def _check_candidate_fail(group_id, slave_id):
"""Check if the candidate has all the prerequisites to become the new
master.
"""
allowed_status = (_server.MySQLServer.SECONDARY, _server.MySQLServer.SPARE)
group = _server.Group.fetch(group_id)
slave = _retrieve_server(slave_id, group_id)
slave.connect()
if group.master == slave.uuid:
raise _errors.ServerError("Candidate slave (%s) is already master." %
(slave_id, ))
master_issues, why_master_issues = _replication.check_master_issues(slave)
if master_issues:
raise _errors.ServerError("Server (%s) is not a valid candidate slave "
"due to the following reason(s): (%s)." %
(slave.uuid, why_master_issues))
if slave.status not in allowed_status:
raise _errors.ServerError("Server (%s) is faulty." % (slave_id, ))
_events.trigger_within_procedure(WAIT_SLAVE_FAIL, group_id,
str(slave.uuid))
def _check_candidate_fail(group_id, slave_id):
"""Check if the candidate has all the prerequisites to become the new
master.
"""
allowed_status = (_server.MySQLServer.SECONDARY, _server.MySQLServer.SPARE)
group = _server.Group.fetch(group_id)
slave = _retrieve_server(slave_id, group_id)
slave.connect()
if group.master == slave.uuid:
raise _errors.ServerError(
"Candidate slave (%s) is already master." % (slave_id, )
)
master_issues = _replication.check_master_issues(slave)
if master_issues:
raise _errors.ServerError(
"Server (%s) is not a valid candidate slave "
"due to the following reason(s): (%s)." %
(slave.uuid, master_issues)
)
if slave.status not in allowed_status:
raise _errors.ServerError("Server (%s) is faulty." % (slave_id, ))
_events.trigger_within_procedure(WAIT_SLAVE_FAIL, group_id, str(slave.uuid))
def _check_candidate_switch(group_id, slave_id):
"""Check if the candidate has all the features to become the new
master.
"""
allowed_status = (_server.MySQLServer.SECONDARY, _server.MySQLServer.SPARE)
group = _server.Group.fetch(group_id)
if not group.master:
raise _errors.GroupError(
"Group (%s) does not contain a valid "
"master. Please, run a promote or failover." % (group_id, )
)
slave = _retrieve_server(slave_id, group_id)
slave.connect()
if group.master == slave.uuid:
raise _errors.ServerError(
"Candidate slave (%s) is already master." % (slave_id, )
)
master_issues = _replication.check_master_issues(slave)
if master_issues:
raise _errors.ServerError(
"Server (%s) is not a valid candidate slave "
"due to the following reason(s): (%s)." %
(slave.uuid, master_issues)
)
slave_issues = _replication.check_slave_issues(slave)
if slave_issues:
raise _errors.ServerError(
"Server (%s) is not a valid candidate slave "
"due to the following reason: (%s)." %
(slave.uuid, slave_issues)
)
master_uuid = _replication.slave_has_master(slave)
if master_uuid is None or group.master != _uuid.UUID(master_uuid):
raise _errors.GroupError(
"The group's master (%s) is different from the candidate's "
"master (%s)." % (group.master, master_uuid)
)
if slave.status not in allowed_status:
raise _errors.ServerError("Server (%s) is faulty." % (slave_id, ))
_events.trigger_within_procedure(
BLOCK_WRITE_SWITCH, group_id, master_uuid, str(slave.uuid)
)
def _check_candidate_switch(group_id, slave_id):
"""Check if the candidate has all the features to become the new
master.
"""
allowed_status = (_server.MySQLServer.SECONDARY, _server.MySQLServer.SPARE)
group = _server.Group.fetch(group_id)
if not group.master:
raise _errors.GroupError("Group (%s) does not contain a valid "
"master. Please, run a promote or failover." %
(group_id, ))
slave = _retrieve_server(slave_id, group_id)
slave.connect()
if group.master == slave.uuid:
raise _errors.ServerError("Candidate slave (%s) is already master." %
(slave_id, ))
master_issues, why_master_issues = _replication.check_master_issues(slave)
if master_issues:
raise _errors.ServerError("Server (%s) is not a valid candidate slave "
"due to the following reason(s): (%s)." %
(slave.uuid, why_master_issues))
slave_issues, why_slave_issues = _replication.check_slave_issues(slave)
if slave_issues:
raise _errors.ServerError("Server (%s) is not a valid candidate slave "
"due to the following reason: (%s)." %
(slave.uuid, why_slave_issues))
master_uuid = _replication.slave_has_master(slave)
if master_uuid is None or group.master != _uuid.UUID(master_uuid):
raise _errors.GroupError(
"The group's master (%s) is different from the candidate's "
"master (%s)." % (group.master, master_uuid))
if slave.status not in allowed_status:
raise _errors.ServerError("Server (%s) is faulty." % (slave_id, ))
_events.trigger_within_procedure(BLOCK_WRITE_SWITCH, group_id, master_uuid,
str(slave.uuid))
def _do_find_candidate(group_id, event):
"""Find the best candidate in a group that may be used to replace the
current master if there is any.
It chooses the slave that has processed more transactions and may become a
master, e.g. has the binary log enabled. This function does not consider
purged transactions and delays in the slave while picking up a slave.
:param group_id: Group's id from where a candidate will be chosen.
:return: Return the uuid of the best candidate to become a master in the
group.
"""
forbidden_status = (_server.MySQLServer.FAULTY, _server.MySQLServer.SPARE)
group = _server.Group.fetch(group_id)
master_uuid = None
if group.master:
master_uuid = str(group.master)
chosen_uuid = None
chosen_gtid_status = None
for candidate in group.servers():
if master_uuid != str(candidate.uuid) and \
candidate.status not in forbidden_status:
try:
candidate.connect()
gtid_status = candidate.get_gtid_status()
master_issues, why_master_issues = \
_replication.check_master_issues(candidate)
slave_issues = False
why_slave_issues = {}
if event == FIND_CANDIDATE_SWITCH:
slave_issues, why_slave_issues = \
_replication.check_slave_issues(candidate)
has_valid_master = (master_uuid is None or \
_replication.slave_has_master(candidate) == master_uuid)
can_become_master = False
if chosen_gtid_status:
n_trans = 0
try:
n_trans = _replication.get_slave_num_gtid_behind(
candidate, chosen_gtid_status)
except _errors.InvalidGtidError:
pass
if n_trans == 0 and not master_issues and \
has_valid_master and not slave_issues:
chosen_gtid_status = gtid_status
chosen_uuid = str(candidate.uuid)
can_become_master = True
elif not master_issues and has_valid_master and \
not slave_issues:
chosen_gtid_status = gtid_status
chosen_uuid = str(candidate.uuid)
can_become_master = True
if not can_become_master:
_LOGGER.warning(
"Candidate (%s) cannot become a master due to the "
"following reasons: issues to become a "
"master (%s), prerequistes as a slave (%s), valid "
"master (%s).", candidate.uuid, why_master_issues,
why_slave_issues, has_valid_master)
except _errors.DatabaseError as error:
_LOGGER.warning("Error accessing candidate (%s): %s.",
candidate.uuid, error)
if not chosen_uuid:
raise _errors.GroupError(
"There is no valid candidate that can be automatically "
"chosen in group (%s). Please, choose one manually." %
(group_id, ))
return chosen_uuid
def _do_find_candidate(group_id, event):
"""Find the best candidate in a group that may be used to replace the
current master if there is any.
It chooses the slave that has processed more transactions and may become a
master, e.g. has the binary log enabled. This function does not consider
purged transactions and delays in the slave while picking up a slave.
:param group_id: Group's id from where a candidate will be chosen.
:return: Return the uuid of the best candidate to become a master in the
group.
"""
forbidden_status = (_server.MySQLServer.FAULTY, _server.MySQLServer.SPARE)
group = _server.Group.fetch(group_id)
master_uuid = None
if group.master:
master_uuid = str(group.master)
chosen_uuid = None
chosen_gtid_status = None
for candidate in group.servers():
if master_uuid != str(candidate.uuid) and \
candidate.status not in forbidden_status:
try:
candidate.connect()
gtid_status = candidate.get_gtid_status()
master_issues = \
_replication.check_master_issues(candidate)
if event == FIND_CANDIDATE_SWITCH:
slave_issues = \
_replication.check_slave_issues(candidate)
else:
slave_issues = {}
has_valid_master = (master_uuid is None or \
_replication.slave_has_master(candidate) == master_uuid)
can_become_master = False
if chosen_gtid_status:
n_trans = 0
try:
n_trans = _replication.get_slave_num_gtid_behind(
candidate, chosen_gtid_status
)
except _errors.InvalidGtidError:
pass
if n_trans == 0 and not master_issues and \
has_valid_master and not slave_issues:
chosen_gtid_status = gtid_status
chosen_uuid = str(candidate.uuid)
can_become_master = True
elif not master_issues and has_valid_master and \
not slave_issues:
chosen_gtid_status = gtid_status
chosen_uuid = str(candidate.uuid)
can_become_master = True
if not can_become_master:
_LOGGER.warning(
"Candidate (%s) cannot become a master due to the "
"following reasons: issues to become a "
"master (%s), prerequistes as a slave (%s), valid "
"master (%s).", candidate.uuid, master_issues,
slave_issues, has_valid_master
)
except _errors.DatabaseError as error:
_LOGGER.warning(
"Error accessing candidate (%s).", candidate.uuid,
exc_info=error
)
if not chosen_uuid:
raise _errors.GroupError(
"There is no valid candidate that can be automatically "
"chosen in group (%s). Please, choose one manually." %
(group_id, )
)
return chosen_uuid
