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MXS-1703 Reorganize cluster manipulation methods

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Just moving code around.
This commit is contained in:
Esa Korhonen 2018-04-11 14:32:22 +03:00
parent 4ba79e8d49
commit ca9682f042
4 changed files with 380 additions and 366 deletions
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296
server/modules/monitor/mariadbmon/cluster_discovery.cc
View File

@ -950,3 +950,299 @@ static bool check_replicate_wild_ignore_table(MXS_MONITORED_SERVER* database)
}
return rval;
}
/**
* @brief Check whether standalone master conditions have been met
*
* This function checks whether all the conditions to use a standalone master are met. For this to happen,
* only one server must be available and other servers must have passed the configured tolerance level of
* failures.
*
* @param db Monitor servers
*
* @return True if standalone master should be used
*/
bool MariaDBMonitor::standalone_master_required(MXS_MONITORED_SERVER *db)
{
int candidates = 0;
while (db)
{
if (SERVER_IS_RUNNING(db->server))
{
candidates++;
MariaDBServer *server_info = get_server_info(db);
if (server_info->read_only || server_info->slave_configured || candidates > 1)
{
return false;
}
}
else if (db->mon_err_count < m_failcount)
{
return false;
}
db = db->next;
}
return candidates == 1;
}
/**
* @brief Use standalone master
*
* This function assigns the last remaining server the master status and sets all other servers into
* maintenance mode. By setting the servers into maintenance mode, we prevent any possible conflicts when
* the failed servers come back up.
*
* @param db Monitor servers
*/
bool MariaDBMonitor::set_standalone_master(MXS_MONITORED_SERVER *db)
{
bool rval = false;
while (db)
{
if (SERVER_IS_RUNNING(db->server))
{
if (!SERVER_IS_MASTER(db->server) && m_warn_set_standalone_master)
{
MXS_WARNING("Setting standalone master, server '%s' is now the master.%s",
db->server->unique_name,
m_allow_cluster_recovery ?
"" : " All other servers are set into maintenance mode.");
m_warn_set_standalone_master = false;
}
server_clear_set_status(db->server, SERVER_SLAVE, SERVER_MASTER | SERVER_STALE_STATUS);
monitor_set_pending_status(db, SERVER_MASTER | SERVER_STALE_STATUS);
monitor_clear_pending_status(db, SERVER_SLAVE);
m_master = db;
rval = true;
}
else if (!m_allow_cluster_recovery)
{
server_set_status_nolock(db->server, SERVER_MAINT);
monitor_set_pending_status(db, SERVER_MAINT);
}
db = db->next;
}
return rval;
}
/**
* Monitor a server. Should be moved to the server class later on.
*
* @param server The server
*/
void MariaDBMonitor::monitor_one_server(MariaDBServer& server)
{
MXS_MONITORED_SERVER* ptr = server.server_base;
ptr->mon_prev_status = ptr->server->status;
/* copy server status into monitor pending_status */
ptr->pending_status = ptr->server->status;
/* monitor current node */
monitor_database(get_server_info(ptr));
/* reset the slave list of current node */
memset(&ptr->server->slaves, 0, sizeof(ptr->server->slaves));
if (mon_status_changed(ptr))
{
if (SRV_MASTER_STATUS(ptr->mon_prev_status))
{
/** Master failed, can't recover */
MXS_NOTICE("Server [%s]:%d lost the master status.",
ptr->server->name,
ptr->server->port);
}
}
if (mon_status_changed(ptr))
{
#if defined(SS_DEBUG)
MXS_INFO("Backend server [%s]:%d state : %s",
ptr->server->name,
ptr->server->port,
STRSRVSTATUS(ptr->server));
#else
MXS_DEBUG("Backend server [%s]:%d state : %s",
ptr->server->name,
ptr->server->port,
STRSRVSTATUS(ptr->server));
#endif
}
if (SERVER_IS_DOWN(ptr->server))
{
/** Increase this server'e error count */
ptr->mon_err_count += 1;
}
else
{
/** Reset this server's error count */
ptr->mon_err_count = 0;
}
}
/**
* Compute replication tree, find root master.
*
* @return Found master server or NULL
*/
MariaDBServer* MariaDBMonitor::find_root_master()
{
MXS_MONITORED_SERVER* found_root_master = NULL;
const int num_servers = m_servers.size();
/* if only one server is configured, that's is Master */
if (num_servers == 1)
{
auto mon_server = m_servers[0].server_base;
if (SERVER_IS_RUNNING(mon_server->server))
{
mon_server->server->depth = 0;
/* status cleanup */
monitor_clear_pending_status(mon_server, SERVER_SLAVE);
/* master status set */
monitor_set_pending_status(mon_server, SERVER_MASTER);
mon_server->server->depth = 0;
m_master = mon_server;
found_root_master = mon_server;
}
}
else
{
/* Compute the replication tree */
if (m_mysql51_replication)
{
found_root_master = build_mysql51_replication_tree();
}
else
{
found_root_master = get_replication_tree();
}
}
if (m_detect_multimaster && num_servers > 0)
{
/** Find all the master server cycles in the cluster graph. If
multiple masters are found, the servers with the read_only
variable set to ON will be assigned the slave status. */
find_graph_cycles();
}
return found_root_master ? get_server_info(found_root_master) : NULL;
}
/**
* Test if server is a relay master and assign status if yes.
*
* @param candidate The server to assign
*/
void MariaDBMonitor::assign_relay_master(MariaDBServer& candidate)
{
MXS_MONITORED_SERVER* ptr = candidate.server_base;
if (ptr->server->node_id > 0 && ptr->server->master_id > 0 &&
getSlaveOfNodeId(ptr->server->node_id, REJECT_DOWN) &&
getServerByNodeId(ptr->server->master_id) &&
(!m_detect_multimaster || candidate.group == 0))
{
/** This server is both a slave and a master i.e. a relay master */
monitor_set_pending_status(ptr, SERVER_RELAY_MASTER);
monitor_clear_pending_status(ptr, SERVER_MASTER);
}
}
/**
* Update serve states of a single server
*
* @param db_server Server to update
* @param root_master_server The current best master
*/
void MariaDBMonitor::update_server_states(MariaDBServer& db_server, MariaDBServer* root_master_server)
{
MXS_MONITORED_SERVER* ptr = db_server.server_base;
MXS_MONITORED_SERVER* root_master = root_master_server ? root_master_server->server_base : NULL;
if (!SERVER_IN_MAINT(ptr->server))
{
MariaDBServer *serv_info = get_server_info(ptr);
/** If "detect_stale_master" option is On, let's use the previous master.
*
* Multi-master mode detects the stale masters in find_graph_cycles().
*
* TODO: If a stale master goes down and comes back up, it loses
* the master status. An adequate solution would be to promote
* the stale master as a real master if it is the last running server.
*/
if (m_detect_stale_master && root_master && !m_detect_multimaster &&
(strcmp(ptr->server->name, root_master->server->name) == 0 &&
ptr->server->port == root_master->server->port) &&
(ptr->server->status & SERVER_MASTER) &&
!(ptr->pending_status & SERVER_MASTER) &&
!serv_info->read_only)
{
/**
* In this case server->status will not be updated from pending_status
* Set the STALE bit for this server in server struct
*/
server_set_status_nolock(ptr->server, SERVER_STALE_STATUS | SERVER_MASTER);
monitor_set_pending_status(ptr, SERVER_STALE_STATUS | SERVER_MASTER);
/** Log the message only if the master server didn't have
* the stale master bit set */
if ((ptr->mon_prev_status & SERVER_STALE_STATUS) == 0)
{
MXS_WARNING("All slave servers under the current master "
"server have been lost. Assigning Stale Master"
" status to the old master server '%s' (%s:%i).",
ptr->server->unique_name, ptr->server->name,
ptr->server->port);
}
}
if (m_detect_stale_slave)
{
unsigned int bits = SERVER_SLAVE | SERVER_RUNNING;
if ((ptr->mon_prev_status & bits) == bits &&
root_master && SERVER_IS_MASTER(root_master->server))
{
/** Slave with a running master, assign stale slave candidacy */
if ((ptr->pending_status & bits) == bits)
{
monitor_set_pending_status(ptr, SERVER_STALE_SLAVE);
}
/** Server lost slave when a master is available, remove
* stale slave candidacy */
else if ((ptr->pending_status & bits) == SERVER_RUNNING)
{
monitor_clear_pending_status(ptr, SERVER_STALE_SLAVE);
}
}
/** If this server was a stale slave candidate, assign
* slave status to it */
else if (ptr->mon_prev_status & SERVER_STALE_SLAVE &&
ptr->pending_status & SERVER_RUNNING &&
// Master is down
(!root_master || !SERVER_IS_MASTER(root_master->server) ||
// Master just came up
(SERVER_IS_MASTER(root_master->server) &&
(root_master->mon_prev_status & SERVER_MASTER) == 0)))
{
monitor_set_pending_status(ptr, SERVER_SLAVE);
}
else if (root_master == NULL && serv_info->slave_configured)
{
monitor_set_pending_status(ptr, SERVER_SLAVE);
}
}
ptr->server->status = ptr->pending_status;
}
}

8
server/modules/monitor/mariadbmon/cluster_manipulation.cc
View File

@ -1531,6 +1531,14 @@ bool MariaDBMonitor::mon_process_failover(bool* cluster_modified_out)
return rval;
}
/**
* Check if server is using gtid replication.
*
* @param mon_server Server to check
* @param error_out Error output
* @return True if using gtid-replication. False if not, or if server is not a slave or otherwise does
* not have a gtid_IO_Pos.
*/
bool MariaDBMonitor::uses_gtid(MXS_MONITORED_SERVER* mon_server, json_t** error_out)
{
bool rval = false;

300
server/modules/monitor/mariadbmon/mariadbmon.cc
View File

@ -86,12 +86,22 @@ void MariaDBMonitor::init_server_info()
}
}
/**
* Get monitor-specific server info for the monitored server.
*
* @param handle
* @param db Server to get info for. Must be a valid server or function crashes.
* @return The server info.
*/
MariaDBServer* MariaDBMonitor::get_server_info(MXS_MONITORED_SERVER* db)
{
ss_dassert(m_server_info.count(db) == 1); // Should always exist in the map
return m_server_info[db];
}
/**
* Constant version of get_server_info().
*/
const MariaDBServer* MariaDBMonitor::get_server_info(const MXS_MONITORED_SERVER* db) const
{
return const_cast<MariaDBMonitor*>(this)->get_server_info(const_cast<MXS_MONITORED_SERVER*>(db));
@ -359,87 +369,6 @@ json_t* MariaDBMonitor::diagnostics_json() const
return rval;
}
/**
* @brief Check whether standalone master conditions have been met
*
* This function checks whether all the conditions to use a standalone master are met. For this to happen,
* only one server must be available and other servers must have passed the configured tolerance level of
* failures.
*
* @param db Monitor servers
*
* @return True if standalone master should be used
*/
bool MariaDBMonitor::standalone_master_required(MXS_MONITORED_SERVER *db)
{
int candidates = 0;
while (db)
{
if (SERVER_IS_RUNNING(db->server))
{
candidates++;
MariaDBServer *server_info = get_server_info(db);
if (server_info->read_only || server_info->slave_configured || candidates > 1)
{
return false;
}
}
else if (db->mon_err_count < m_failcount)
{
return false;
}
db = db->next;
}
return candidates == 1;
}
/**
* @brief Use standalone master
*
* This function assigns the last remaining server the master status and sets all other servers into
* maintenance mode. By setting the servers into maintenance mode, we prevent any possible conflicts when
* the failed servers come back up.
*
* @param db Monitor servers
*/
bool MariaDBMonitor::set_standalone_master(MXS_MONITORED_SERVER *db)
{
bool rval = false;
while (db)
{
if (SERVER_IS_RUNNING(db->server))
{
if (!SERVER_IS_MASTER(db->server) && m_warn_set_standalone_master)
{
MXS_WARNING("Setting standalone master, server '%s' is now the master.%s",
db->server->unique_name,
m_allow_cluster_recovery ?
"" : " All other servers are set into maintenance mode.");
m_warn_set_standalone_master = false;
}
server_clear_set_status(db->server, SERVER_SLAVE, SERVER_MASTER | SERVER_STALE_STATUS);
monitor_set_pending_status(db, SERVER_MASTER | SERVER_STALE_STATUS);
monitor_clear_pending_status(db, SERVER_SLAVE);
m_master = db;
rval = true;
}
else if (!m_allow_cluster_recovery)
{
server_set_status_nolock(db->server, SERVER_MAINT);
monitor_set_pending_status(db, SERVER_MAINT);
}
db = db->next;
}
return rval;
}
void MariaDBMonitor::main_loop()
{
m_status = MXS_MONITOR_RUNNING;
@ -608,113 +537,6 @@ void MariaDBMonitor::main_loop()
m_status = MXS_MONITOR_STOPPED;
}
/**
* Monitor a server. Should be moved to the server class later on.
*
* @param server The server
*/
void MariaDBMonitor::monitor_one_server(MariaDBServer& server)
{
MXS_MONITORED_SERVER* ptr = server.server_base;
ptr->mon_prev_status = ptr->server->status;
/* copy server status into monitor pending_status */
ptr->pending_status = ptr->server->status;
/* monitor current node */
monitor_database(get_server_info(ptr));
/* reset the slave list of current node */
memset(&ptr->server->slaves, 0, sizeof(ptr->server->slaves));
if (mon_status_changed(ptr))
{
if (SRV_MASTER_STATUS(ptr->mon_prev_status))
{
/** Master failed, can't recover */
MXS_NOTICE("Server [%s]:%d lost the master status.",
ptr->server->name,
ptr->server->port);
}
}
if (mon_status_changed(ptr))
{
#if defined(SS_DEBUG)
MXS_INFO("Backend server [%s]:%d state : %s",
ptr->server->name,
ptr->server->port,
STRSRVSTATUS(ptr->server));
#else
MXS_DEBUG("Backend server [%s]:%d state : %s",
ptr->server->name,
ptr->server->port,
STRSRVSTATUS(ptr->server));
#endif
}
if (SERVER_IS_DOWN(ptr->server))
{
/** Increase this server'e error count */
ptr->mon_err_count += 1;
}
else
{
/** Reset this server's error count */
ptr->mon_err_count = 0;
}
}
/**
* Compute replication tree, find root master.
*
* @return Found master server or NULL
*/
MariaDBServer* MariaDBMonitor::find_root_master()
{
MXS_MONITORED_SERVER* found_root_master = NULL;
const int num_servers = m_servers.size();
/* if only one server is configured, that's is Master */
if (num_servers == 1)
{
auto mon_server = m_servers[0].server_base;
if (SERVER_IS_RUNNING(mon_server->server))
{
mon_server->server->depth = 0;
/* status cleanup */
monitor_clear_pending_status(mon_server, SERVER_SLAVE);
/* master status set */
monitor_set_pending_status(mon_server, SERVER_MASTER);
mon_server->server->depth = 0;
m_master = mon_server;
found_root_master = mon_server;
}
}
else
{
/* Compute the replication tree */
if (m_mysql51_replication)
{
found_root_master = build_mysql51_replication_tree();
}
else
{
found_root_master = get_replication_tree();
}
}
if (m_detect_multimaster && num_servers > 0)
{
/** Find all the master server cycles in the cluster graph. If
multiple masters are found, the servers with the read_only
variable set to ON will be assigned the slave status. */
find_graph_cycles();
}
return found_root_master ? get_server_info(found_root_master) : NULL;
}
void MariaDBMonitor::update_gtid_domain()
{
MariaDBServer* master_info = get_server_info(m_master);
@ -763,108 +585,6 @@ void MariaDBMonitor::update_external_master()
}
}
/**
* TODO: Move to MariaDBServer.
*
* @param serv_info
*/
void MariaDBMonitor::assign_relay_master(MariaDBServer& serv_info)
{
MXS_MONITORED_SERVER* ptr = serv_info.server_base;
if (ptr->server->node_id > 0 && ptr->server->master_id > 0 &&
getSlaveOfNodeId(ptr->server->node_id, REJECT_DOWN) &&
getServerByNodeId(ptr->server->master_id) &&
(!m_detect_multimaster || serv_info.group == 0))
{
/** This server is both a slave and a master i.e. a relay master */
monitor_set_pending_status(ptr, SERVER_RELAY_MASTER);
monitor_clear_pending_status(ptr, SERVER_MASTER);
}
}
void MariaDBMonitor::update_server_states(MariaDBServer& db_server, MariaDBServer* root_master_server)
{
MXS_MONITORED_SERVER* ptr = db_server.server_base;
MXS_MONITORED_SERVER* root_master = root_master_server ? root_master_server->server_base : NULL;
if (!SERVER_IN_MAINT(ptr->server))
{
MariaDBServer *serv_info = get_server_info(ptr);
/** If "detect_stale_master" option is On, let's use the previous master.
*
* Multi-master mode detects the stale masters in find_graph_cycles().
*
* TODO: If a stale master goes down and comes back up, it loses
* the master status. An adequate solution would be to promote
* the stale master as a real master if it is the last running server.
*/
if (m_detect_stale_master && root_master && !m_detect_multimaster &&
(strcmp(ptr->server->name, root_master->server->name) == 0 &&
ptr->server->port == root_master->server->port) &&
(ptr->server->status & SERVER_MASTER) &&
!(ptr->pending_status & SERVER_MASTER) &&
!serv_info->read_only)
{
/**
* In this case server->status will not be updated from pending_status
* Set the STALE bit for this server in server struct
*/
server_set_status_nolock(ptr->server, SERVER_STALE_STATUS | SERVER_MASTER);
monitor_set_pending_status(ptr, SERVER_STALE_STATUS | SERVER_MASTER);
/** Log the message only if the master server didn't have
* the stale master bit set */
if ((ptr->mon_prev_status & SERVER_STALE_STATUS) == 0)
{
MXS_WARNING("All slave servers under the current master "
"server have been lost. Assigning Stale Master"
" status to the old master server '%s' (%s:%i).",
ptr->server->unique_name, ptr->server->name,
ptr->server->port);
}
}
if (m_detect_stale_slave)
{
unsigned int bits = SERVER_SLAVE | SERVER_RUNNING;
if ((ptr->mon_prev_status & bits) == bits &&
root_master && SERVER_IS_MASTER(root_master->server))
{
/** Slave with a running master, assign stale slave candidacy */
if ((ptr->pending_status & bits) == bits)
{
monitor_set_pending_status(ptr, SERVER_STALE_SLAVE);
}
/** Server lost slave when a master is available, remove
* stale slave candidacy */
else if ((ptr->pending_status & bits) == SERVER_RUNNING)
{
monitor_clear_pending_status(ptr, SERVER_STALE_SLAVE);
}
}
/** If this server was a stale slave candidate, assign
* slave status to it */
else if (ptr->mon_prev_status & SERVER_STALE_SLAVE &&
ptr->pending_status & SERVER_RUNNING &&
// Master is down
(!root_master || !SERVER_IS_MASTER(root_master->server) ||
// Master just came up
(SERVER_IS_MASTER(root_master->server) &&
(root_master->mon_prev_status & SERVER_MASTER) == 0)))
{
monitor_set_pending_status(ptr, SERVER_SLAVE);
}
else if (root_master == NULL && serv_info->slave_configured)
{
monitor_set_pending_status(ptr, SERVER_SLAVE);
}
}
ptr->server->status = ptr->pending_status;
}
}
void MariaDBMonitor::measure_replication_lag(MariaDBServer* root_master_server)
{
MXS_MONITORED_SERVER* root_master = root_master_server ? root_master_server->server_base : NULL;

142
server/modules/monitor/mariadbmon/mariadbmon.hh
View File

@ -108,30 +108,6 @@ public:
*/
bool manual_rejoin(SERVER* rejoin_server, json_t** output);
/**
* Check if server is using gtid replication.
*
* @param mon_server Server to check
* @param error_out Error output
* @return True if using gtid-replication. False if not, or if server is not a slave or otherwise does
* not have a gtid_IO_Pos.
*/
bool uses_gtid(MXS_MONITORED_SERVER* mon_server, json_t** error_out);
/**
* Get monitor-specific server info for the monitored server.
*
* @param handle
* @param db Server to get info for. Must be a valid server or function crashes.
* @return The server info.
*/
MariaDBServer* get_server_info(MXS_MONITORED_SERVER* db);
/**
* Constant version of get_server_info().
*/
const MariaDBServer* get_server_info(const MXS_MONITORED_SERVER* db) const;
private:
MXS_MONITOR* m_monitor_base; /**< Generic monitor object */
THREAD m_thread; /**< Monitor thread */
@ -182,72 +158,86 @@ private:
REJECT_DOWN
};
// Base methods
MariaDBMonitor(MXS_MONITOR* monitor_base);
~MariaDBMonitor();
bool load_config_params(const MXS_CONFIG_PARAMETER* params);
bool failover_wait_relay_log(MXS_MONITORED_SERVER* new_master, int seconds_remaining, json_t** err_out);
bool switchover_demote_master(MXS_MONITORED_SERVER* current_master, MariaDBServer* info,
json_t** err_out);
bool switchover_wait_slaves_catchup(const ServerRefArray& slaves, const GtidList& gtid, int total_timeout,
int read_timeout, json_t** err_out);
bool wait_cluster_stabilization(MariaDBServer* new_master, const ServerRefArray& slaves,
int seconds_remaining);
bool switchover_check_preferred_master(MXS_MONITORED_SERVER* preferred, json_t** err_out);
bool promote_new_master(MXS_MONITORED_SERVER* new_master, json_t** err_out);
MariaDBServer* select_new_master(ServerRefArray* slaves_out, json_t** err_out);
bool server_is_excluded(const MXS_MONITORED_SERVER* server);
bool is_candidate_better(const MariaDBServer* current_best_info, const MariaDBServer* candidate_info,
uint32_t gtid_domain);
MariaDBServer* update_slave_info(MXS_MONITORED_SERVER* server);
void init_server_info();
bool slave_receiving_events();
void monitor_database(MariaDBServer* param_db);
bool standalone_master_required(MXS_MONITORED_SERVER *db);
bool set_standalone_master(MXS_MONITORED_SERVER *db);
bool failover_not_possible();
std::string generate_change_master_cmd(const std::string& master_host, int master_port);
int redirect_slaves(MariaDBServer* new_master, const ServerRefArray& slaves,
ServerRefArray* redirected_slaves);
bool load_config_params(const MXS_CONFIG_PARAMETER* params);
bool set_replication_credentials(const MXS_CONFIG_PARAMETER* params);
bool start_external_replication(MXS_MONITORED_SERVER* new_master, json_t** err_out);
bool switchover_start_slave(MXS_MONITORED_SERVER* old_master, SERVER* new_master);
bool redirect_one_slave(MXS_MONITORED_SERVER* slave, const char* change_cmd);
bool get_joinable_servers(ServerRefArray* output);
bool join_cluster(MXS_MONITORED_SERVER* server, const char* change_cmd);
MariaDBServer* get_server_info(MXS_MONITORED_SERVER* db);
const MariaDBServer* get_server_info(const MXS_MONITORED_SERVER* db) const;
// Cluster discovery and status assignment methods
void monitor_one_server(MariaDBServer& server);
void monitor_database(MariaDBServer* param_db);
void monitor_mysql_db(MariaDBServer *serv_info);
MariaDBServer* find_root_master();
MXS_MONITORED_SERVER* get_replication_tree();
MXS_MONITORED_SERVER* build_mysql51_replication_tree();
void find_graph_cycles();
void update_server_states(MariaDBServer& db_server, MariaDBServer* root_master);
bool standalone_master_required(MXS_MONITORED_SERVER* db);
bool set_standalone_master(MXS_MONITORED_SERVER* db);
void assign_relay_master(MariaDBServer& serv_info);
void log_master_changes(MariaDBServer* root_master, int* log_no_master);
void update_gtid_domain();
void update_external_master();
void set_master_heartbeat(MXS_MONITORED_SERVER *);
void set_slave_heartbeat(MXS_MONITORED_SERVER *);
MXS_MONITORED_SERVER* build_mysql51_replication_tree();
MXS_MONITORED_SERVER* get_replication_tree();
void monitor_mysql_db(MariaDBServer *serv_info);
bool do_switchover(MariaDBServer** current_master, MariaDBServer** new_master, json_t** err_out);
bool do_failover(json_t** err_out);
uint32_t do_rejoin(const ServerRefArray& joinable_servers);
bool mon_process_failover(bool* cluster_modified_out);
bool server_is_rejoin_suspect(MariaDBServer* rejoin_cand, MariaDBServer* master, json_t** output);
bool cluster_can_be_joined();
bool failover_check(json_t** error_out);
void disable_setting(const char* setting);
void measure_replication_lag(MariaDBServer* root_master);
void check_maxscale_schema_replication();
MXS_MONITORED_SERVER* getServerByNodeId(long);
MXS_MONITORED_SERVER* getSlaveOfNodeId(long, slave_down_setting_t);
// Switchover methods
bool switchover_check(SERVER* new_master, SERVER* current_master,
MariaDBServer** new_master_out, MariaDBServer** current_master_out,
json_t** error_out);
bool switchover_check_new(const MXS_MONITORED_SERVER* monitored_server, json_t** error);
bool switchover_check_current(const MXS_MONITORED_SERVER* suggested_curr_master,
json_t** error_out) const;
bool can_replicate_from(MariaDBServer* slave_cand, MariaDBServer* master);
void monitor_one_server(MariaDBServer& server);
MariaDBServer* find_root_master();
void update_gtid_domain();
void update_external_master();
void assign_relay_master(MariaDBServer& serv_info);
void update_server_states(MariaDBServer& db_server, MariaDBServer* root_master);
void log_master_changes(MariaDBServer* root_master, int* log_no_master);
bool do_switchover(MariaDBServer** current_master, MariaDBServer** new_master, json_t** err_out);
bool switchover_check_preferred_master(MXS_MONITORED_SERVER* preferred, json_t** err_out);
bool switchover_demote_master(MXS_MONITORED_SERVER* current_master, MariaDBServer* info,
json_t** err_out);
bool switchover_wait_slaves_catchup(const ServerRefArray& slaves, const GtidList& gtid, int total_timeout,
int read_timeout, json_t** err_out);
bool switchover_start_slave(MXS_MONITORED_SERVER* old_master, SERVER* new_master);
// Failover methods
void handle_auto_failover(bool* failover_performed);
void measure_replication_lag(MariaDBServer* root_master);
bool failover_not_possible();
bool slave_receiving_events();
bool mon_process_failover(bool* cluster_modified_out);
bool failover_check(json_t** error_out);
bool do_failover(json_t** err_out);
bool failover_wait_relay_log(MXS_MONITORED_SERVER* new_master, int seconds_remaining, json_t** err_out);
// Rejoin methods
bool cluster_can_be_joined();
void handle_auto_rejoin();
void find_graph_cycles();
void check_maxscale_schema_replication();
MXS_MONITORED_SERVER* getServerByNodeId(long);
MXS_MONITORED_SERVER* getSlaveOfNodeId(long, slave_down_setting_t);
bool get_joinable_servers(ServerRefArray* output);
bool server_is_rejoin_suspect(MariaDBServer* rejoin_cand, MariaDBServer* master, json_t** output);
bool can_replicate_from(MariaDBServer* slave_cand, MariaDBServer* master);
uint32_t do_rejoin(const ServerRefArray& joinable_servers);
bool join_cluster(MXS_MONITORED_SERVER* server, const char* change_cmd);
// Methods common to failover/switchover/rejoin
bool uses_gtid(MXS_MONITORED_SERVER* mon_server, json_t** error_out);
MariaDBServer* select_new_master(ServerRefArray* slaves_out, json_t** err_out);
MariaDBServer* update_slave_info(MXS_MONITORED_SERVER* server);
bool server_is_excluded(const MXS_MONITORED_SERVER* server);
bool is_candidate_better(const MariaDBServer* current_best_info, const MariaDBServer* candidate_info,
uint32_t gtid_domain);
bool promote_new_master(MXS_MONITORED_SERVER* new_master, json_t** err_out);
int redirect_slaves(MariaDBServer* new_master, const ServerRefArray& slaves,
ServerRefArray* redirected_slaves);
bool redirect_one_slave(MXS_MONITORED_SERVER* slave, const char* change_cmd);
std::string generate_change_master_cmd(const std::string& master_host, int master_port);
bool start_external_replication(MXS_MONITORED_SERVER* new_master, json_t** err_out);
bool wait_cluster_stabilization(MariaDBServer* new_master, const ServerRefArray& slaves,
int seconds_remaining);
void disable_setting(const char* setting);
};
/**