diff --git a/sahara/service/coordinator.py b/sahara/service/coordinator.py
index 282de87bea..c03179ce7b 100644
--- a/sahara/service/coordinator.py
+++ b/sahara/service/coordinator.py
@@ -100,7 +100,8 @@ class HashRing(Coordinator):
 
     @staticmethod
     def _hash(key):
-        return int(hashlib.md5(str(key)).hexdigest(), 16)  # nosec
+        return int(
+            hashlib.md5(str(key).encode('utf-8')).hexdigest(), 16)  # nosec
 
     def _build_ring(self):
         ring = {}
diff --git a/sahara/service/validations/edp/job_binary_internal.py b/sahara/service/validations/edp/job_binary_internal.py
index 9587bff96d..a92e3be69e 100644
--- a/sahara/service/validations/edp/job_binary_internal.py
+++ b/sahara/service/validations/edp/job_binary_internal.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 from oslo_config import cfg
+import six
 
 import sahara.exceptions as e
 from sahara.i18n import _
@@ -31,7 +32,7 @@ def check_job_binary_internal(data, **kwargs):
     if not is_internal_db_enabled():
         raise e.BadJobBinaryInternalException(
             _("Sahara internal db is disabled for storing job binaries."))
-    if not (type(data) is str and len(data) > 0):
+    if not (isinstance(data, six.string_types) and len(data) > 0):
         raise e.BadJobBinaryInternalException()
     if "name" in kwargs:
         name = kwargs["name"]
diff --git a/sahara/utils/api.py b/sahara/utils/api.py
index 847264fceb..2fbe5fb917 100644
--- a/sahara/utils/api.py
+++ b/sahara/utils/api.py
@@ -18,6 +18,7 @@ import traceback
 import flask
 from oslo_log import log as logging
 from oslo_middleware import request_id as oslo_req_id
+import six
 from werkzeug import datastructures
 
 from sahara import context
@@ -53,7 +54,7 @@ class Rest(flask.Blueprint):
         return self._mroute('PATCH', rule, status_code)
 
     def _mroute(self, methods, rule, status_code=None, **kw):
-        if type(methods) is str:
+        if isinstance(methods, six.string_types):
             methods = [methods]
         return self.route(rule, methods=methods, status_code=status_code, **kw)