[pike] Allow to set ionice level for lvm volume clear

for now implemented in downstream

pillar item is compute.lvm.volume_clear_ionice_level

This is followup to I3d00e1b4c8752133ef395797045c3f2a3afae94d
enabiling this feature in Pike too.

Change-Id: Id93693eb59cdbad79ff0ea67e7864ea380b08da2
Related-Issue: PROD-30537
diff --git a/nova/files/pike/nova-compute.conf.Debian b/nova/files/pike/nova-compute.conf.Debian
index 270510b..85749a8 100644
--- a/nova/files/pike/nova-compute.conf.Debian
+++ b/nova/files/pike/nova-compute.conf.Debian
@@ -6054,6 +6054,9 @@
 {%- if compute.lvm.volume_clear_size is defined %}
 volume_clear_size={{ compute.lvm.volume_clear_size }}
 {%- endif %}
+{%- if compute.lvm.volume_clear_ionice_level is defined %}
+volume_clear_ionice_level={{compute.lvm.volume_clear_ionice_level}}
+{%- endif %}
 {%- endif %}
 
 # The ID of the image to boot from to rescue data from a corrupted instance.
@@ -6724,6 +6727,31 @@
 #volume_clear_size=0
 
 #
+# What I/O schedule class and priority level should be used when clearing
+# a volume. Only takes effect if ``volume_clear`` option is set to ``zero`` or
+# ``shred``. For more info about classes and priorities, check ``man ionice``.
+#
+# Possible values:
+#
+# * idle - use the Idle scheduling class. This option impacts system performance
+#   the least with a downside of increased time for volume clearance
+#   * from 0 to 7 - use the Best-effort scheduling class and set the priority level
+#     to the specified number
+#
+#     If not set - do not set I/O scheduling class explicitly. Usually, it's the most
+#     aggressive option in terms of system performance impact.
+#
+#     Related options:
+#
+#     * images_type - must be set to ``lvm``
+#     * volume_clear - must be set and the value must be different than ``none``
+#       for this option to have any impact
+#  (string value)
+# Possible values:
+# 'idle', '0', '1', '2', '3', '4', '5', '6', '7'
+#volume_clear_ionice_level=None
+
+#
 # Enable snapshot compression for ``qcow2`` images.
 #
 # Note: you can set ``snapshot_image_format`` to ``qcow2`` to force all
diff --git a/nova/files/pike/nova-controller.conf.Debian b/nova/files/pike/nova-controller.conf.Debian
index a73630b..92b8bdf 100644
--- a/nova/files/pike/nova-controller.conf.Debian
+++ b/nova/files/pike/nova-controller.conf.Debian
@@ -6693,6 +6693,30 @@
 #volume_clear_size=0
 
 #
+# What I/O schedule class and priority level should be used when clearing
+# a volume. Only takes effect if ``volume_clear`` option is set to ``zero`` or
+# ``shred``. For more info about classes and priorities, check ``man ionice``.
+#
+# Possible values:
+#
+# * idle - use the Idle scheduling class. This option impacts system performance
+#   the least with a downside of increased time for volume clearance
+#   * from 0 to 7 - use the Best-effort scheduling class and set the priority level
+#     to the specified number
+#
+#     If not set - do not set I/O scheduling class explicitly. Usually, it's the most
+#     aggressive option in terms of system performance impact.
+#
+#     Related options:
+#
+#     * images_type - must be set to ``lvm``
+#     * volume_clear - must be set and the value must be different than ``none``
+#       for this option to have any impact
+#  (string value)
+# Possible values:
+# 'idle', '0', '1', '2', '3', '4', '5', '6', '7'
+#volume_clear_ionice_level=None
+#
 # Enable snapshot compression for ``qcow2`` images.
 #
 # Note: you can set ``snapshot_image_format`` to ``qcow2`` to force all
diff --git a/nova/files/queens/nova-compute.conf.Debian b/nova/files/queens/nova-compute.conf.Debian
index b2cf195..86831ab 100644
--- a/nova/files/queens/nova-compute.conf.Debian
+++ b/nova/files/queens/nova-compute.conf.Debian
@@ -7265,19 +7265,19 @@
 # What I/O schedule class and priority level should be used when clearing
 # a volume. Only takes effect if ``volume_clear`` option is set to ``zero`` or
 # ``shred``. For more info about classes and priorities, check ``man ionice``.
-# 
+#
 # Possible values:
-# 
+#
 # * idle - use the Idle scheduling class. This option impacts system performance
 #   the least with a downside of increased time for volume clearance
 #   * from 0 to 7 - use the Best-effort scheduling class and set the priority level
 #     to the specified number
-# 
+#
 #     If not set - do not set I/O scheduling class explicitly. Usually, it's the most
 #     aggressive option in terms of system performance impact.
-# 
+#
 #     Related options:
-# 
+#
 #     * images_type - must be set to ``lvm``
 #     * volume_clear - must be set and the value must be different than ``none``
 #       for this option to have any impact