Add ceph methods for reweight

Adds the following methods:
- get_ceph_pg_stat
- get_ceph_health
- reweight_osd

Change-Id: I23a1563875cfa53cf4341f17ce14c5322cc955ca

ceph/__init__.py

@@ -2033,3 +2033,75 @@ def resolve_ceph_version(source):
     '''
     os_release = get_os_codename_install_source(source)
     return UCA_CODENAME_MAP.get(os_release)
+
+
+def get_ceph_pg_stat():
+    """
+    Returns the result of ceph pg stat
+    :return: dict
+    """
+    try:
+        tree = check_output(['ceph', 'pg', 'stat', '--format=json'])
+        try:
+            json_tree = json.loads(tree)
+            if not json_tree['num_pg_by_state']:
+                return None
+            return json_tree
+        except ValueError as v:
+            log("Unable to parse ceph pg stat json: {}. Error: {}".format(
+                tree, v.message))
+            raise
+    except subprocess.CalledProcessError as e:
+        log("ceph pg stat command failed with message: {}".format(
+            e.message))
+        raise
+
+
+def get_ceph_health():
+    """
+    Returns the health of the cluster from a 'ceph health'
+    :return: dict
+      Also raises CalledProcessError if our ceph command fails
+      To get the overall status, use get_ceph_health()['overall_status']
+    """
+    try:
+        tree = check_output(
+            ['ceph', 'health', '--format=json'])
+        try:
+            json_tree = json.loads(tree)
+            # Make sure children are present in the json
+            if not json_tree['overall_status']:
+                return None
+            return json_tree
+        except ValueError as v:
+            log("Unable to parse ceph tree json: {}. Error: {}".format(
+                tree, v.message))
+            raise
+    except subprocess.CalledProcessError as e:
+        log("ceph osd tree command failed with message: {}".format(
+            e.message))
+        raise
+
+
+def reweight_osd(osd_num, new_weight):
+    """
+    Changes the crush weight of an OSD to the value specified.
+    :param osd_num: the osd id which should be changed
+    :param new_weight: the new weight for the OSD
+    :returns: bool.  True if output looks right, else false.
+    :raises CalledProcessError: if an error occurs invoking the systemd cmd
+    """
+    try:
+        cmd_result = subprocess.check_output(
+            ['ceph', 'osd', 'crush', 'reweight', "osd.{}".format(osd_num),
+             new_weight], stderr=subprocess.STDOUT)
+        expected_result = "reweighted item id {ID} name \'osd.{ID}\'".format(
+                          ID=osd_num) + " to {}".format(new_weight)
+        log(cmd_result)
+        if expected_result in cmd_result:
+            return True
+        return False
+    except subprocess.CalledProcessError as e:
+        log("ceph osd tree command failed with message: {}".format(
+            e.message))
+        raise

unit_tests/test_ceph.py

@@ -16,6 +16,7 @@ import mock
 import unittest
 import ceph
 from subprocess import CalledProcessError
+import subprocess
 
 
 class TestDevice():
@@ -200,6 +201,127 @@ class CephTestCase(unittest.TestCase):
         partition_list = ceph.get_partition_list('/dev/xvdb')
         self.assertEqual(len(partition_list), 2)
 
+    @mock.patch.object(ceph, 'check_output')
+    def test_get_ceph_pg_stat(self, output):
+        """It returns the current PG stat"""
+        output.return_value = """{
+  "num_pg_by_state": [
+    {
+      "name": "active+clean",
+      "num": 320
+    }
+  ],
+  "version": 7111,
+  "num_pgs": 320,
+  "num_bytes": 118111608230,
+  "raw_bytes_used": 355042729984,
+  "raw_bytes_avail": 26627104956416,
+  "raw_bytes": 26982147686400
+}"""
+        pg_stat = ceph.get_ceph_pg_stat()
+        self.assertEqual(pg_stat['num_pgs'], 320)
+
+    @mock.patch.object(ceph, 'check_output')
+    def test_get_ceph_health(self, output):
+        """It gives the current Ceph health"""
+        output.return_value = """{
+  "health": {
+    "health_services": [
+      {
+        "mons": [
+          {
+            "name": "node1",
+            "kb_total": 2883598592,
+            "kb_used": 61728860,
+            "kb_avail": 2675368308,
+            "avail_percent": 92,
+            "last_updated": "2017-04-25 22:17:36.966046",
+            "store_stats": {
+              "bytes_total": 18612017,
+              "bytes_sst": 0,
+              "bytes_log": 2172670,
+              "bytes_misc": 16439347,
+              "last_updated": "0.000000"
+            },
+            "health": "HEALTH_OK"
+          },
+          {
+            "name": "node2",
+            "kb_total": 2883598592,
+            "kb_used": 79776472,
+            "kb_avail": 2657320696,
+            "avail_percent": 92,
+            "last_updated": "2017-04-25 22:18:27.915641",
+            "store_stats": {
+              "bytes_total": 18517923,
+              "bytes_sst": 0,
+              "bytes_log": 3340129,
+              "bytes_misc": 15177794,
+              "last_updated": "0.000000"
+            },
+            "health": "HEALTH_OK"
+          },
+          {
+            "name": "node3",
+            "kb_total": 2883598592,
+            "kb_used": 77399744,
+            "kb_avail": 2659697424,
+            "avail_percent": 92,
+            "last_updated": "2017-04-25 22:18:27.934053",
+            "store_stats": {
+              "bytes_total": 18517892,
+              "bytes_sst": 0,
+              "bytes_log": 3340129,
+              "bytes_misc": 15177763,
+              "last_updated": "0.000000"
+            },
+            "health": "HEALTH_OK"
+          }
+        ]
+      }
+    ]
+  },
+  "timechecks": {
+    "epoch": 8,
+    "round": 3022,
+    "round_status": "finished",
+    "mons": [
+      {
+        "name": "node1",
+        "skew": 0,
+        "latency": 0,
+        "health": "HEALTH_OK"
+      },
+      {
+        "name": "node2",
+        "skew": 0,
+        "latency": 0.000765,
+        "health": "HEALTH_OK"
+      },
+      {
+        "name": "node3",
+        "skew": 0,
+        "latency": 0.000765,
+        "health": "HEALTH_OK"
+      }
+    ]
+  },
+  "summary": [],
+  "overall_status": "HEALTH_OK",
+  "detail": []
+}"""
+        health = ceph.get_ceph_health()
+        self.assertEqual(health['overall_status'], "HEALTH_OK")
+
+    @mock.patch.object(subprocess, 'check_output')
+    def test_reweight_osd(self, mock_reweight):
+        """It changes the weight of an OSD"""
+        mock_reweight.return_value = "reweighted item id 0 name 'osd.0' to 1"
+        reweight_result = ceph.reweight_osd('0', '1')
+        self.assertEqual(reweight_result, True)
+        mock_reweight.assert_called_once_with(
+            ['ceph', 'osd', 'crush', 'reweight', 'osd.0', '1'], stderr=-2)
+
 
 class CephVersionTestCase(unittest.TestCase):
     @mock.patch.object(ceph, 'get_os_codename_install_source')