Skeleton and sensors works
diff --git a/wally/ceph.py b/wally/ceph.py
index 1e79126..cbb4740 100644
--- a/wally/ceph.py
+++ b/wally/ceph.py
@@ -1,7 +1,7 @@
 """ Collect data about ceph nodes"""
 import json
 import logging
-from typing import Set, Dict, cast
+from typing import Dict, cast, List, Set, Optional
 
 
 from .node_interfaces import NodeInfo, IRPCNode
@@ -11,22 +11,30 @@
 from .test_run_class import TestRun
 from .ssh_utils import parse_ssh_uri
 from .node import connect, setup_rpc
+from .utils import StopTestError
 
 
-logger = logging.getLogger("wally.discover")
+logger = logging.getLogger("wally")
 
 
-def get_osds_ips(node: IRPCNode, conf: str, key: str) -> Set[IP]:
+class OSDInfo:
+    def __init__(self, id: int, journal: str = None, storage: str = None) -> None:
+        self.id = id
+        self.journal = journal
+        self.storage = storage
+
+
+def get_osds_info(node: IRPCNode, conf: str, key: str) -> Dict[IP, List[OSDInfo]]:
     """Get set of osd's ip"""
 
     data = node.run("ceph -c {} -k {} --format json osd dump".format(conf, key))
     jdata = json.loads(data)
-    ips = set()  # type: Set[IP]
+    ips = {}  # type: Dict[IP, List[OSDInfo]]
     first_error = True
     for osd_data in jdata["osds"]:
+        osd_id = int(osd_data["osd"])
         if "public_addr" not in osd_data:
             if first_error:
-                osd_id = osd_data.get("osd", "<OSD_ID_MISSED>")
                 logger.warning("No 'public_addr' field in 'ceph osd dump' output for osd %s" +
                                "(all subsequent errors omitted)", osd_id)
                 first_error = False
@@ -34,7 +42,26 @@
             ip_port = osd_data["public_addr"]
             if '/' in ip_port:
                 ip_port = ip_port.split("/", 1)[0]
-            ips.add(IP(ip_port.split(":")[0]))
+            ip = IP(ip_port.split(":")[0])
+
+            osd_journal_path = None  # type: Optional[str]
+            osd_data_path = None  # type: Optional[str]
+
+            # TODO: parallelize this!
+            osd_cfg = node.run("ceph -n osd.{} --show-config".format(osd_id))
+            for line in osd_cfg.split("\n"):
+                if line.startswith("osd_journal ="):
+                    osd_journal_path = line.split("=")[1].strip()
+                elif line.startswith("osd_data ="):
+                    osd_data_path = line.split("=")[1].strip()
+
+            if osd_data_path is None or osd_journal_path is None:
+                logger.error("Can't detect osd %s journal or storage path", osd_id)
+                raise StopTestError()
+
+            ips.setdefault(ip, []).append(OSDInfo(osd_id,
+                                                  journal=osd_journal_path,
+                                                  storage=osd_data_path))
     return ips
 
 
@@ -68,45 +95,71 @@
     def run(self, ctx: TestRun) -> None:
         """Return list of ceph's nodes NodeInfo"""
 
-        if 'ceph_nodes' in ctx.storage:
-            ctx.nodes_info.extend(ctx.storage.load_list(NodeInfo, 'ceph_nodes'))
-        else:
-            ceph = ctx.config.ceph
-            root_node_uri = cast(str, ceph.root_node)
-            cluster = ceph.get("cluster", "ceph")
-            conf = ceph.get("conf")
-            key = ceph.get("key")
-            info = NodeInfo(parse_ssh_uri(root_node_uri), set())
-            ceph_nodes = {}  # type: Dict[IP, NodeInfo]
+        discovery = ctx.config.get("discovery")
+        if discovery == 'disable' or discovery == 'metadata':
+            logger.info("Skip ceph discovery due to config setting")
+            return
 
-            if conf is None:
-                conf = "/etc/ceph/{}.conf".format(cluster)
+        if 'all_nodes' in ctx.storage:
+            logger.debug("Skip ceph discovery, use previously discovered nodes")
+            return
 
-            if key is None:
-                key = "/etc/ceph/{}.client.admin.keyring".format(cluster)
+        ceph = ctx.config.ceph
+        root_node_uri = cast(str, ceph.root_node)
+        cluster = ceph.get("cluster", "ceph")
+        conf = ceph.get("conf")
+        key = ceph.get("key")
 
-            with setup_rpc(connect(info), ctx.rpc_code, ctx.default_rpc_plugins) as node:
+        logger.debug("Start discovering ceph nodes from root %s", root_node_uri)
+        logger.debug("cluster=%s key=%s conf=%s", cluster, conf, key)
 
-                # new_nodes.extend(ceph.discover_ceph_nodes(ceph_root_conn, cluster=cluster, conf=conf, key=key))
-                ssh_key = node.get_file_content("~/.ssh/id_rsa")
+        info = NodeInfo(parse_ssh_uri(root_node_uri), set())
 
-                try:
-                    for ip in get_osds_ips(node, conf, key):
-                        if ip in ceph_nodes:
-                            ceph_nodes[ip].roles.add("ceph-osd")
-                        else:
-                            ceph_nodes[ip] = NodeInfo(ConnCreds(cast(str, ip), user="root", key=ssh_key), {"ceph-osd"})
-                except Exception as exc:
-                    logger.error("OSD discovery failed: %s", exc)
+        if conf is None:
+            conf = "/etc/ceph/{}.conf".format(cluster)
 
-                try:
-                    for ip in get_mons_ips(node, conf, key):
-                        if ip in ceph_nodes:
-                            ceph_nodes[ip].roles.add("ceph-mon")
-                        else:
-                            ceph_nodes[ip] = NodeInfo(ConnCreds(cast(str, ip), user="root", key=ssh_key), {"ceph-mon"})
-                except Exception as exc:
-                    logger.error("MON discovery failed: %s", exc)
+        if key is None:
+            key = "/etc/ceph/{}.client.admin.keyring".format(cluster)
 
-            ctx.nodes_info.extend(ceph_nodes.values())
-            ctx.storage['ceph-nodes'] = list(ceph_nodes.values())
+        ceph_params = {"cluster": cluster, "conf": conf, "key": key}
+
+        with setup_rpc(connect(info),
+                       ctx.rpc_code,
+                       ctx.default_rpc_plugins,
+                       log_level=ctx.config.rpc_log_level) as node:
+
+            ssh_key = node.get_file_content("~/.ssh/id_rsa")
+
+
+            try:
+                ips = set()
+                for ip, osds_info in get_osds_info(node, conf, key).items():
+                    ips.add(ip)
+                    creds = ConnCreds(cast(str, ip), user="root", key=ssh_key)
+                    info = ctx.merge_node(creds, {'ceph-osd'})
+                    info.params.setdefault('ceph-osds', []).extend(osds_info)
+                    assert 'ceph' not in info.params or info.params['ceph'] == ceph_params
+                    info.params['ceph'] = ceph_params
+
+                logger.debug("Found %s nodes with ceph-osd role", len(ips))
+            except Exception as exc:
+                if discovery != 'ignore_errors':
+                    logger.exception("OSD discovery failed")
+                    raise StopTestError()
+                else:
+                    logger.warning("OSD discovery failed %s", exc)
+
+            try:
+                counter = 0
+                for counter, ip in enumerate(get_mons_ips(node, conf, key)):
+                    creds = ConnCreds(cast(str, ip), user="root", key=ssh_key)
+                    info = ctx.merge_node(creds, {'ceph-mon'})
+                    assert 'ceph' not in info.params or info.params['ceph'] == ceph_params
+                    info.params['ceph'] = ceph_params
+                logger.debug("Found %s nodes with ceph-mon role", counter + 1)
+            except Exception as exc:
+                if discovery != 'ignore_errors':
+                    logger.exception("MON discovery failed")
+                    raise StopTestError()
+                else:
+                    logger.warning("MON discovery failed %s", exc)