Fix kubelet systemd unit

Use ansible systemd built-ins instead of customized presets

Change-Id: I849dbeba4fbeb7f5ecf44b26823c341a12eebad7

image-builder/assets/playbooks/roles/osconfig/tasks/kubernetes.yaml

@@ -3,13 +3,8 @@
     src: kubelet.service.j2
     dest: "/etc/systemd/system/kubelet.service.d/10-kubeadm.conf"
     mode: 0644
-- name: "Kubernetes | Ensuring systemd preset directory exists"
-  file:
-    path: "/etc/systemd/system-preset"
-    state: directory
-    mode: '0755'
-# Started instead by cloud-init run commands
-- name: "Kubernetes | Dont enable kubelet unit by default"
-  copy:
-    content: 'disable kubelet.service'
-    dest: /etc/systemd/system-preset/00-kubelet.preset
+- name: "Kubernetes | configuring kubelet systemd unit"
+  systemd:
+    name: "kubelet.service"
+    enabled: no
+    force: no

image-builder/assets/playbooks/roles/osconfig/templates/kubelet.service.j2

@@ -14,6 +14,7 @@ EnvironmentFile=-/etc/default/kubelet
 {% for arg in kubelet.extra_systemd_args %}
 {% set ns.content = ns.content + ' --' + arg.name + '=' + arg.value %}
 {% endfor %}
+ExecStart=
 ExecStart=/usr/bin/kubelet $KUBELET_KUBECONFIG_ARGS $KUBELET_CONFIG_ARGS $KUBELET_KUBEADM_ARGS $KUBELET_EXTRA_ARGS {{ ns.content }}
 CPUAffinity=
 Restart=always