Coverage for manila/scheduler/filters/share_replication.py: 100%

1# Copyright (c) 2016 Goutham Pacha Ravi 

2# All Rights Reserved. 

3# 

4# Licensed under the Apache License, Version 2.0 (the "License"); you may 

5# not use this file except in compliance with the License. You may obtain 

6# a copy of the License at 

7# 

8# http://www.apache.org/licenses/LICENSE-2.0 

9# 

10# Unless required by applicable law or agreed to in writing, software 

11# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 

12# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 

13# License for the specific language governing permissions and limitations 

14# under the License. 

15 

16from oslo_log import log 

17 

18from manila.scheduler.filters import base_host 

19 

20LOG = log.getLogger(__name__) 

21 

22 

23class ShareReplicationFilter(base_host.BaseHostFilter): 

24 """ShareReplicationFilter filters hosts based on replication support.""" 

25 

26 def host_passes(self, host_state, filter_properties): 

27 """Return True if 'active' replica's host can replicate with host. 

28 

29 Design of this filter: 

30 

31 - Share replication is symmetric. All backends that can 

32 replicate between each other must share the same 

33 'replication_domain'. 

34 - For scheduling a share that can be replicated in the future, 

35 this filter checks for 'replication_domain' capability. 

36 - For scheduling a replica, it checks for the 

37 'replication_domain' compatibility. 

38 

39 """ 

40 active_replica_host = filter_properties.get('request_spec', {}).get( 

41 'active_replica_host') 

42 existing_replica_hosts = filter_properties.get('request_spec', {}).get( 

43 'all_replica_hosts', '').split(',') 

44 replication_type = filter_properties.get('resource_type', {}).get( 

45 'extra_specs', {}).get('replication_type') 

46 active_replica_replication_domain = filter_properties.get( 

47 'replication_domain') 

48 host_replication_domain = host_state.replication_domain 

49 

50 if replication_type is None: 

51 # NOTE(gouthamr): You're probably not creating a replicated 

52 # share or a replica, then this host obviously passes. 

53 return True 

54 elif host_replication_domain is None: 

55 msg = "Replication is not enabled on host %s." 

56 LOG.debug(msg, host_state.host) 

57 return False 

58 elif active_replica_host is None: 

59 # 'replication_type' filtering will be handled by the 

60 # capabilities filter, since it is a share-type extra-spec. 

61 return True 

62 

63 # Scheduler filtering by replication_domain for a replica 

64 if active_replica_replication_domain != host_replication_domain: 

65 msg = ("The replication domain of Host %(host)s is " 

66 "'%(host_domain)s' and it does not match the replication " 

67 "domain of the 'active' replica's host: " 

68 "%(active_replica_host)s, which is '%(arh_domain)s'. ") 

69 kwargs = { 

70 "host": host_state.host, 

71 "host_domain": host_replication_domain, 

72 "active_replica_host": active_replica_host, 

73 "arh_domain": active_replica_replication_domain, 

74 } 

75 LOG.debug(msg, kwargs) 

76 return False 

77 

78 # Check host string for already created replicas 

79 if host_state.host in existing_replica_hosts: 

80 msg = ("Skipping host %s since it already hosts a replica for " 

81 "this share.") 

82 LOG.debug(msg, host_state.host) 

83 return False 

84 

85 return True