diff --git a/autotools/build-bash-completion b/autotools/build-bash-completion
index 56204af00111eaf69e48ff25250af10e608d6553..79258c2cc2b1e9f9e0a9a463182053599a169355 100755
--- a/autotools/build-bash-completion
+++ b/autotools/build-bash-completion
@@ -312,6 +312,10 @@ class CompletionWriter:
       # Only static choices implemented so far (e.g. no node list)
       suggest = getattr(opt, "completion_suggest", None)
 
+      # our custom option type
+      if opt.type == "bool":
+        suggest = ["yes", "no"]
+
       if not suggest:
         suggest = opt.choices
 
diff --git a/lib/cli.py b/lib/cli.py
index 9c480d67ad6a4f9dce3183b6c8de1f5fe77a8f90..5df4aaeca00c6f7964709a7980420a3213bfb5f3 100644
--- a/lib/cli.py
+++ b/lib/cli.py
@@ -457,6 +457,21 @@ def check_key_val(option, opt, value):  # pylint: disable-msg=W0613
   return _SplitKeyVal(opt, value)
 
 
+def check_bool(option, opt, value): # pylint: disable-msg=W0613
+  """Custom parser for yes/no options.
+
+  This will store the parsed value as either True or False.
+
+  """
+  value = value.lower()
+  if value == constants.VALUE_FALSE or value == "no":
+    return False
+  elif value == constants.VALUE_TRUE or value == "yes":
+    return True
+  else:
+    raise errors.ParameterError("Invalid boolean value '%s'" % value)
+
+
 # completion_suggestion is normally a list. Using numeric values not evaluating
 # to False for dynamic completion.
 (OPT_COMPL_MANY_NODES,
@@ -487,18 +502,19 @@ class CliOption(Option):
     "identkeyval",
     "keyval",
     "unit",
+    "bool",
     )
   TYPE_CHECKER = Option.TYPE_CHECKER.copy()
   TYPE_CHECKER["identkeyval"] = check_ident_key_val
   TYPE_CHECKER["keyval"] = check_key_val
   TYPE_CHECKER["unit"] = check_unit
+  TYPE_CHECKER["bool"] = check_bool
 
 
 # optparse.py sets make_option, so we do it for our own option class, too
 cli_option = CliOption
 
 
-_YESNO = ("yes", "no")
 _YORNO = "yes|no"
 
 DEBUG_OPT = cli_option("-d", "--debug", default=0, action="count",
@@ -759,19 +775,19 @@ NOSSH_KEYCHECK_OPT = cli_option("--no-ssh-key-check", dest="ssh_key_check",
 
 
 MC_OPT = cli_option("-C", "--master-candidate", dest="master_candidate",
-                    choices=_YESNO, default=None, metavar=_YORNO,
+                    type="bool", default=None, metavar=_YORNO,
                     help="Set the master_candidate flag on the node")
 
 OFFLINE_OPT = cli_option("-O", "--offline", dest="offline", metavar=_YORNO,
-                         choices=_YESNO, default=None,
+                         type="bool", default=None,
                          help="Set the offline flag on the node")
 
 DRAINED_OPT = cli_option("-D", "--drained", dest="drained", metavar=_YORNO,
-                         choices=_YESNO, default=None,
+                         type="bool", default=None,
                          help="Set the drained flag on the node")
 
 ALLOCATABLE_OPT = cli_option("--allocatable", dest="allocatable",
-                             choices=_YESNO, default=None, metavar=_YORNO,
+                             type="bool", default=None, metavar=_YORNO,
                              help="Set the allocatable flag on a volume")
 
 NOLVM_STORAGE_OPT = cli_option("--no-lvm-storage", dest="lvm_storage",
diff --git a/scripts/gnt-node b/scripts/gnt-node
index 5c985619ec93b30ea7103b38df04e92508c86828..61c4f271488fd78b93495a6b5f8ed5eaf9371099 100755
--- a/scripts/gnt-node
+++ b/scripts/gnt-node
@@ -571,7 +571,7 @@ def ModifyStorage(opts, args):
   changes = {}
 
   if opts.allocatable is not None:
-    changes[constants.SF_ALLOCATABLE] = (opts.allocatable == "yes")
+    changes[constants.SF_ALLOCATABLE] = opts.allocatable
 
   if changes:
     op = opcodes.OpModifyNodeStorage(node_name=node_name,
@@ -618,23 +618,10 @@ def SetNodeParams(opts, args):
     ToStderr("Please give at least one of the parameters.")
     return 1
 
-  if opts.master_candidate is not None:
-    candidate = opts.master_candidate == 'yes'
-  else:
-    candidate = None
-  if opts.offline is not None:
-    offline = opts.offline == 'yes'
-  else:
-    offline = None
-
-  if opts.drained is not None:
-    drained = opts.drained == 'yes'
-  else:
-    drained = None
   op = opcodes.OpSetNodeParams(node_name=args[0],
-                               master_candidate=candidate,
-                               offline=offline,
-                               drained=drained,
+                               master_candidate=opts.master_candidate,
+                               offline=opts.offline,
+                               drained=opts.drained,
                                force=opts.force,
                                auto_promote=opts.auto_promote)