diff --git a/ruby.yaml b/ruby.yaml
index 6eb9b97..1bfb38d 100644
--- a/ruby.yaml
+++ b/ruby.yaml
@@ -19,10 +19,9 @@ data:
     dependencies:
         - buildrequires:
             # platform: [] is recommended.
-            # But set "-f28" to avoid the build failure as a temporary workflow.
-            platform: [-f28]
+            platform: [-el8]
           requires:
-            platform: [-f28]
+            platform: [-el8]
     components:
         # SRPMs
         rpms:
@@ -75,6 +74,8 @@ data:
             macros: |
                 # To disable tests in several packages.
                 %_without_tests 1
+                # To avoid the test faiures by timeout in ruby.
+                %test_timeout_scale 6
     api:
         # RPMs
         # From *.spec %package