diff --git a/ipaserver/install/installutils.py b/ipaserver/install/installutils.py
index 6a7a19b31..fbec40efa 100644
--- a/ipaserver/install/installutils.py
+++ b/ipaserver/install/installutils.py
@@ -565,11 +565,15 @@ def set_directive_lines(quotes, separator, k, v, lines, comment):
         v_quoted = quote_directive_value(v, '"') if quotes else v
         new_line = ''.join([k, separator, v_quoted, '\n'])
 
+    # Special case: consider space as "white space" so tabs are allowed
+    if separator == ' ':
+        separator = '[ \t]+'
+
     found = False
     addnext = False  # add on next line, found a comment
-    matcher = re.compile(r'\s*{}'.format(re.escape(k + separator)))
-    cmatcher = re.compile(r'\s*{}\s*{}'.format(comment,
-                                               re.escape(k + separator)))
+    matcher = re.compile(r'\s*{}\s*{}'.format(re.escape(k), separator))
+    cmatcher = re.compile(r'\s*{}\s*{}\s*{}'.format(comment,
+                                                    re.escape(k), separator))
     for line in lines:
         if matcher.match(line):
             found = True
diff --git a/ipatests/test_ipaserver/test_install/test_installutils.py b/ipatests/test_ipaserver/test_install/test_installutils.py
index 66b4585dd..0a426fe63 100644
--- a/ipatests/test_ipaserver/test_install/test_installutils.py
+++ b/ipatests/test_ipaserver/test_install/test_installutils.py
@@ -15,6 +15,11 @@ EXAMPLE_CONFIG = [
     'foobar=2\n',
 ]
 
+WHITESPACE_CONFIG = [
+    'foo 1\n',
+    'foobar\t2\n',
+]
+
 
 @pytest.fixture
 def tempdir(request):
@@ -44,6 +49,28 @@ class test_set_directive_lines(object):
         assert list(lines) == ['foo=3\n', 'foobar=2\n']
 
 
+class test_set_directive_lines_whitespace(object):
+    def test_remove_directive(self):
+        lines = installutils.set_directive_lines(
+            False, ' ', 'foo', None, WHITESPACE_CONFIG, comment="#")
+        assert list(lines) == ['foobar\t2\n']
+
+    def test_add_directive(self):
+        lines = installutils.set_directive_lines(
+            False, ' ', 'baz', '4', WHITESPACE_CONFIG, comment="#")
+        assert list(lines) == ['foo 1\n', 'foobar\t2\n', 'baz 4\n']
+
+    def test_set_directive_does_not_clobber_suffix_key(self):
+        lines = installutils.set_directive_lines(
+            False, ' ', 'foo', '3', WHITESPACE_CONFIG, comment="#")
+        assert list(lines) == ['foo 3\n', 'foobar\t2\n']
+
+    def test_set_directive_with_tab(self):
+        lines = installutils.set_directive_lines(
+            False, ' ', 'foobar', '6', WHITESPACE_CONFIG, comment="#")
+        assert list(lines) == ['foo 1\n', 'foobar 6\n']
+
+
 class test_set_directive(object):
     def test_set_directive(self):
         """Check that set_directive writes the new data and preserves mode."""