Control the collection of lvm grains via config

lvm grain collection can take a long time on systems with a lot of
volumes and volume groups. On one server we measured ~3 minutes, which
is way too long for grains.

This change is backwards-compatible, leaving the lvm grain collection
enabled by default. Users with a lot of lvm volumes/volume groups can
disable these grains in the minion config by adding "lvm" to
disabled_grains:

disabled_grains:
   ...
   - lvm

changelog/63114.added.md

@@ -0,0 +1 @@
+Control the collection of lvm grains via disabled_grains.

salt/grains/lvm.py

@@ -1,5 +1,14 @@
 """
 Detect LVM Volumes
+
+.. versionchanged:: 3008.0
+
+To disable these grains add "lvm" to "disabled_grains" in the minion config.
+
+.. code-block:: yaml
+
+    disabled_grains:
+      - lvm
 """
 
 import logging
@@ -16,6 +25,12 @@
 
 log = logging.getLogger(__name__)
 
+__virtualname__ = "lvm"
+
+
+def __virtual__():
+    return __virtualname__ not in __opts__.get("disabled_grains", [])
+
 
 def lvm():
     """
@@ -33,14 +48,12 @@ def _linux_lvm():
     ret = {}
     cmd = salt.utils.path.which("lvm")
     if cmd:
-        vgs = __salt__["cmd.run_all"]("{} vgs -o vg_name --noheadings".format(cmd))
+        vgs = __salt__["cmd.run_all"](f"{cmd} vgs -o vg_name --noheadings")
 
         for vg in vgs["stdout"].splitlines():
             vg = vg.strip()
             ret[vg] = []
-            lvs = __salt__["cmd.run_all"](
-                "{} lvs -o lv_name --noheadings {}".format(cmd, vg)
-            )
+            lvs = __salt__["cmd.run_all"](f"{cmd} lvs -o lv_name --noheadings {vg}")
             for lv in lvs["stdout"].splitlines():
                 ret[vg].append(lv.strip())
 
@@ -52,11 +65,11 @@ def _linux_lvm():
 def _aix_lvm():
     ret = {}
     cmd = salt.utils.path.which("lsvg")
-    vgs = __salt__["cmd.run"]("{}".format(cmd))
+    vgs = __salt__["cmd.run"](f"{cmd}")
 
     for vg in vgs.splitlines():
         ret[vg] = []
-        lvs = __salt__["cmd.run"]("{} -l {}".format(cmd, vg))
+        lvs = __salt__["cmd.run"](f"{cmd} -l {vg}")
         for lvline in lvs.splitlines()[2:]:
             lv = lvline.split(" ", 1)[0]
             ret[vg].append(lv)