Enable flagging a kubelet as a master node for tainting.

jobs/kubelet/spec

@@ -36,6 +36,9 @@ properties:
     description: The Kubelet will load its initial configuration from this.
       Omit this to use the built-in default configuration values.
       Command-line flags override configuration.
+  master:
+    description: The kubelet will label and taint itself as a master node with node-role.kubernetes.io/master=:NoSchedule
+    default: false
   kubectl-drain-timeout:
     description: "The length of time to wait before giving up draining a node, zero means infinite"
     default: "0s"

jobs/kubelet/templates/bin/post-start.erb

@@ -32,6 +32,10 @@ if timeout "$TIMEOUT" /var/vcap/jobs/kubelet/bin/ensure_kubelet_up_and_running
 then
   load_cached_containers
   node_name=$($kubectl get nodes -o wide -L bosh.id | grep "<%= spec.id %>$" | grep ' Ready' | awk '{print $1}')
+<% if p("master") %>
+  ${kubectl} label node ${node_name} node-role.kubernetes.io/master=
+  ${kubectl} taint nodes ${node_name} node-role.kubernetes.io/master=:NoSchedule
+<% end %>
   ${kubectl} uncordon ${node_name}
   ${kubectl} get nodes ${node_name} | grep -e ' Ready '
   echo "kubelet post-start checks succeeded"