Add options for configuring control plane component extra volumes (#3779)

This takes care of a few arbitrary use cases that may require custom mounts
inside of apiserver, controller manager, or scheduler.

roles/kubernetes/master/defaults/main.yml

@@ -129,6 +129,17 @@ kube_kubeadm_apiserver_extra_args: {}
 kube_kubeadm_controller_extra_args: {}
 kube_kubeadm_scheduler_extra_args: {}
 
+## Extra control plane host volume mounts
+## Example:
+#apiserver_extra_volumes:
+#  - name: name
+#    hostPath: /host/path
+#    mountPath: /mount/path
+#    writable: false
+apiserver_extra_volumes: {}
+controller_manager_extra_volumes: {}
+scheduler_extra_volumes: {}
+
 ## Encrypting Secret Data at Rest
 kube_encrypt_secret_data: false
 kube_encrypt_token: "{{ lookup('password', credentials_dir + '/kube_encrypt_token.creds length=32 chars=ascii_letters,digits') }}"