Only add admission plugins if defined

roles/kubernetes/master/defaults/main.yml

@@ -41,7 +41,7 @@ kube_apiserver_cpu_limit: 800m
 kube_apiserver_memory_requests: 256M
 kube_apiserver_cpu_requests: 100m
 
-# Admission control plug-ins
+# 1.9 and below Admission control plug-ins
 kube_apiserver_admission_control:
   - Initializers
   - NamespaceLifecycle

roles/kubernetes/master/templates/kubeadm-config.yaml.j2

@@ -37,8 +37,12 @@ apiServerExtraArgs:
 {% if kube_version | version_compare('v1.10', '<') %}
   admission-control: {{ kube_apiserver_admission_control | join(',') }}
 {% else %}
+{% if kube_apiserver_enable_admission_plugins|length > 0 %}
   enable-admission-plugins: {{ kube_apiserver_enable_admission_plugins | join(',') }} 
+{% endif %}
+{% if kube_apiserver_disable_admission_plugins|length > 0 %}
   disable-admission-plugins: {{ kube_apiserver_disable_admission_plugins | join(',') }} 
+{% endif %}
 {% endif %}
   apiserver-count: "{{ kube_apiserver_count }}"
 {% if kube_version | version_compare('v1.9', '>=') %}

roles/kubernetes/master/templates/manifests/kube-apiserver.manifest.j2

@@ -48,8 +48,12 @@ spec:
 {% if kube_version | version_compare('v1.10', '<') %}
     - --admission-control={{ kube_apiserver_admission_control | join(',') }}
 {% else %}
+{% if kube_apiserver_enable_admission_plugins|length > 0 %}
     - --enable-admission-plugins={{ kube_apiserver_enable_admission_plugins | join(',') }} 
+{% endif %}
+{% if kube_apiserver_disable_admission_plugins|length > 0 %}
     - --disable-admission-plugins={{ kube_apiserver_disable_admission_plugins | join(',') }} 
+{% endif %}
 {% endif %}
     - --service-cluster-ip-range={{ kube_service_addresses }}
     - --service-node-port-range={{ kube_apiserver_node_port_range }}