI-24670. Directory creation sometimes fails with parallel_execution=1

ambari-agent/src/test/python/resource_management/TestLinkResource.py

@@ -34,7 +34,7 @@ class TestLinkResource(TestCase):
 
   @patch.object(os.path, "realpath")
   @patch("resource_management.core.sudo.path_lexists")
-  @patch("resource_management.core.sudo.path_lexists")
+  @patch("resource_management.core.sudo.path_islink")
   @patch("resource_management.core.sudo.unlink")
   @patch("resource_management.core.sudo.symlink")
   def test_action_create_relink(self, symlink_mock, unlink_mock, 

ambari-common/src/main/python/resource_management/core/providers/system.py

@@ -172,7 +172,7 @@ def action_create(self):
       if self.resource.follow:
         # Follow symlink until the tail.
         followed_links = set()
-        while sudo.path_lexists(path):
+        while sudo.path_islink(path):
           if path in followed_links:
             raise Fail("Applying %s failed, looped symbolic links found while resolving %s" % (self.resource, path))
           followed_links.add(path)
@@ -188,8 +188,15 @@ def action_create(self):
         if not sudo.path_isdir(dirname):
           raise Fail("Applying %s failed, parent directory %s doesn't exist" % (self.resource, dirname))
 
-        sudo.makedir(path, self.resource.mode or 0755)
-
+        try:
+          sudo.makedir(path, self.resource.mode or 0755)
+        except Exception as ex:
+          # race condition (somebody created the file before us)
+          if "File exists" in str(ex):
+            sudo.makedirs(path, self.resource.mode or 0755)
+          else:
+            raise
+
     if not sudo.path_isdir(path):
       raise Fail("Applying %s failed, file %s already exists" % (self.resource, path))
 
@@ -216,7 +223,7 @@ def action_create(self):
       oldpath = os.path.realpath(path)
       if oldpath == self.resource.to:
         return
-      if not sudo.path_lexists(path):
+      if not sudo.path_islink(path):
         raise Fail(
           "%s trying to create a symlink with the same name as an existing file or directory" % self.resource)
       Logger.info("%s replacing old symlink to %s" % (self.resource, oldpath))

ambari-common/src/main/python/resource_management/core/source.py

@@ -72,7 +72,7 @@ def get_content(self):
       basedir = self.env.config.basedir
       path = os.path.join(basedir, "files", self.name)
 
-    if not sudo.path_isfile(path) and not sudo.path_lexists(path):
+    if not sudo.path_isfile(path):
       raise Fail("{0} Source file {1} is not found".format(repr(self), path))
 
     return self.read_file(path)

ambari-common/src/main/python/resource_management/core/sudo.py

@@ -159,7 +159,10 @@ def path_exists(path):
 
   def path_isdir(path):
     return os.path.isdir(path)
-
+
+  def path_islink(path):
+    return os.path.islink(path)
+
   def path_lexists(path):
     return os.path.lexists(path)
 
@@ -267,10 +270,14 @@ def path_exists(path):
   # os.path.isdir
   def path_isdir(path):
     return (shell.call(["test", "-d", path], sudo=True)[0] == 0)
+
+  # os.path.islink
+  def path_islink(path):
+    return (shell.call(["test", "-L", path], sudo=True)[0] == 0)
 
   # os.path.lexists
   def path_lexists(path):
-    return (shell.call(["test", "-L", path], sudo=True)[0] == 0)
+    return (shell.call(["test", "-e", path], sudo=True)[0] == 0)
 
   # os.readlink
   def readlink(path):