Check for IP addresses assigned to multiple hosts

added a check in dynamic_inventory to discover
ip addresses assigned to more than one host in
openstack_user_config and warn users in case of any.

Change-Id: I5fc9c6441e82ccd37ab23ba2e194e30ae7918f00

playbooks/inventory/dynamic_inventory.py

@@ -49,6 +49,22 @@ REQUIRED_HOSTVARS = [
 ]
 
 
+class MultipleHostsWithOneIPError(Exception):
+    def __init__(self, ip, assigned_host, new_host):
+        self.ip = ip
+        self.assigned_host = assigned_host
+        self.new_host = new_host
+
+        error_msg = ("ip address:{} has already been "
+                     "assigned to host:{}, cannot "
+                     "assign same ip to host:{}")
+
+        self.message = error_msg.format(ip, assigned_host, new_host)
+
+    def __str__(self):
+        return self.message
+
+
 def args():
     """Setup argument Parsing."""
     parser = argparse.ArgumentParser(
@@ -855,6 +871,26 @@ def _extra_config(user_defined_config, base_dir):
                     )
 
 
+def _check_same_ip_to_multiple_host(config):
+    """Check for IPs assigned to multiple hosts
+
+    : param: config:  ``dict`` User provided configuration
+    """
+
+    ips_to_hostnames_mapping = dict()
+    for key, value in config.iteritems():
+        if key.endswith('hosts'):
+            for _key, _value in value.iteritems():
+                hostname = _key
+                ip = _value['ip']
+                if not (ip in ips_to_hostnames_mapping):
+                    ips_to_hostnames_mapping[ip] = hostname
+                else:
+                    if ips_to_hostnames_mapping[ip] != hostname:
+                        info = (ip, ips_to_hostnames_mapping[ip], hostname)
+                        raise MultipleHostsWithOneIPError(*info)
+
+
 def _check_config_settings(cidr_networks, config, container_skel):
     """check preciseness of config settings
 
@@ -896,6 +932,8 @@ def _check_config_settings(cidr_networks, config, container_skel):
                     raise SystemExit(
                         "can't find " + q_name + " in cidr_networks"
                     )
+    # look for same ip address assigned to different hosts
+    _check_same_ip_to_multiple_host(config)
 
 
 def load_environment(config_path):

tests/test_inventory.py

@@ -329,8 +329,8 @@ class TestIps(unittest.TestCase):
 
 
 class TestConfigChecks(unittest.TestCase):
-
     def setUp(self):
+        self.config_changed = False
         self.user_defined_config = dict()
         with open(USER_CONFIG_FILE, 'rb') as f:
             self.user_defined_config.update(yaml.safe_load(f.read()) or {})
@@ -351,6 +351,7 @@ class TestConfigChecks(unittest.TestCase):
         self.write_config()
 
     def write_config(self):
+        self.config_changed = True
         # rename temporarily our user_config_file so we can use the new one
         os.rename(USER_CONFIG_FILE, USER_CONFIG_FILE + ".tmp")
         # Save new user_config_file
@@ -380,6 +381,14 @@ class TestConfigChecks(unittest.TestCase):
         expectedLog = "No container CIDR specified in user config"
         self.assertEqual(context.exception.message, expectedLog)
 
+    def set_new_hostname(self, user_defined_config, group,
+                         old_hostname, new_hostname):
+        self.config_changed = True
+        # set a new name for the specified hostname
+        old_hostname_settings = user_defined_config[group].pop(old_hostname)
+        user_defined_config[group][new_hostname] = old_hostname_settings
+        self.write_config()
+
     def test_provider_networks_check(self):
         # create config file without provider networks
         self.delete_config_key(self.user_defined_config, 'provider_networks')
@@ -398,10 +407,42 @@ class TestConfigChecks(unittest.TestCase):
         expectedLog = "global_overrides can't be found in user config"
         self.assertEqual(context.exception.message, expectedLog)
 
+    def test_two_hosts_same_ip(self):
+        # Use an OrderedDict to be certain our testing order is preserved
+        # Even with the same hash seed, different OSes get different results,
+        # eg. local OS X vs gate's Linux
+        config = collections.OrderedDict()
+        config['infra_hosts'] = {
+            'host1': {
+                'ip': '192.168.1.1'
+            }
+        }
+        config['compute_hosts'] = {
+            'host2': {
+                'ip': '192.168.1.1'
+            }
+        }
+
+        with self.assertRaises(di.MultipleHostsWithOneIPError) as context:
+            di._check_same_ip_to_multiple_host(config)
+        self.assertEqual(context.exception.ip, '192.168.1.1')
+        self.assertEqual(context.exception.assigned_host, 'host1')
+        self.assertEqual(context.exception.new_host, 'host2')
+
+    def test_two_hosts_same_ip_externally(self):
+        self.set_new_hostname(self.user_defined_config, "haproxy_hosts",
+                              "aio1", "hap")
+        with self.assertRaises(di.MultipleHostsWithOneIPError) as context:
+            get_inventory()
+        expectedLog = ("ip address:172.29.236.100 has already been assigned"
+                       " to host:aio1, cannot assign same ip to host:hap")
+        self.assertEqual(context.exception.message, expectedLog)
+
     def tearDown(self):
-        # get back our initial user config file
-        os.remove(USER_CONFIG_FILE)
-        os.rename(USER_CONFIG_FILE + ".tmp", USER_CONFIG_FILE)
+        if self.config_changed:
+            # get back our initial user config file
+            os.remove(USER_CONFIG_FILE)
+            os.rename(USER_CONFIG_FILE + ".tmp", USER_CONFIG_FILE)
 
 
 if __name__ == '__main__':