1# Lint as: python2, python3 2# Copyright 2014 The Chromium OS Authors. All rights reserved. 3# Use of this source code is governed by a BSD-style license that can be 4# found in the LICENSE file. 5 6"""This module provides utility functions to help managing servers in server 7database (defined in global config section AUTOTEST_SERVER_DB). 8 9After a role is added or removed from a server, certain services may need to 10be restarted. For example, scheduler needs to be restarted after a drone is 11added to a primary server. This module includes functions to check if actions 12are required to be executed and what actions to executed on which servers. 13""" 14 15from __future__ import absolute_import 16from __future__ import division 17from __future__ import print_function 18 19import subprocess 20import sys 21 22import common 23 24from autotest_lib.frontend.server import models as server_models 25from autotest_lib.site_utils import server_manager_utils 26from autotest_lib.site_utils.lib import infra 27 28 29# Actions that must be executed for server management action to be effective. 30# Each action is a tuple: 31# (the role of which the command should be executed, the command) 32RESTART_SCHEDULER = (server_models.ServerRole.ROLE.SCHEDULER, 33 'sudo service scheduler restart') 34RESTART_HOST_SCHEDULER = (server_models.ServerRole.ROLE.HOST_SCHEDULER, 35 'sudo service host-scheduler restart') 36RELOAD_APACHE = (server_models.ServerRole.ROLE.SCHEDULER, 37 'sudo service apache reload') 38 39STOP_SCHEDULER = (server_models.ServerRole.ROLE.SCHEDULER, 40 'sudo service scheduler stop') 41STOP_HOST_SCHEDULER = (server_models.ServerRole.ROLE.HOST_SCHEDULER, 42 'sudo service host-scheduler stop') 43 44# Dictionary of actions needed for a role to be enabled. Key is the role, and 45# value is a list of action. All these actions should be applied after the role 46# is added to the server, or the server's status is changed to primary. 47ACTIONS_AFTER_ROLE_APPLIED = { 48 server_models.ServerRole.ROLE.SCHEDULER: [RESTART_SCHEDULER], 49 server_models.ServerRole.ROLE.HOST_SCHEDULER: [RESTART_HOST_SCHEDULER], 50 server_models.ServerRole.ROLE.DRONE: [RESTART_SCHEDULER], 51 server_models.ServerRole.ROLE.DATABASE: 52 [RESTART_SCHEDULER, RESTART_HOST_SCHEDULER, RELOAD_APACHE], 53 server_models.ServerRole.ROLE.DEVSERVER: [RESTART_SCHEDULER], 54 } 55 56# Dictionary of actions needed for a role to be disabled. Key is the role, and 57# value is a list of action. 58# Action should be taken before role is deleted from a server, or the server's 59# status is changed to primary. 60ACTIONS_BEFORE_ROLE_REMOVED = { 61 server_models.ServerRole.ROLE.SCHEDULER: [STOP_SCHEDULER], 62 server_models.ServerRole.ROLE.HOST_SCHEDULER: [STOP_HOST_SCHEDULER], 63 server_models.ServerRole.ROLE.DATABASE: 64 [STOP_SCHEDULER, STOP_HOST_SCHEDULER], 65 } 66# Action should be taken after role is deleted from a server, or the server's 67# status is changed to primary. 68ACTIONS_AFTER_ROLE_REMOVED = { 69 server_models.ServerRole.ROLE.DRONE: [RESTART_SCHEDULER], 70 server_models.ServerRole.ROLE.DEVSERVER: [RESTART_SCHEDULER], 71 } 72 73 74def apply(action): 75 """Apply an given action. 76 77 It usually involves ssh to the server with specific role and run the 78 command, e.g., ssh to scheduler server and restart scheduler. 79 80 @param action: A tuple of (the role of which the command should be executed, 81 the command) 82 @raise ServerActionError: If the action can't be applied due to database 83 issue. 84 @param subprocess.CalledProcessError: If command is failed to be 85 executed. 86 """ 87 role = action[0] 88 command = action[1] 89 # Find the servers with role 90 servers = server_manager_utils.get_servers( 91 role=role, status=server_models.Server.STATUS.PRIMARY) 92 if not servers: 93 print('WARNING! Action %s failed to be applied. No ' 94 'server with given role %s was found.' % (action, role), 95 file=sys.stderr) 96 return 97 98 for server in servers: 99 print('Run command `%s` on server %s' % (command, server.hostname)) 100 try: 101 infra.execute_command(server.hostname, command) 102 except subprocess.CalledProcessError as e: 103 print('Failed to check server %s, error: %s' % 104 (server.hostname, e), file=sys.stderr) 105 106 107def try_execute(server, roles, enable, post_change, 108 prev_status=server_models.Server.STATUS.REPAIR_REQUIRED, 109 do_action=False): 110 """Try to execute actions for given role changes of the server. 111 112 @param server: Server that has the role changes. 113 @param roles: A list of roles changed. 114 @param enable: Set to True if the roles are enabled, i.e., added to server. 115 If it's False, the roles are removed from the server. 116 @param post_change: Set to True if to apply actions should be applied after 117 the role changes, otherwise, set to False. 118 @param prev_status: The previous status after the status change if any. This 119 is to help to decide if actions should be executed, 120 since actions should be applied if the server's status 121 is changed from primary to other status. Default to 122 repair_required. 123 @param do_action: Set to True to execute actions, otherwise, post a warning. 124 """ 125 if not server_manager_utils.use_server_db(): 126 return 127 # This check is to prevent actions to be applied to server not in primary 128 # role or server database is not enabled. Note that no action is needed 129 # before a server is changed to primary status. If that assumption is 130 # no longer valid, this method needs to be updated accordingly. 131 if (server.status != server_models.Server.STATUS.PRIMARY and 132 prev_status != server_models.Server.STATUS.PRIMARY): 133 return 134 135 possible_actions = {} 136 if enable: 137 if post_change: 138 possible_actions = ACTIONS_AFTER_ROLE_APPLIED 139 else: 140 if post_change: 141 possible_actions = ACTIONS_AFTER_ROLE_REMOVED 142 else: 143 possible_actions = ACTIONS_BEFORE_ROLE_REMOVED 144 145 all_actions = [] 146 for role in roles: 147 all_actions.extend(possible_actions.get(role, [])) 148 for action in set(all_actions): 149 if do_action: 150 apply(action) 151 else: 152 message = ('WARNING! Action %s is skipped. Please manually ' 153 'execute the action to make your change effective.' % 154 str(action)) 155 print(message, file=sys.stderr) 156