diff --git a/cdist/preos.py b/cdist/preos.py
index 378071db..491338d2 100644
--- a/cdist/preos.py
+++ b/cdist/preos.py
@@ -5,8 +5,9 @@ import inspect
 import argparse
 import cdist
 import logging
-import re
 import cdist.argparse
+import cdist.configuration
+import cdist.exec.util as util
 
 
 _PREOS_CALL = "commandline"
@@ -24,16 +25,6 @@ def extend_plugins_path(dirs):
             _PLUGINS_PATH.append(preos_dir)
 
 
-cdist_home = cdist.home_dir()
-if cdist_home:
-    extend_plugins_path((cdist_home, ))
-x = 'CDIST_PATH'
-if x in os.environ:
-    vals = re.split(r'(?<!\\):', os.environ[x])
-    vals = [x for x in vals if x]
-    extend_plugins_path(vals)
-
-
 def preos_plugin(obj):
     """It is preos if _PREOS_MARKER is True and has _PREOS_CALL."""
     if hasattr(obj, _PREOS_MARKER):
@@ -102,6 +93,9 @@ class PreOS(object):
                             help=('Add configuration directory (one that '
                                   'contains "preos" subdirectory)'),
                             action='append')
+        parser.add_argument('-g', '--config-file',
+                            help='Use specified custom configuration file.',
+                            dest="config_file", required=False)
         parser.add_argument('-L', '--list-preoses',
                             help='List available PreOS-es',
                             action='store_true', default=False)
@@ -110,8 +104,12 @@ class PreOS(object):
         cdist.argparse.handle_loglevel(args)
         log.debug("preos args : {}".format(args))
 
-        if args.conf_dir:
-            extend_plugins_path(args.conf_dir)
+        cfg = cdist.configuration.Configuration(args)
+        configuration = cfg.get_config(section='GLOBAL')
+        conf_dirs = util.resolve_conf_dirs(configuration,
+                                           args.conf_dir)
+
+        extend_plugins_path(conf_dirs)
         sys.path.extend(_PLUGINS_PATH)
         cls.preoses = find_preoses()
 
diff --git a/docs/changelog b/docs/changelog
index a7bcf9b1..1b1a909e 100644
--- a/docs/changelog
+++ b/docs/changelog
@@ -3,6 +3,7 @@ Changelog
 
 next:
 	* Type __acl: Add --entry parameter to replace --acl, deprecate --acl (Ander Punnar)
+	* Core: preos: Fix missing configuration file usage, support -g, --config-file option (Darko Poljak)
 
 6.4.0: 2020-01-04
 	* Type __consul_agent: Don't deploy init script on Alpine anymore, it ships with one itself (Nico Schottelius)
diff --git a/docs/src/man1/cdist.rst b/docs/src/man1/cdist.rst
index bc73a0b8..38248821 100644
--- a/docs/src/man1/cdist.rst
+++ b/docs/src/man1/cdist.rst
@@ -59,7 +59,9 @@ SYNOPSIS
                          [-I INVENTORY_DIR] [-a] [-f HOSTFILE] [-H] [-t]
                          [host [host ...]]
 
-    cdist preos [-h] [-l LOGLEVEL] [-q] [-v] [-c CONF_DIR] [-L] [preos] ...
+    cdist preos [-h] [-l LOGLEVEL] [-q] [-v] [-c CONF_DIR] [-g CONFIG_FILE]
+                [-L]
+                [preos] ...
 
     cdist preos [preos-options] debian [-h] [-l LOGLEVEL] [-q] [-v] [-b] [-a ARCH] [-B]
                                        [-C] [-c CDIST_PARAMS] [-D DRIVE] [-e REMOTE_EXEC]
@@ -464,6 +466,9 @@ Create PreOS.
 **-c CONF_DIR, --conf-dir CONF_DIR**
     Add configuration directory (one that contains "preos" subdirectory).
 
+**-g CONFIG_FILE, --config-file CONFIG_FILE**
+    Use specified custom configuration file.
+
 **-L, --list-preoses**
     List available PreOS-es.