diff --git a/cfg_checker/modules/reclass/comparer.py b/cfg_checker/modules/reclass/comparer.py
new file mode 100644
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+++ b/cfg_checker/modules/reclass/comparer.py
@@ -0,0 +1,364 @@
+"""Model Comparer:
+- yaml parser
+- class tree comparison
+"""
+import itertools
+import os
+import yaml
+
+from cfg_checker import reporter
+from cfg_checker.common import logger, logger_cli
+
+
+def get_element(element_path, input_data):     
+    paths = element_path.split(":")
+    data = input_data
+    for i in range(0, len(paths)):
+        data = data[paths[i]]
+    return data
+
+
+def pop_element(element_path, input_data):     
+    paths = element_path.split(":")
+    data = input_data
+    # Search for last dict
+    for i in range(0, len(paths)-1):
+        data = data[paths[i]]
+    # pop the actual element
+    return data.pop(paths[-1])
+
+
+class ModelComparer(object):
+    """Collection of functions to compare model data.
+    """
+    # key order is important
+    _model_parts = {
+        "01_nodes": "nodes",
+        "02_system": "classes:system",
+        "03_cluster": "classes:cluster",
+        "04_other": "classes"
+    }
+    
+    models = {}
+    models_path = "/srv/salt/reclass"
+    model_name_1 = "source"
+    model_path_1 = os.path.join(models_path, model_name_1)
+    model_name_2 = "target"
+    model_path_2 = os.path.join(models_path, model_name_1)
+
+    @staticmethod
+    def load_yaml_class(fname):
+        """Loads a yaml from the file and forms a tree item
+
+        Arguments:
+            fname {string} -- full path to the yaml file
+        """
+        _yaml = {}
+        try:
+            _size = 0
+            with open(fname, 'r') as f:
+                _yaml = yaml.load(f)
+                _size = f.tell()
+            # TODO: do smth with the data
+            if not _yaml:
+                logger_cli.warning("WARN: empty file '{}'".format(fname))
+                _yaml = {}
+            else:
+                logger.debug("...loaded YAML '{}' ({}b)".format(fname, _size))
+            return _yaml
+        except yaml.YAMLError as exc:
+            logger_cli.error(exc)
+        except IOError as e:
+            logger_cli.error(
+                "Error loading file '{}': {}".format(fname, e.message)
+            )
+            raise Exception("CRITICAL: Failed to load YAML data: {}".format(
+                e.message + e.strerror
+            ))
+
+    def load_model_tree(self, name, root_path="/srv/salt/reclass"):
+        """Walks supplied path for the YAML filed and loads the tree
+
+        Arguments:
+            root_folder_path {string} -- Path to Model's root folder. Optional
+        """
+        logger_cli.info("Loading reclass tree from '{}'".format(root_path))
+        # prepare the file tree to walk
+        raw_tree = {}
+        # Credits to Andrew Clark@MIT. Original code is here:
+        # http://code.activestate.com/recipes/577879-create-a-nested-dictionary-from-oswalk/
+        root_path = root_path.rstrip(os.sep)
+        start = root_path.rfind(os.sep) + 1
+        root_key = root_path.rsplit(os.sep, 1)[1]
+        # Look Ma! I am walking the file tree with no recursion!
+        for path, dirs, files in os.walk(root_path):
+            # if this is a hidden folder, ignore it
+            _folders_list = path[start:].split(os.sep)
+            if any(item.startswith(".") for item in _folders_list):
+                continue
+            # cut absolute part of the path and split folder names
+            folders = path[start:].split(os.sep)
+            subdir = {}
+            # create generator of files that are not hidden
+            _exts = ('.yml', '.yaml')
+            _subfiles = (_fl for _fl in files
+                         if _fl.endswith(_exts) and not _fl.startswith('.'))
+            for _file in _subfiles:
+                # cut file extension. All reclass files are '.yml'
+                _subnode = _file
+                # load all YAML class data into the tree
+                subdir[_subnode] = self.load_yaml_class(
+                    os.path.join(path, _file)
+                )
+                try:
+                    # Save original filepath, just in case
+                    subdir[_subnode]["_source"] = os.path.join(
+                        path[start:],
+                        _file
+                    )
+                except Exception:
+                    logger.warning(
+                        "Non-yaml file detected: {}".format(_file)
+                    )
+            # creating dict structure out of folder list. Pure python magic
+            parent = reduce(dict.get, folders[:-1], raw_tree)
+            parent[folders[-1]] = subdir
+        
+        self.models[name] = {}
+        # Brake in according to pathes
+        _parts = self._model_parts.keys()
+        _parts = sorted(_parts)
+        for ii in range(0, len(_parts)):
+            self.models[name][_parts[ii]] = pop_element(
+                self._model_parts[_parts[ii]],
+                raw_tree[root_key]
+            )
+        
+        # save it as a single data object
+        self.models[name]["all_diffs"] = raw_tree[root_key]
+        return True
+
+    def find_changes(self, dict1, dict2, path=""):
+        _report = {}
+        for k in dict1.keys():
+            # yamls might load values as non-str types
+            if not isinstance(k, str):
+                _new_path = path + ":" + str(k)
+            else:
+                _new_path = path + ":" + k
+            # ignore _source key
+            if k == "_source":
+                continue
+            # check if this is an env name cluster entry
+            if dict2 is not None and \
+                    k == self.model_name_1 and \
+                    self.model_name_2 in dict2.keys():
+                k1 = self.model_name_1
+                k2 = self.model_name_2
+                if type(dict1[k1]) is dict:
+                    if path == "":
+                        _new_path = k1
+                    _child_report = self.find_changes(
+                        dict1[k1],
+                        dict2[k2],
+                        _new_path
+                    )
+                    _report.update(_child_report)
+            elif dict2 is None or k not in dict2:
+                # no key in dict2
+                _report[_new_path] = {
+                    "type": "value",
+                    "raw_values": [dict1[k], "N/A"],
+                    "str_values": [
+                        "{}".format(dict1[k]),
+                        "n/a"
+                    ]
+                }
+                logger.info(
+                    "{}: {}, {}".format(_new_path, dict1[k], "N/A")
+                )
+            else:
+                if type(dict1[k]) is dict:
+                    if path == "":
+                        _new_path = k
+                    _child_report = self.find_changes(
+                        dict1[k],
+                        dict2[k],
+                        _new_path
+                    )
+                    _report.update(_child_report)
+                elif type(dict1[k]) is list and type(dict2[k]) is list:
+                    # use ifilterfalse to compare lists of dicts
+                    try:
+                        _removed = list(
+                            itertools.ifilterfalse(
+                                lambda x: x in dict2[k],
+                                dict1[k]
+                            )
+                        )
+                        _added = list(
+                            itertools.ifilterfalse(
+                                lambda x: x in dict1[k],
+                                dict2[k]
+                            )
+                        )
+                    except TypeError as e:
+                        # debug routine,
+                        # should not happen, due to list check above
+                        logger.error(
+                            "Caught lambda type mismatch: {}".format(
+                                e.message
+                            )
+                        )
+                        logger_cli.warning(
+                            "Types mismatch for correct compare: "
+                            "{}, {}".format(
+                                type(dict1[k]),
+                                type(dict2[k])
+                            )
+                        )
+                        _removed = None
+                        _added = None
+                    _original = ["= {}".format(item) for item in dict1[k]]
+                    if _removed or _added:
+                        _removed_str_lst = ["- {}".format(item)
+                                            for item in _removed]
+                        _added_str_lst = ["+ {}".format(item)
+                                            for item in _added]
+                        _report[_new_path] = {
+                            "type": "list",
+                            "raw_values": [
+                                dict1[k],
+                                _removed_str_lst + _added_str_lst
+                            ],
+                            "str_values": [
+                                "{}".format('\n'.join(_original)),
+                                "{}\n{}".format(
+                                    '\n'.join(_removed_str_lst),
+                                    '\n'.join(_added_str_lst)
+                                )
+                            ]
+                        }
+                        logger.info(
+                            "{}:\n"
+                            "{} original items total".format(
+                                _new_path,
+                                len(dict1[k])
+                            )
+                        )
+                        if _removed:
+                            logger.info(
+                                "{}".format('\n'.join(_removed_str_lst))
+                            )
+                        if _added:
+                            logger.info(
+                                "{}".format('\n'.join(_added_str_lst))
+                            )
+                else:
+                    # in case of type mismatch
+                    # considering it as not equal
+                    d1 = dict1
+                    d2 = dict2
+                    val1 = d1[k] if isinstance(d1, dict) else d1
+                    val2 = d2[k] if isinstance(d2, dict) else d2
+                    try:
+                        match = val1 == val2
+                    except TypeError as e:
+                        logger.warning(
+                            "One of the values is not a dict: "
+                            "{}, {}".format(
+                                str(dict1),
+                                str(dict2)
+                            ))
+                        match = False
+                    if not match:
+                        _report[_new_path] = {
+                            "type": "value",
+                            "raw_values": [val1, val2],
+                            "str_values": [
+                                "{}".format(val1),
+                                "{}".format(val2)
+                            ]
+                        }
+                        logger.info("{}: {}, {}".format(
+                            _new_path,
+                            val1,
+                            val2
+                        ))
+        return _report
+
+
+    def generate_model_report_tree(self):
+        """Use two loaded models to generate comparison table with
+        values are groupped by YAML files
+        """
+        # We are to cut both models into logical pieces
+        # nodes, will not be equal most of the time
+        # system, must be pretty much the same or we in trouble
+        # cluster, will be the most curious part for comparison
+        # other, all of the rest
+
+        _diff_report = {}
+        for _key in self._model_parts.keys():
+            # tmp report for keys
+            _tmp_diffs = self.find_changes(
+                self.models[self.model_name_1][_key],
+                self.models[self.model_name_2][_key]
+            )
+            # prettify the report
+            for key in _tmp_diffs.keys():
+                # break the key in two parts
+                _ext = ".yml"
+                if ".yaml" in key:
+                    _ext = ".yaml"
+                _split = key.split(_ext)
+                _file_path = _split[0]
+                _param_path = "none"
+                if len(_split) > 1:
+                    _param_path = _split[1]
+                _tmp_diffs[key].update({
+                    "class_file": _file_path + _ext,
+                    "param": _param_path,
+                })
+            _diff_report[_key[3:]] = {
+                "path": self._model_parts[_key],
+                "diffs": _tmp_diffs
+            }
+
+        _diff_report["diff_names"] = [self.model_name_1, self.model_name_2]
+        return _diff_report
+
+    def compare_models(self):
+        # Do actual compare using model names from the class
+        self.load_model_tree(
+            self.model_name_1,
+            self.model_path_1
+        )
+        self.load_model_tree(
+            self.model_name_2,
+            self.model_path_2
+        )
+        # Models should have similar structure to be compared
+        # classes/system
+        # classes/cluster
+        # nodes
+
+        diffs = self.generate_model_report_tree()
+
+        report_file = \
+            self.model_name_1 + "-vs-" + self.model_name_2 + ".html"
+        # HTML report class is post-callable
+        report = reporter.ReportToFile(
+            reporter.HTMLModelCompare(),
+            report_file
+        )
+        logger_cli.info("...generating report to {}".format(report_file))
+        # report will have tabs for each of the comparable entities in diffs
+        report({
+            "nodes": {},
+            "all_diffs": diffs,
+        })
+        # with open("./gen_tree.json", "w+") as _out:
+        #     _out.write(json.dumps(mComparer.generate_model_report_tree))
+
+        return