1 # Copyright 2014 The Chromium OS Authors. All rights reserved. 2 # Use of this source code is governed by a BSD-style license that can be 3 # found in the LICENSE file. 4 5 """This module provides utility functions to help managing servers in server 6 database (defined in global config section AUTOTEST_SERVER_DB). 7 8 After a role is added or removed from a server, certain services may need to 9 be restarted. For example, scheduler needs to be restarted after a drone is 10 added to a primary server. This module includes functions to check if actions 11 are required to be executed and what actions to executed on which servers. 12 """ 13 14 import subprocess 15 import sys 16 17 import common 18 19 from autotest_lib.frontend.server import models as server_models 20 from autotest_lib.site_utils import server_manager_utils 21 from autotest_lib.site_utils.lib import infra 22 23 24 # Actions that must be executed for server management action to be effective. 25 # Each action is a tuple: 26 # (the role of which the command should be executed, the command) 27 RESTART_SCHEDULER = (server_models.ServerRole.ROLE.SCHEDULER, 28 'sudo service scheduler restart') 29 RESTART_HOST_SCHEDULER = (server_models.ServerRole.ROLE.HOST_SCHEDULER, 30 'sudo service host-scheduler restart') 31 RESTART_SUITE_SCHEDULER = (server_models.ServerRole.ROLE.SUITE_SCHEDULER, 32 'sudo service suite_scheduler restart') 33 RELOAD_APACHE = (server_models.ServerRole.ROLE.SCHEDULER, 34 'sudo service apache reload') 35 36 STOP_SCHEDULER = (server_models.ServerRole.ROLE.SCHEDULER, 37 'sudo service scheduler stop') 38 STOP_HOST_SCHEDULER = (server_models.ServerRole.ROLE.HOST_SCHEDULER, 39 'sudo service host-scheduler stop') 40 STOP_SUITE_SCHEDULER = (server_models.ServerRole.ROLE.SUITE_SCHEDULER, 41 'sudo service suite_scheduler stop') 42 43 # Dictionary of actions needed for a role to be enabled. Key is the role, and 44 # value is a list of action. All these actions should be applied after the role 45 # is added to the server, or the server's status is changed to primary. 46 ACTIONS_AFTER_ROLE_APPLIED = { 47 server_models.ServerRole.ROLE.SCHEDULER: [RESTART_SCHEDULER], 48 server_models.ServerRole.ROLE.HOST_SCHEDULER: [RESTART_HOST_SCHEDULER], 49 server_models.ServerRole.ROLE.SUITE_SCHEDULER: 50 [RESTART_SUITE_SCHEDULER], 51 server_models.ServerRole.ROLE.DRONE: [RESTART_SCHEDULER], 52 server_models.ServerRole.ROLE.DATABASE: 53 [RESTART_SCHEDULER, RESTART_HOST_SCHEDULER, RELOAD_APACHE], 54 server_models.ServerRole.ROLE.DEVSERVER: [RESTART_SCHEDULER], 55 } 56 57 # Dictionary of actions needed for a role to be disabled. Key is the role, and 58 # value is a list of action. 59 # Action should be taken before role is deleted from a server, or the server's 60 # status is changed to primary. 61 ACTIONS_BEFORE_ROLE_REMOVED = { 62 server_models.ServerRole.ROLE.SCHEDULER: [STOP_SCHEDULER], 63 server_models.ServerRole.ROLE.HOST_SCHEDULER: [STOP_HOST_SCHEDULER], 64 server_models.ServerRole.ROLE.SUITE_SCHEDULER: [STOP_SUITE_SCHEDULER], 65 server_models.ServerRole.ROLE.DATABASE: 66 [STOP_SCHEDULER, STOP_HOST_SCHEDULER], 67 } 68 # Action should be taken after role is deleted from a server, or the server's 69 # status is changed to primary. 70 ACTIONS_AFTER_ROLE_REMOVED = { 71 server_models.ServerRole.ROLE.DRONE: [RESTART_SCHEDULER], 72 server_models.ServerRole.ROLE.DEVSERVER: [RESTART_SCHEDULER], 73 } 74 75 76 def apply(action): 77 """Apply an given action. 78 79 It usually involves ssh to the server with specific role and run the 80 command, e.g., ssh to scheduler server and restart scheduler. 81 82 @param action: A tuple of (the role of which the command should be executed, 83 the command) 84 @raise ServerActionError: If the action can't be applied due to database 85 issue. 86 @param subprocess.CalledProcessError: If command is failed to be 87 executed. 88 """ 89 role = action[0] 90 command = action[1] 91 # Find the servers with role 92 servers = server_manager_utils.get_servers( 93 role=role, status=server_models.Server.STATUS.PRIMARY) 94 if not servers: 95 print >> sys.stderr, ('WARNING! Action %s failed to be applied. No ' 96 'server with given role %s was found.' % 97 (action, role)) 98 return 99 100 for server in servers: 101 print 'Run command `%s` on server %s' % (command, server.hostname) 102 try: 103 infra.execute_command(server.hostname, command) 104 except subprocess.CalledProcessError as e: 105 print >> sys.stderr, ('Failed to check server %s, error: %s' % 106 (server.hostname, e)) 107 108 109 def try_execute(server, roles, enable, post_change, 110 prev_status=server_models.Server.STATUS.BACKUP, 111 do_action=False): 112 """Try to execute actions for given role changes of the server. 113 114 @param server: Server that has the role changes. 115 @param roles: A list of roles changed. 116 @param enable: Set to True if the roles are enabled, i.e., added to server. 117 If it's False, the roles are removed from the server. 118 @param post_change: Set to True if to apply actions should be applied after 119 the role changes, otherwise, set to False. 120 @param prev_status: The previous status after the status change if any. This 121 is to help to decide if actions should be executed, 122 since actions should be applied if the server's status 123 is changed from primary to other status. Default to 124 backup. 125 @param do_action: Set to True to execute actions, otherwise, post a warning. 126 """ 127 if not server_manager_utils.use_server_db(): 128 return 129 # This check is to prevent actions to be applied to server not in primary 130 # role or server database is not enabled. Note that no action is needed 131 # before a server is changed to primary status. If that assumption is 132 # no longer valid, this method needs to be updated accordingly. 133 if (server.status != server_models.Server.STATUS.PRIMARY and 134 prev_status != server_models.Server.STATUS.PRIMARY): 135 return 136 137 if enable: 138 if post_change: 139 possible_actions = ACTIONS_AFTER_ROLE_APPLIED 140 else: 141 if post_change: 142 possible_actions = ACTIONS_AFTER_ROLE_REMOVED 143 else: 144 possible_actions = ACTIONS_BEFORE_ROLE_REMOVED 145 146 all_actions = [] 147 for role in roles: 148 all_actions.extend(possible_actions.get(role, [])) 149 for action in set(all_actions): 150 if do_action: 151 apply(action) 152 else: 153 message = ('WARNING! Action %s is skipped. Please manually ' 154 'execute the action to make your change effective.' % 155 str(action)) 156 print >> sys.stderr, message 157
