diff --git a/src/com/mirantis/mk/Ruby.groovy b/src/com/mirantis/mk/Ruby.groovy
index 1a093e5..512e671 100644
--- a/src/com/mirantis/mk/Ruby.groovy
+++ b/src/com/mirantis/mk/Ruby.groovy
@@ -9,11 +9,13 @@
  * @param rubyVersion target ruby version (optional, default 2.6.6)
  */
 def ensureRubyEnv(rubyVersion="2.6.6"){
-    if (!fileExists("/var/lib/jenkins/.rbenv/versions/${rubyVersion}/bin/ruby")){
-        //XXX: patch ruby-build because debian package is quite old
-        sh "rm -rf ~/.rbenv/plugins/ruby-build"
-        sh "git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build"
-        sh "rbenv install ${rubyVersion} -sv";
+    lock('install_ruby_system') {
+        if (!fileExists("/var/lib/jenkins/.rbenv/versions/${rubyVersion}/bin/ruby")){
+            //XXX: patch ruby-build because debian package is quite old
+            sh "rm -rf ~/.rbenv/plugins/ruby-build"
+            sh "git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build"
+            sh "rbenv install ${rubyVersion} -sv";
+        }
     }
     sh "rbenv local ${rubyVersion};rbenv exec gem update --system"
 }