Add option to disable automatic write of sysfs attributes

Fixes: PROD-23149 (PROD:23149)

Change-Id: I14c68a0a519a63951571f966fae72fd01ec2e556

README.rst

@@ -805,6 +805,22 @@ Optional: You can also use list that will ensure order of items.
                 power/state: "root:power"
             - devices/system/cpu/cpu0/cpufreq/scaling_governor: powersave
 
+Sysfs definition with disabled automatic write. Attributes are saved
+to configuration, but are not applied during the run.
+Thay will be applied automatically after the reboot.
+
+
+.. code-block:: yaml
+
+    linux:
+      system:
+        sysfs:
+          enable_apply: false
+          scheduler:
+            block/sda/queue/scheduler: deadline
+
+.. note:: The `enable_apply` parameter defaults to `True` if not defined.
+
 Huge Pages
 ~~~~~~~~~~~~
 

linux/system/sysfs.sls

@@ -11,6 +11,8 @@ linux_sysfs_package:
     - require:
       - pkg: linux_sysfs_package
 
+{% set apply = system.get('sysfs', {}).pop('enable_apply', True) %}
+
 {%- for name, sysfs in system.get('sysfs', {}).items() %}
 
 /etc/sysfs.d/{{ name }}.conf:
@@ -32,6 +34,8 @@ linux_sysfs_package:
 {%- set sysfs_list = sysfs %}
 {%- endif %}
 
+{%- if apply %}
+
 {%- for item in sysfs_list %}
 {%- set list_idx = loop.index %}
 {%- for key, value in item.items() %}
@@ -48,4 +52,7 @@ linux_sysfs_write_{{ list_idx }}_{{ name }}_{{ key }}:
   {%- endfor %}
 
 {%- endfor %}
+
+{%- endif %}
+
 {%- endfor %}

tests/pillar/system.sls

@@ -99,6 +99,7 @@ linux:
             subjects:
             - '@group1'
     sysfs:
+      enable_apply: true
       scheduler:
         block/sda/queue/scheduler: deadline
       power: