diff --git a/opencontrail/meta/heka.yml b/opencontrail/meta/heka.yml
index 0667088..08f1937 100644
--- a/opencontrail/meta/heka.yml
+++ b/opencontrail/meta/heka.yml
@@ -22,7 +22,7 @@
         'contrail-svc-monitor',
         ) %}
     {%- if config.get('ifmap', {}).get('engine', 'irond') == 'irond' %}
-    {%- set control_processes += ('contrail-ifmap-server', 'contrail-irond',) %}
+      {%- set control_processes = control_processes + ('contrail-ifmap-server', 'contrail-irond',) %}
     {%- endif %}
   {%- endif %}
   {%- if database.get('enabled', False) %}
diff --git a/opencontrail/meta/prometheus.yml b/opencontrail/meta/prometheus.yml
index ab254af..b86be9f 100644
--- a/opencontrail/meta/prometheus.yml
+++ b/opencontrail/meta/prometheus.yml
@@ -49,7 +49,7 @@
     ) %}
 
     {%- if config.get('ifmap', {}).get('engine', 'irond') == 'irond' %}
-    {%- set control_processes += ('contrail-ifmap-server', 'contrail-irond',) %}
+      {%- set control_processes = control_processes + ('contrail-ifmap-server', 'contrail-irond',) %}
     {%- endif %}
 
     {%- for api in control_apis %}