ansible: handle mount of /sys the same way IPA does it

* Mount with -t sysfs instead of a bind mount
* Retry umounting of each directory several times.

I'm seeing occasional failures unmounting /sys, as it's still busy.
This patch should fix it.

Change-Id: I4bc6dfd6939699f7a4ed7cc59e2e503b46bbaeaf

ironic/drivers/modules/ansible/playbooks/roles/configure/defaults/main.yaml

@@ -1 +1,3 @@
 tmp_rootfs_mount: /tmp/rootfs
+umount_retry_count: 5
+umount_retry_delay: 3

ironic/drivers/modules/ansible/playbooks/roles/configure/tasks/grub.yaml

@@ -48,9 +48,12 @@
   command: mount -o bind /{{ item }} {{ tmp_rootfs_mount }}/{{ item }}
   with_items:
     - dev
-    - sys
     - proc
 
+- name: mount /sys for chroot
+  become: yes
+  command: mount -t sysfs sysfs {{ tmp_rootfs_mount }}/sys
+
 - block:
   - name: get grub version string
     become: yes
@@ -70,10 +73,14 @@
     become: yes
     command: chroot {{ tmp_rootfs_mount }} /bin/sh -c '{{ grub_config_cmd }} -o {{ grub_config_file }}'
   always:
-  - name: unmount dirs for chroot
+  - name: unmount /{{ item }} for chroot
     become: yes
     command: umount {{ tmp_rootfs_mount }}/{{ item }}
+    register: task_result
+    retries: '{{ umount_retry_count }}'
+    delay: '{{ umount_retry_delay }}'
+    until: task_result.rc == 0
     with_items:
-      - dev
       - sys
       - proc
+      - dev