enable_fqdns_grains default to false on Windows

conf/minion

@@ -157,6 +157,16 @@
 # Set the directory used to hold unix sockets.
 #sock_dir: /var/run/salt/minion
 
+# In order to calculate the fqdns grain, all the IP addresses from the minion
+# are processed with underlying calls to `socket.gethostbyaddr` which can take
+# 5 seconds to be released (after reaching `socket.timeout`) when there is no
+# fqdn for that IP. These calls to `socket.gethostbyaddr` are processed
+# asynchronously, however, it still adds 5 seconds every time grains are
+# generated if an IP does not resolve. In Windows grains are regenerated each
+# time a new process is spawned. Therefore, the default for Windows is `False`.
+# All other OSes default to `True`
+# enable_fqdn_grains: True
+
 # The minion can take a while to start up when lspci and/or dmidecode is used
 # to populate the grains for the minion. Set this to False if you do not need
 # GPU hardware grains for your minion.

doc/ref/configuration/minion.rst

@@ -1053,6 +1053,26 @@ The directory where Unix sockets will be kept.
 
     sock_dir: /var/run/salt/minion
 
+.. conf_minion:: enable_fqdns_grains
+
+``enable_fqdns_grains``
+-----------------------
+
+Default: ``True``
+
+In order to calculate the fqdns grain, all the IP addresses from the minion are
+processed with underlying calls to ``socket.gethostbyaddr`` which can take 5 seconds
+to be released (after reaching ``socket.timeout``) when there is no fqdn for that IP.
+These calls to ``socket.gethostbyaddr`` are processed asynchronously, however, it still
+adds 5 seconds every time grains are generated if an IP does not resolve. In Windows
+grains are regenerated each time a new process is spawned. Therefore, the default for
+Windows is ``False``. All other OSes default to ``True``. This options was
+added `here <https://github.com/saltstack/salt/pull/55581>`_.
+
+.. code-block:: yaml
+
+    enable_fqdns_grains: False
+
 .. conf_minion:: enable_gpu_grains
 
 ``enable_gpu_grains``

salt/config/__init__.py

@@ -66,12 +66,14 @@ if salt.utils.platform.is_windows():
     # support in ZeroMQ, we want the default to be something that has a
     # chance of working.
     _DFLT_IPC_MODE = "tcp"
+    _DFLT_FQDNS_GRAINS = False
     _MASTER_TRIES = -1
     # This needs to be SYSTEM in order for salt-master to run as a Service
     # Otherwise, it will not respond to CLI calls
     _MASTER_USER = "SYSTEM"
 else:
     _DFLT_IPC_MODE = "ipc"
+    _DFLT_FQDNS_GRAINS = True
     _MASTER_TRIES = 1
     _MASTER_USER = salt.utils.user.get_user()
 
@@ -352,6 +354,8 @@ VALID_OPTS = immutabletypes.freeze(
         "test": bool,
         # Tell the loader to attempt to import *.pyx cython files if cython is available
         "cython_enable": bool,
+        # Whether or not to load grains for FQDNs
+        "enable_fqdns_grains": bool,
         # Whether or not to load grains for the GPU
         "enable_gpu_grains": bool,
         # Tell the loader to attempt to import *.zip archives
@@ -1133,6 +1137,7 @@ DEFAULT_MINION_OPTS = immutabletypes.freeze(
         "test": False,
         "ext_job_cache": "",
         "cython_enable": False,
+        "enable_fqdns_grains": _DFLT_FQDNS_GRAINS,
         "enable_gpu_grains": True,
         "enable_zip_modules": False,
         "state_verbose": True,

salt/grains/core.py

@@ -2352,7 +2352,7 @@ def fqdns():
     # Provides:
     # fqdns
     opt = {"fqdns": []}
-    if __opts__.get("enable_fqdns_grains", True):
+    if __opts__.get("enable_fqdns_grains", False if salt.utils.platform.is_windows() else True):
         opt = __salt__["network.fqdns"]()
     return opt