diff --git a/gating-pipeline.groovy b/gating-pipeline.groovy
index aeaee9a..15518d4 100644
--- a/gating-pipeline.groovy
+++ b/gating-pipeline.groovy
@@ -4,6 +4,7 @@
  * JOBS_NAMESPACE - Gerrit gating jobs namespace (mk, contrail, ...)
  *
  **/
+import groovy.json.JsonOutput
 
 def common = new com.mirantis.mk.Common()
 def gerrit = new com.mirantis.mk.Gerrit()
@@ -18,12 +19,7 @@
 }
 
 def callJobWithExtraVars(String jobName) {
-    def gerritVars = '\n---'
-    for (envVar in env.getEnvironment()) {
-        if (envVar.key.startsWith("GERRIT_")) {
-            gerritVars += "\n${envVar.key}: '${envVar.value}'"
-        }
-    }
+    def gerritVars = JsonOutput.toJson(env.getEnvironment().findAll{ it.key.startsWith('GERRIT_') })
     testJob = build job: jobName, parameters: [
         [$class: 'TextParameterValue', name: 'EXTRA_VARIABLES_YAML', value: gerritVars]
     ]
diff --git a/test-system-reclass-pipeline.groovy b/test-system-reclass-pipeline.groovy
index 04eafeb..a8e10b7 100644
--- a/test-system-reclass-pipeline.groovy
+++ b/test-system-reclass-pipeline.groovy
@@ -1,3 +1,5 @@
+import groovy.json.JsonOutput
+
 def gerrit = new com.mirantis.mk.Gerrit()
 def common = new com.mirantis.mk.Common()
 
@@ -7,12 +9,7 @@
 if (extraVarsYaml != '') {
     common.mergeEnv(env, extraVarsYaml)
 } else {
-    extraVarsYaml = '\n---'
-    for (envVar in env.getEnvironment()) {
-        if (envVar.key.startsWith("GERRIT_")) {
-            extraVarsYaml += "\n${envVar.key}: '${envVar.value}'"
-        }
-    }
+    extraVarsYaml = JsonOutput.toJson(env.getEnvironment().findAll{ it.key.startsWith('GERRIT_') })
 }
 
 def slaveNode = env.SLAVE_NODE ?: 'python&&docker'