blob: c9ca4edd7e186205292e9e61112dd17e350eae33 [file] [log] [blame]
#!/usr/bin/env python
# Copyright 2015 The Chromium OS Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""Adjust pool balances to cover DUT shortfalls.
This command takes all broken DUTs in a specific pool for specific
boards and swaps them with working DUTs taken from a selected pool
of spares. The command is meant primarily for replacing broken DUTs
in critical pools like BVT or CQ, but it can also be used to adjust
pool sizes, or to create or remove pools.
usage: [ options ] POOL BOARD [ BOARD ... ]
positional arguments:
POOL Name of the pool to balance
BOARD Names of boards to balance
optional arguments:
-h, --help show this help message and exit
-t COUNT, --total COUNT
Set the number of DUTs in the pool to the specified
count for every BOARD
-a COUNT, --grow COUNT
Add the specified number of DUTs to the pool for every
-d COUNT, --shrink COUNT
Remove the specified number of DUTs from the pool for
every BOARD
-s POOL, --spare POOL
Pool from which to draw replacement spares (default:
-n, --dry-run Report actions to take in the form of shell commands
The command attempts to remove all broken DUTs from the target POOL
for every BOARD, and replace them with enough working DUTs taken
from the spare pool to bring the strength of POOL to the requested
total COUNT.
If no COUNT options are supplied (i.e. there are no --total, --grow,
or --shrink options), the command will maintain the current totals of
DUTs for every BOARD in the target POOL.
If not enough working spares are available, broken DUTs may be left
in the pool to keep the pool at the target COUNT.
When reducing pool size, working DUTs will be returned after broken
DUTs, if it's necessary to achieve the target COUNT.
import argparse
import sys
import time
import common
from autotest_lib.server import frontend
from autotest_lib.server.lib import status_history
from autotest_lib.site_utils import lab_inventory
from autotest_lib.site_utils.suite_scheduler import constants
from chromite.lib import parallel
_POOL_PREFIX = constants.Labels.POOL_PREFIX
# This is the ratio of all boards we should calculate the default max number of
# broken boards against. It seemed like the best choice that was neither too
# strict nor lax.
_ALL_CRITICAL_POOLS = 'all_critical_pools'
def _log_message(message, *args):
"""Log a message with optional format arguments to stdout.
This function logs a single line to stdout, with formatting
if necessary, and without adornments.
If `*args` are supplied, the message will be formatted using
the arguments.
@param message Message to be logged, possibly after formatting.
@param args Format arguments. If empty, the message is logged
without formatting.
if args:
message = message % args
sys.stdout.write('%s\n' % message)
def _log_info(dry_run, message, *args):
"""Log information in a dry-run dependent fashion.
This function logs a single line to stdout, with formatting
if necessary. When logging for a dry run, the message is
printed as a shell comment, rather than as unadorned text.
If `*args` are supplied, the message will be formatted using
the arguments.
@param message Message to be logged, possibly after formatting.
@param args Format arguments. If empty, the message is logged
without formatting.
if dry_run:
message = '# ' + message
_log_message(message, *args)
def _log_error(message, *args):
"""Log an error to stderr, with optional format arguments.
This function logs a single line to stderr, prefixed to indicate
that it is an error message.
If `*args` are supplied, the message will be formatted using
the arguments.
@param message Message to be logged, possibly after formatting.
@param args Format arguments. If empty, the message is logged
without formatting.
if args:
message = message % args
sys.stderr.write('ERROR: %s\n' % message)
class _DUTPool(object):
"""Information about a pool of DUTs for a given board.
This class collects information about all DUTs for a given
board and pool pair, and divides them into three categories:
+ Working - the DUT is working for testing, and not locked.
+ Broken - the DUT is unable to run tests, or it is locked.
+ Ineligible - the DUT is not available to be removed from
this pool. The DUT may be either working or broken.
DUTs with more than one pool: label are ineligible for exchange
during balancing. This is done for the sake of chameleon hosts,
which must always be assigned to pool:suites. These DUTs are
always marked with pool:chameleon to prevent their reassignment.
TODO(jrbarnette): The use of `pool:chamelon` (instead of just
the `chameleon` label is a hack that should be eliminated.
_DUTPool instances are used to track both main pools that need
to be resupplied with working DUTs and spare pools that supply
those DUTs.
@property board Name of the board associated with
this pool of DUTs.
@property pool Name of the pool associated with
this pool of DUTs.
@property working_hosts The list of this pool's working
@property broken_hosts The list of this pool's broken
@property ineligible_hosts The list of this pool's ineligible DUTs.
@property labels A list of labels that identify a DUT
as part of this pool.
@property total_hosts The total number of hosts in pool.
def __init__(self, afe, board, pool, start_time, end_time):
self.board = board
self.pool = pool
self.working_hosts = []
self.broken_hosts = []
self.ineligible_hosts = []
self.total_hosts = self._get_hosts(afe, start_time, end_time)
self._labels = [_POOL_PREFIX + self.pool]
def _get_hosts(self, afe, start_time, end_time):
all_histories = (
afe, start_time, end_time,
board=self.board, pool=self.pool))
for h in all_histories:
host =
host_pools = [l for l in host.labels
if l.startswith(_POOL_PREFIX)]
if len(host_pools) != 1:
diag = h.last_diagnosis()[0]
if (diag == status_history.WORKING and
not host.locked):
return len(all_histories)
def pool_labels(self):
"""Return the AFE labels that identify this pool.
The returned labels are the labels that must be removed
to remove a DUT from the pool, or added to add a DUT.
@return A list of AFE labels suitable for AFE.add_labels()
or AFE.remove_labels().
return self._labels
def calculate_spares_needed(self, target_total):
"""Calculate and log the spares needed to achieve a target.
Return how many working spares are needed to achieve the
given `target_total` with all DUTs working.
The spares count may be positive or negative. Positive
values indicate spares are needed to replace broken DUTs in
order to reach the target; negative numbers indicate that
no spares are needed, and that a corresponding number of
working devices can be returned.
If the new target total would require returning ineligible
DUTs, an error is logged, and the target total is adjusted
so that those DUTs are not exchanged.
@param target_total The new target pool size.
@return The number of spares needed.
num_ineligible = len(self.ineligible_hosts)
if target_total < num_ineligible:
_log_error('%s %s pool: Target of %d is below '
'minimum of %d DUTs.',
self.board, self.pool,
target_total, num_ineligible)
_log_error('Adjusting target to %d DUTs.', num_ineligible)
target_total = num_ineligible
adjustment = target_total - self.total_hosts
return len(self.broken_hosts) + adjustment
def allocate_surplus(self, num_broken):
"""Allocate a list DUTs that can returned as surplus.
Return a list of devices that can be returned in order to
reduce this pool's supply. Broken DUTs will be preferred
over working ones.
The `num_broken` parameter indicates the number of broken
DUTs to be left in the pool. If this number exceeds the
number of broken DUTs actually in the pool, the returned
list will be empty. If this number is negative, it
indicates a number of working DUTs to be returned in
addition to all broken ones.
@param num_broken Total number of broken DUTs to be left in
this pool.
@return A list of DUTs to be returned as surplus.
if num_broken >= 0:
surplus = self.broken_hosts[num_broken:]
return surplus
return (self.broken_hosts +
def _exchange_labels(dry_run, hosts, target_pool, spare_pool):
"""Reassign a list of DUTs from one pool to another.
For all the given hosts, remove all labels associated with
`spare_pool`, and add the labels for `target_pool`.
If `dry_run` is true, perform no changes, but log the `atest`
commands needed to accomplish the necessary label changes.
@param dry_run Whether the logging is for a dry run or
for actual execution.
@param hosts List of DUTs (AFE hosts) to be reassigned.
@param target_pool The `_DUTPool` object from which the hosts
are drawn.
@param spare_pool The `_DUTPool` object to which the hosts
will be added.
if not hosts:
_log_info(dry_run, 'Transferring %d DUTs from %s to %s.',
len(hosts), spare_pool.pool, target_pool.pool)
additions = target_pool.pool_labels
removals = spare_pool.pool_labels
for host in hosts:
if not dry_run:
_log_message('Updating host: %s.', host.hostname)
_log_message('atest label remove -m %s %s',
host.hostname, ' '.join(removals))
_log_message('atest label add -m %s %s',
host.hostname, ' '.join(additions))
def _balance_board(arguments, afe, board, pool, start_time, end_time):
"""Balance one board as requested by command line arguments.
@param arguments Parsed command line arguments.
@param dry_run Whether the logging is for a dry run or
for actual execution.
@param afe AFE object to be used for the changes.
@param board Board to be balanced.
@param pool Pool of the board to be balanced.
@param start_time Start time for HostJobHistory objects in
the DUT pools.
@param end_time End time for HostJobHistory objects in the
DUT pools.
spare_pool = _DUTPool(afe, board, arguments.spare,
start_time, end_time)
main_pool = _DUTPool(afe, board, pool,
start_time, end_time)
target_total = main_pool.total_hosts
if is not None:
target_total =
elif arguments.grow:
target_total += arguments.grow
elif arguments.shrink:
target_total -= arguments.shrink
spares_needed = main_pool.calculate_spares_needed(target_total)
if spares_needed > 0:
spare_duts = spare_pool.working_hosts[:spares_needed]
shortfall = spares_needed - len(spare_duts)
spare_duts = []
shortfall = spares_needed
surplus_duts = main_pool.allocate_surplus(shortfall)
if spares_needed or surplus_duts or arguments.verbose:
dry_run = arguments.dry_run
_log_info(dry_run, 'Balancing %s %s pool:', board, main_pool.pool)
'Total %d DUTs, %d working, %d broken, %d reserved.',
main_pool.total_hosts, len(main_pool.working_hosts),
len(main_pool.broken_hosts), len(main_pool.ineligible_hosts))
if spares_needed > 0:
add_msg = 'grow pool by %d DUTs' % spares_needed
elif spares_needed < 0:
add_msg = 'shrink pool by %d DUTs' % -spares_needed
add_msg = 'no change to pool size'
_log_info(dry_run, 'Target is %d working DUTs; %s.',
target_total, add_msg)
'%s %s pool has %d spares available.',
board, main_pool.pool, len(spare_pool.working_hosts))
if spares_needed > len(spare_duts):
_log_error('Not enough spares: need %d, only have %d.',
spares_needed, len(spare_duts))
elif shortfall >= 0:
'%s %s pool will return %d broken DUTs, '
'leaving %d still in the pool.',
board, main_pool.pool,
len(main_pool.broken_hosts) - len(surplus_duts))
'%s %s pool will return %d surplus DUTs, '
'including %d working DUTs.',
board, main_pool.pool,
len(main_pool.broken_hosts) - shortfall,
if (len(main_pool.broken_hosts) > arguments.max_broken and
not arguments.force_rebalance):
_log_error('%s %s pool: Refusing to act on pool with %d broken DUTs.',
board, main_pool.pool, len(main_pool.broken_hosts))
_log_error('Please investigate this board to see if there is a bug ')
_log_error('that is bricking devices. Once you have finished your ')
_log_error('investigation, you can force a rebalance with ')
if not spare_duts and not surplus_duts:
if arguments.verbose:
_log_info(arguments.dry_run, 'No exchange required.')
_exchange_labels(arguments.dry_run, surplus_duts,
spare_pool, main_pool)
_exchange_labels(arguments.dry_run, spare_duts,
main_pool, spare_pool)
def _too_many_broken_boards(inventory, pool, arguments):
Get the inventory of boards and check if too many boards are broken.
@param inventory: inventory object to determine board status inventory.
@param pool: The pool to check on for the board.
@param arguments Parsed command line arguments.
@return True if the number of boards with 1 or more broken duts exceed
max_broken_boards, False otherwise.
# Let's check if we even need to check for this max_broken_boards.
if arguments.force_rebalance or arguments.max_broken_boards == 0:
return False
# Let's get the number of broken duts for the specified pool and
# check that it's less than arguments.max_broken_boards. Or if
# it's not specified, calculate the default number of max broken
# boards based on the total number of boards per pool.
# TODO(kevcheng): Revisit to see if there's a better way to
# calculate the default max_broken_boards.
max_broken_boards = arguments.max_broken_boards
if max_broken_boards is None:
total_num_boards = len(inventory.get_managed_boards(pool=pool))
max_broken_boards = int(_MAX_BROKEN_BOARDS_DEFAULT_RATIO *
'Default max broken boards calculated to be %d for '
'%s pool',
max_broken_boards, pool)
broken_boards = [board for board, counts in inventory.items()
if counts.get_broken(pool) != 0]
num_of_broken_boards = len(broken_boards)
# TODO(kevcheng): Track which boards have broken duts, we can limit the
# number of boards we go through in the main loop with this knowledge.
_log_message('There are %d boards in the %s pool with at least 1 '
'broken DUT (max threshold %d)', num_of_broken_boards,
pool, max_broken_boards)
for broken_board in broken_boards:
return num_of_broken_boards > max_broken_boards
def _parse_command(argv):
"""Parse the command line arguments.
Create an argument parser for this command's syntax, parse the
command line, and return the result of the `ArgumentParser`
`parse_args()` method.
@param argv Standard command line argument vector; `argv[0]` is
assumed to be the command name.
@return Result returned by `ArgumentParser.parse_args()`.
parser = argparse.ArgumentParser(
description='Balance pool shortages from spares on reserve')
count_group = parser.add_mutually_exclusive_group()
count_group.add_argument('-t', '--total', type=int,
metavar='COUNT', default=None,
help='Set the number of DUTs in the '
'pool to the specified count for '
'every BOARD')
count_group.add_argument('-a', '--grow', type=int,
metavar='COUNT', default=None,
help='Add the specified number of DUTs '
'to the pool for every BOARD')
count_group.add_argument('-d', '--shrink', type=int,
metavar='COUNT', default=None,
help='Remove the specified number of DUTs '
'from the pool for every BOARD')
parser.add_argument('-s', '--spare', default=_SPARE_DEFAULT,
help='Pool from which to draw replacement '
'spares (default: pool:%s)' % _SPARE_DEFAULT)
parser.add_argument('-n', '--dry-run', action='store_true',
help='Report actions to take in the form of '
'shell commands')
parser.add_argument('-v', '--verbose', action='store_true',
help='Print more detail about calculations for debug '
parser.add_argument('-m', '--max-broken', default=2, type=int,
help='Only rebalance a pool if it has at most '
'COUNT broken DUTs.')
parser.add_argument('-f', '--force-rebalance', action='store_true',
help='Forcefully rebalance all DUTs in a pool, even '
'if it has a large number of broken DUTs. '
'Before doing this, please investigate whether '
'there is a bug that is bricking devices in the '
parser.add_argument('--all-boards', action='store_true',
help='Rebalance all managed boards. This will do a '
'very expensive check to see how many boards have '
'at least one broken DUT. To bypass that check, '
'set --max-broken-boards to 0.')
default=None, type=int,
help='Only rebalance all boards if number of boards '
'with broken DUTs in the specified pool '
'is less than COUNT.')
help='Name of the pool to balance. Use %s to balance '
'all critical pools' % _ALL_CRITICAL_POOLS)
parser.add_argument('boards', nargs='*',
help='Names of boards to balance.')
arguments = parser.parse_args(argv[1:])
# Error-check arguments.
if not arguments.boards and not arguments.all_boards:
parser.error('No boards specified. To balance all boards, use '
if arguments.boards and arguments.all_boards:
parser.error('Cannot specify boards with --all-boards.')
if (arguments.pool == _ALL_CRITICAL_POOLS and
arguments.spare != _SPARE_DEFAULT):
parser.error('Cannot specify --spare pool to be %s when balancing all '
'critical pools.' % _SPARE_DEFAULT)
return arguments
def main(argv):
"""Standard main routine.
@param argv Command line arguments including `sys.argv[0]`.
def balancer(i, board, pool):
"""Balance the specified board.
@param i The index of the board.
@param board The board name.
@param pool The pool to rebalance for the board.
if i > 0:
_balance_board(arguments, afe, board, pool, start_time, end_time)
arguments = _parse_command(argv)
end_time = time.time()
start_time = end_time - 24 * 60 * 60
afe = frontend.AFE(server=None)
boards = arguments.boards
pools = (lab_inventory.CRITICAL_POOLS
if arguments.pool == _ALL_CRITICAL_POOLS
else [arguments.pool])
board_info = []
if arguments.all_boards:
inventory = lab_inventory.get_inventory(afe)
for pool in pools:
if _too_many_broken_boards(inventory, pool, arguments):
_log_error('Refusing to balance all boards for %s pool, '
'too many boards with at least 1 broken DUT '
'detected.', pool)
boards_in_pool = inventory.get_managed_boards(pool=pool)
current_len_board_info = len(board_info)
board_info.extend([(i + current_len_board_info, board, pool)
for i, board in enumerate(boards_in_pool)])
# We have specified boards with a specified pool, setup the args to the
# balancer properly.
for pool in pools:
current_len_board_info = len(board_info)
board_info.extend([(i + current_len_board_info, board, pool)
for i, board in enumerate(boards)])
parallel.RunTasksInProcessPool(balancer, board_info, processes=8)
except KeyboardInterrupt:
if __name__ == '__main__':