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MaxScale/server/modules/monitor/mariadbmon/mariadbmon.cc
Johan Wikman 32c7ae2f9f MXS-1775 Inherit MariaDBMonitor from mxs::MonitorInstance 
Start/stop now provided by MonitorInstance. The thread main
function is now virtual and overriden by MariaDBMonitor. Some
additional refactoring is necessary in order to be able to allow
MonitorInstance to handle the main loop.
2018-06-01 13:48:15 +03:00

1128 lines
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/*
* Copyright (c) 2016 MariaDB Corporation Ab
*
* Use of this software is governed by the Business Source License included
* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
*
* Change Date: 2020-01-01
*
* On the date above, in accordance with the Business Source License, use
* of this software will be governed by version 2 or later of the General
* Public License.
*/
/**
* @file A MariaDB replication cluster monitor
*/
#include "mariadbmon.hh"
#include <inttypes.h>
#include <sstream>
#include <maxscale/alloc.h>
#include <maxscale/dcb.h>
#include <maxscale/debug.h>
#include <maxscale/modulecmd.h>
#include <maxscale/mysql_utils.h>
#include <maxscale/secrets.h>
#include <maxscale/utils.h>
// TODO: For monitor_add_parameters
#include "../../../core/internal/monitor.h"
using std::string;
// Config parameter names
const char * const CN_AUTO_FAILOVER = "auto_failover";
const char * const CN_PROMOTION_SQL_FILE = "promotion_sql_file";
const char * const CN_DEMOTION_SQL_FILE = "demotion_sql_file";
static const char CN_AUTO_REJOIN[] = "auto_rejoin";
static const char CN_FAILCOUNT[] = "failcount";
static const char CN_ENFORCE_READONLY[] = "enforce_read_only_slaves";
static const char CN_NO_PROMOTE_SERVERS[] = "servers_no_promotion";
static const char CN_FAILOVER_TIMEOUT[] = "failover_timeout";
static const char CN_SWITCHOVER_TIMEOUT[] = "switchover_timeout";
// Parameters for master failure verification and timeout
static const char CN_VERIFY_MASTER_FAILURE[] = "verify_master_failure";
static const char CN_MASTER_FAILURE_TIMEOUT[] = "master_failure_timeout";
// Replication credentials parameters for failover/switchover/join
static const char CN_REPLICATION_USER[] = "replication_user";
static const char CN_REPLICATION_PASSWORD[] = "replication_password";
MariaDBMonitor::MariaDBMonitor(MXS_MONITOR* monitor)
: maxscale::MonitorInstance(monitor)
, m_id(config_get_global_options()->id)
, m_master_gtid_domain(GTID_DOMAIN_UNKNOWN)
, m_external_master_port(PORT_UNKNOWN)
, m_cluster_modified(true)
, m_warn_set_standalone_master(true)
{}
MariaDBMonitor::~MariaDBMonitor()
{
clear_server_info();
}
/**
* Reset and initialize server arrays and related data.
*/
void MariaDBMonitor::reset_server_info()
{
// If this monitor is being restarted, the server data needs to be freed.
clear_server_info();
// Next, initialize the data.
for (auto mon_server = m_monitor->monitored_servers; mon_server; mon_server = mon_server->next)
{
m_servers.push_back(new MariaDBServer(mon_server));
}
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
auto mon_server = (*iter)->m_server_base;
ss_dassert(m_server_info.count(mon_server) == 0);
ServerInfoMap::value_type new_val(mon_server, *iter);
m_server_info.insert(new_val);
}
}
void MariaDBMonitor::clear_server_info()
{
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
delete *iter;
}
// All MariaDBServer*:s are now invalid, as well as any dependant data.
m_servers.clear();
m_server_info.clear();
m_excluded_servers.clear();
m_master = NULL;
m_master_gtid_domain = GTID_DOMAIN_UNKNOWN;
m_external_master_host.clear();
m_external_master_port = PORT_UNKNOWN;
}
/**
* 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];
}
bool MariaDBMonitor::set_replication_credentials(const MXS_CONFIG_PARAMETER* params)
{
bool rval = false;
string repl_user = config_get_string(params, CN_REPLICATION_USER);
string repl_pw = config_get_string(params, CN_REPLICATION_PASSWORD);
if (repl_user.empty() && repl_pw.empty())
{
// No replication credentials defined, use monitor credentials
repl_user = m_monitor->user;
repl_pw = m_monitor->password;
}
if (!repl_user.empty() && !repl_pw.empty())
{
m_replication_user = repl_user;
char* decrypted = decrypt_password(repl_pw.c_str());
m_replication_password = decrypted;
MXS_FREE(decrypted);
rval = true;
}
return rval;
}
MariaDBMonitor* MariaDBMonitor::create(MXS_MONITOR *monitor)
{
return new MariaDBMonitor(monitor);
}
/**
* Load config parameters
*
* @param params Config parameters
* @return True if settings are ok
*/
bool MariaDBMonitor::configure(const MXS_CONFIG_PARAMETER* params)
{
/* Reset all monitored state info. The server dependent values must be reset as servers could have been
* added, removed and modified. */
reset_server_info();
m_detect_stale_master = config_get_bool(params, "detect_stale_master");
m_detect_stale_slave = config_get_bool(params, "detect_stale_slave");
m_detect_replication_lag = config_get_bool(params, "detect_replication_lag");
m_detect_multimaster = config_get_bool(params, "multimaster");
m_ignore_external_masters = config_get_bool(params, "ignore_external_masters");
m_detect_standalone_master = config_get_bool(params, "detect_standalone_master");
m_failcount = config_get_integer(params, CN_FAILCOUNT);
m_allow_cluster_recovery = config_get_bool(params, "allow_cluster_recovery");
m_script = config_get_string(params, "script");
m_events = config_get_enum(params, "events", mxs_monitor_event_enum_values);
m_failover_timeout = config_get_integer(params, CN_FAILOVER_TIMEOUT);
m_switchover_timeout = config_get_integer(params, CN_SWITCHOVER_TIMEOUT);
m_auto_failover = config_get_bool(params, CN_AUTO_FAILOVER);
m_auto_rejoin = config_get_bool(params, CN_AUTO_REJOIN);
m_enforce_read_only_slaves = config_get_bool(params, CN_ENFORCE_READONLY);
m_verify_master_failure = config_get_bool(params, CN_VERIFY_MASTER_FAILURE);
m_master_failure_timeout = config_get_integer(params, CN_MASTER_FAILURE_TIMEOUT);
m_promote_sql_file = config_get_string(params, CN_PROMOTION_SQL_FILE);
m_demote_sql_file = config_get_string(params, CN_DEMOTION_SQL_FILE);
m_excluded_servers.clear();
MXS_MONITORED_SERVER** excluded_array = NULL;
int n_excluded = mon_config_get_servers(params, CN_NO_PROMOTE_SERVERS, m_monitor, &excluded_array);
for (int i = 0; i < n_excluded; i++)
{
m_excluded_servers.push_back(get_server_info(excluded_array[i]));
}
MXS_FREE(excluded_array);
bool settings_ok = true;
if (!check_sql_files())
{
settings_ok = false;
}
if (!set_replication_credentials(params))
{
MXS_ERROR("Both '%s' and '%s' must be defined", CN_REPLICATION_USER, CN_REPLICATION_PASSWORD);
settings_ok = false;
}
return settings_ok;
}
void MariaDBMonitor::diagnostics(DCB *dcb) const
{
dcb_printf(dcb, "Automatic failover: %s\n", m_auto_failover ? "Enabled" : "Disabled");
dcb_printf(dcb, "Failcount: %d\n", m_failcount);
dcb_printf(dcb, "Failover timeout: %u\n", m_failover_timeout);
dcb_printf(dcb, "Switchover timeout: %u\n", m_switchover_timeout);
dcb_printf(dcb, "Automatic rejoin: %s\n", m_auto_rejoin ? "Enabled" : "Disabled");
dcb_printf(dcb, "Enforce read-only: %s\n", m_enforce_read_only_slaves ?
"Enabled" : "Disabled");
dcb_printf(dcb, "MaxScale monitor ID: %lu\n", m_id);
dcb_printf(dcb, "Detect replication lag: %s\n", (m_detect_replication_lag) ? "Enabled" : "Disabled");
dcb_printf(dcb, "Detect stale master: %s\n", (m_detect_stale_master == 1) ?
"Enabled" : "Disabled");
if (m_excluded_servers.size() > 0)
{
dcb_printf(dcb, "Non-promotable servers (failover): ");
dcb_printf(dcb, "%s\n", monitored_servers_to_string(m_excluded_servers).c_str());
}
dcb_printf(dcb, "\nServer information:\n-------------------\n\n");
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
string server_info = (*iter)->diagnostics(m_detect_multimaster) + "\n";
dcb_printf(dcb, "%s", server_info.c_str());
}
}
json_t* MariaDBMonitor::diagnostics_json() const
{
json_t* rval = json_object();
json_object_set_new(rval, "monitor_id", json_integer(m_id));
json_object_set_new(rval, "detect_stale_master", json_boolean(m_detect_stale_master));
json_object_set_new(rval, "detect_stale_slave", json_boolean(m_detect_stale_slave));
json_object_set_new(rval, "detect_replication_lag", json_boolean(m_detect_replication_lag));
json_object_set_new(rval, "multimaster", json_boolean(m_detect_multimaster));
json_object_set_new(rval, "detect_standalone_master", json_boolean(m_detect_standalone_master));
json_object_set_new(rval, CN_FAILCOUNT, json_integer(m_failcount));
json_object_set_new(rval, "allow_cluster_recovery", json_boolean(m_allow_cluster_recovery));
json_object_set_new(rval, CN_AUTO_FAILOVER, json_boolean(m_auto_failover));
json_object_set_new(rval, CN_FAILOVER_TIMEOUT, json_integer(m_failover_timeout));
json_object_set_new(rval, CN_SWITCHOVER_TIMEOUT, json_integer(m_switchover_timeout));
json_object_set_new(rval, CN_AUTO_REJOIN, json_boolean(m_auto_rejoin));
json_object_set_new(rval, CN_ENFORCE_READONLY, json_boolean(m_enforce_read_only_slaves));
if (!m_script.empty())
{
json_object_set_new(rval, "script", json_string(m_script.c_str()));
}
if (m_excluded_servers.size() > 0)
{
string list = monitored_servers_to_string(m_excluded_servers);
json_object_set_new(rval, CN_NO_PROMOTE_SERVERS, json_string(list.c_str()));
}
if (!m_servers.empty())
{
json_t* arr = json_array();
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
json_array_append_new(arr, (*iter)->diagnostics_json(m_detect_multimaster));
}
json_object_set_new(rval, "server_info", arr);
}
return rval;
}
void MariaDBMonitor::update_server_status(MXS_MONITORED_SERVER* monitored_server)
{
auto i = m_server_info.find(monitored_server);
ss_dassert(i != m_server_info.end());
(*i).second->update_server(m_monitor);
}
void MariaDBMonitor::main()
{
MariaDBServer* root_master = NULL;
int log_no_master = 1;
load_journal();
if (m_detect_replication_lag)
{
check_maxscale_schema_replication();
}
/* Check monitor permissions. Failure won't cause the monitor to stop. Afterwards, close connections so
* that update_server() reconnects and checks server version. TODO: check permissions when checking
* server version. */
check_monitor_permissions(m_monitor, "SHOW SLAVE STATUS");
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
mysql_close((*iter)->m_server_base->con);
(*iter)->m_server_base->con = NULL;
}
while (!should_shutdown())
{
timespec loop_start;
/* Coarse time has resolution ~1ms (as opposed to 1ns) but this is enough. */
clock_gettime(CLOCK_MONOTONIC_COARSE, &loop_start);
lock_monitor_servers(m_monitor);
/* Read any admin status changes from SERVER->status_pending. */
if (m_monitor->server_pending_changes)
{
servers_status_pending_to_current(m_monitor);
}
/* Update MXS_MONITORED_SERVER->pending_status. This is where the monitor loop writes it's findings.
* Also, backup current status so that it can be compared to any deduced state. */
for (auto mon_srv = m_monitor->monitored_servers; mon_srv; mon_srv = mon_srv->next)
{
auto status = mon_srv->server->status;
mon_srv->pending_status = status;
mon_srv->mon_prev_status = status;
}
/* Avoid reading/writing SERVER->status while servers are not locked. Routers read the state
* all the time. */
release_monitor_servers(m_monitor);
// Query all servers for their status.
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
MariaDBServer* server = *iter;
update_server_status(server->m_server_base);
}
// Use the information to find the so far best master server.
root_master = find_root_master();
if (m_master != NULL && m_master->is_master())
{
// Update cluster-wide values dependant on the current master.
update_gtid_domain();
update_external_master();
}
// Assign relay masters, clear SERVER_SLAVE from binlog relays
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
assign_relay_master(**iter);
/* Remove SLAVE status if this server is a Binlog Server relay */
if ((*iter)->m_version == MariaDBServer::version::BINLOG_ROUTER)
{
monitor_clear_pending_status((*iter)->m_server_base, SERVER_SLAVE);
}
}
/* Update server status from monitor pending status on that server*/
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
update_server_states(**iter, root_master);
}
/** Now that all servers have their status correctly set, we can check
if we need to use standalone master. */
if (m_detect_standalone_master)
{
if (standalone_master_required())
{
// Other servers have died, set last remaining server as master
if (set_standalone_master())
{
// Update the root_master to point to the standalone master
root_master = m_master;
}
}
else
{
m_warn_set_standalone_master = true;
}
}
if (root_master && root_master->is_master())
{
// Clear slave and stale slave status bits from current master
root_master->clear_status(SERVER_SLAVE | SERVER_STALE_SLAVE);
/**
* Clear external slave status from master if configured to do so.
* This allows parts of a multi-tiered replication setup to be used
* in MaxScale.
*/
if (m_ignore_external_masters)
{
root_master->clear_status(SERVER_SLAVE_OF_EXTERNAL_MASTER);
}
}
ss_dassert(root_master == NULL || root_master == m_master);
ss_dassert(root_master == NULL ||
((root_master->m_server_base->pending_status & (SERVER_SLAVE | SERVER_MASTER)) !=
(SERVER_SLAVE | SERVER_MASTER)));
/* Generate the replication heartbeat event by performing an update */
if (m_detect_replication_lag && root_master &&
(root_master->is_master() || root_master->is_relay_server()))
{
measure_replication_lag(root_master);
}
/* Servers have been queried and states deduced. Lock servers for a short while again while we update
* the shared server states and make the changes visible. There is a problem though: the admin could
* have changed the shared state while the queries were running. In this rare case, the deduced
* server states no longer apply and may be inconsistent. The most straightforward solution to this
* is to discard the results of the latest monitor loop and start another immediately. Cluster
* modifications are not performed until the next loop. The discarding of results is not perfect as
* some data has already been written. But this data is only used by the monitor itself and will be
* rewritten next loop. TODO: make versions of log_master_changes() and mon_process_state_changes()
* which read from MXS_MONITORED_SERVER->pending_status instead of SERVER->status. Then this locking
* and releasing can be moved after failover etc and the user changes can be applied gracefully. */
lock_monitor_servers(m_monitor);
if (m_monitor->server_pending_changes)
{
MXS_WARNING("MaxAdmin or REST API modified the state of a server monitored by '%s' during a "
"monitor iteration. Discarding the monitor results and retrying.",
m_monitor->name);
release_monitor_servers(m_monitor);
}
else
{
// Update shared status.
for (auto mon_srv = m_monitor->monitored_servers; mon_srv; mon_srv = mon_srv->next)
{
auto new_status = mon_srv->pending_status;
auto srv = mon_srv->server;
srv->status = new_status;
}
/* Check if monitor events need to be launched. */
mon_process_state_changes(m_monitor, m_script.c_str(), m_events);
m_cluster_modified = false;
if (m_auto_failover)
{
m_cluster_modified = handle_auto_failover();
}
/* log master detection failure of first master becomes available after failure */
log_master_changes(root_master, &log_no_master);
// Do not auto-join servers on this monitor loop if a failover (or any other cluster modification)
// has been performed, as server states have not been updated yet. It will happen next iteration.
if (!config_get_global_options()->passive && m_auto_rejoin && !m_cluster_modified &&
cluster_can_be_joined())
{
// Check if any servers should be autojoined to the cluster and try to join them.
handle_auto_rejoin();
}
/* Check if any slave servers have read-only off and turn it on if user so wishes. Again, do not
* perform this if cluster has been modified this loop since it may not be clear which server
* should be a slave. */
if (!config_get_global_options()->passive && m_enforce_read_only_slaves && !m_cluster_modified)
{
enforce_read_only_on_slaves();
}
mon_hangup_failed_servers(m_monitor);
store_server_journal(m_monitor, m_master ? m_master->m_server_base : NULL);
release_monitor_servers(m_monitor);
}
// Check how much the monitor should sleep to get one full monitor interval.
timespec loop_end;
clock_gettime(CLOCK_MONOTONIC_COARSE, &loop_end);
int64_t time_elapsed_ms = (loop_end.tv_sec - loop_start.tv_sec) * 1000 +
(loop_end.tv_nsec - loop_start.tv_nsec) / 1000000;
int64_t sleep_time_remaining = m_monitor->interval - time_elapsed_ms;
// Sleep at least one full interval.
sleep_time_remaining = MXS_MAX(MXS_MON_BASE_INTERVAL_MS, sleep_time_remaining);
/* Sleep in small increments to react faster to some events. This should ideally use some type of
* notification mechanism. */
while (sleep_time_remaining > 0 && !should_shutdown() && !m_monitor->server_pending_changes)
{
int small_sleep_ms = (sleep_time_remaining >= MXS_MON_BASE_INTERVAL_MS) ?
MXS_MON_BASE_INTERVAL_MS : sleep_time_remaining;
thread_millisleep(small_sleep_ms);
sleep_time_remaining -= small_sleep_ms;
}
}
}
void MariaDBMonitor::update_gtid_domain()
{
int64_t domain = m_master->m_gtid_domain_id;
if (m_master_gtid_domain != GTID_DOMAIN_UNKNOWN && domain != m_master_gtid_domain)
{
MXS_NOTICE("Gtid domain id of master has changed: %" PRId64 " -> %" PRId64 ".",
m_master_gtid_domain, domain);
}
m_master_gtid_domain = domain;
}
void MariaDBMonitor::update_external_master()
{
if (SERVER_IS_SLAVE_OF_EXTERNAL_MASTER(m_master->m_server_base->server))
{
ss_dassert(!m_master->m_slave_status.empty());
if (m_master->m_slave_status[0].master_host != m_external_master_host ||
m_master->m_slave_status[0].master_port != m_external_master_port)
{
const string new_ext_host = m_master->m_slave_status[0].master_host;
const int new_ext_port = m_master->m_slave_status[0].master_port;
if (m_external_master_port == PORT_UNKNOWN)
{
MXS_NOTICE("Cluster master server is replicating from an external master: %s:%d",
new_ext_host.c_str(), new_ext_port);
}
else
{
MXS_NOTICE("The external master of the cluster has changed: %s:%d -> %s:%d.",
m_external_master_host.c_str(), m_external_master_port,
new_ext_host.c_str(), new_ext_port);
}
m_external_master_host = new_ext_host;
m_external_master_port = new_ext_port;
}
}
else
{
if (m_external_master_port != PORT_UNKNOWN)
{
MXS_NOTICE("Cluster lost the external master.");
}
m_external_master_host.clear();
m_external_master_port = PORT_UNKNOWN;
}
}
void MariaDBMonitor::measure_replication_lag(MariaDBServer* root_master)
{
ss_dassert(root_master);
MXS_MONITORED_SERVER* mon_root_master = root_master->m_server_base;
set_master_heartbeat(root_master);
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
MariaDBServer* server = *iter;
MXS_MONITORED_SERVER* ptr = server->m_server_base;
if ((!server->is_in_maintenance()) && server->is_running())
{
if (ptr->server->node_id != mon_root_master->server->node_id &&
(server->is_slave() || server->is_relay_server()) &&
(server->m_version == MariaDBServer::version::MARIADB_MYSQL_55 ||
server->m_version == MariaDBServer::version::MARIADB_100)) // No select lag for Binlog Server
{
set_slave_heartbeat(server);
}
}
}
}
void MariaDBMonitor::log_master_changes(MariaDBServer* root_master_server, int* log_no_master)
{
MXS_MONITORED_SERVER* root_master = root_master_server ? root_master_server->m_server_base : NULL;
if (root_master && mon_status_changed(root_master) &&
!(root_master->pending_status & SERVER_STALE_STATUS))
{
if ((root_master->pending_status & SERVER_MASTER) && root_master_server->is_running())
{
if (!(root_master->mon_prev_status & SERVER_STALE_STATUS) &&
!(root_master->pending_status & SERVER_MAINT))
{
MXS_NOTICE("A Master Server is now available: %s:%i",
root_master->server->address,
root_master->server->port);
}
}
else
{
MXS_ERROR("No Master can be determined. Last known was %s:%i",
root_master->server->address,
root_master->server->port);
}
*log_no_master = 1;
}
else
{
if (!root_master && *log_no_master)
{
MXS_ERROR("No Master can be determined");
*log_no_master = 0;
}
}
}
void MariaDBMonitor::handle_auto_rejoin()
{
ServerArray joinable_servers;
if (get_joinable_servers(&joinable_servers))
{
uint32_t joins = do_rejoin(joinable_servers, NULL);
if (joins > 0)
{
MXS_NOTICE("%d server(s) redirected or rejoined the cluster.", joins);
m_cluster_modified = true;
}
if (joins < joinable_servers.size())
{
MXS_ERROR("A cluster join operation failed, disabling automatic rejoining. "
"To re-enable, manually set '%s' to 'true' for monitor '%s' via MaxAdmin or "
"the REST API.", CN_AUTO_REJOIN, m_monitor->name);
m_auto_rejoin = false;
disable_setting(CN_AUTO_REJOIN);
}
}
else
{
MXS_ERROR("Query error to master '%s' prevented a possible rejoin operation.", m_master->name());
}
}
/**
* Simple wrapper for mxs_mysql_query and mysql_num_rows
*
* @param database Database connection
* @param query Query to execute
*
* @return Number of rows or -1 on error
*/
static int get_row_count(MXS_MONITORED_SERVER *database, const char* query)
{
int returned_rows = -1;
if (mxs_mysql_query(database->con, query) == 0)
{
MYSQL_RES* result = mysql_store_result(database->con);
if (result)
{
returned_rows = mysql_num_rows(result);
mysql_free_result(result);
}
}
return returned_rows;
}
/**
* Write the replication heartbeat into the maxscale_schema.replication_heartbeat table in the current master.
* The inserted value will be seen from all slaves replicating from this master.
*
* @param server The server to write the heartbeat to
*/
void MariaDBMonitor::set_master_heartbeat(MariaDBServer* server)
{
time_t heartbeat;
time_t purge_time;
char heartbeat_insert_query[512] = "";
char heartbeat_purge_query[512] = "";
if (m_master == NULL)
{
MXS_ERROR("set_master_heartbeat called without an available Master server");
return;
}
MXS_MONITORED_SERVER* database = server->m_server_base;
int n_db = get_row_count(database, "SELECT schema_name FROM information_schema.schemata "
"WHERE schema_name = 'maxscale_schema'");
int n_tbl = get_row_count(database, "SELECT table_name FROM information_schema.tables "
"WHERE table_schema = 'maxscale_schema' "
"AND table_name = 'replication_heartbeat'");
if (n_db == -1 || n_tbl == -1 ||
(n_db == 0 && mxs_mysql_query(database->con, "CREATE DATABASE maxscale_schema")) ||
(n_tbl == 0 && mxs_mysql_query(database->con, "CREATE TABLE IF NOT EXISTS "
"maxscale_schema.replication_heartbeat "
"(maxscale_id INT NOT NULL, "
"master_server_id INT NOT NULL, "
"master_timestamp INT UNSIGNED NOT NULL, "
"PRIMARY KEY ( master_server_id, maxscale_id ) )")))
{
MXS_ERROR("Error creating maxscale_schema.replication_heartbeat "
"table in Master server: %s", mysql_error(database->con));
database->server->rlag = MAX_RLAG_NOT_AVAILABLE;
return;
}
/* auto purge old values after 48 hours*/
purge_time = time(0) - (3600 * 48);
sprintf(heartbeat_purge_query,
"DELETE FROM maxscale_schema.replication_heartbeat WHERE master_timestamp < %lu", purge_time);
if (mxs_mysql_query(database->con, heartbeat_purge_query))
{
MXS_ERROR("Error deleting from maxscale_schema.replication_heartbeat "
"table: [%s], %s",
heartbeat_purge_query,
mysql_error(database->con));
}
heartbeat = time(0);
/* set node_ts for master as time(0) */
database->server->node_ts = heartbeat;
sprintf(heartbeat_insert_query,
"UPDATE maxscale_schema.replication_heartbeat "
"SET master_timestamp = %lu WHERE master_server_id = %li AND maxscale_id = %lu",
heartbeat, m_master->m_server_base->server->node_id, m_id);
/* Try to insert MaxScale timestamp into master */
if (mxs_mysql_query(database->con, heartbeat_insert_query))
{
database->server->rlag = MAX_RLAG_NOT_AVAILABLE;
MXS_ERROR("Error updating maxscale_schema.replication_heartbeat table: [%s], %s",
heartbeat_insert_query,
mysql_error(database->con));
}
else
{
if (mysql_affected_rows(database->con) == 0)
{
heartbeat = time(0);
sprintf(heartbeat_insert_query,
"REPLACE INTO maxscale_schema.replication_heartbeat "
"(master_server_id, maxscale_id, master_timestamp ) VALUES ( %li, %lu, %lu)",
m_master->m_server_base->server->node_id, m_id, heartbeat);
if (mxs_mysql_query(database->con, heartbeat_insert_query))
{
database->server->rlag = MAX_RLAG_NOT_AVAILABLE;
MXS_ERROR("Error inserting into "
"maxscale_schema.replication_heartbeat table: [%s], %s",
heartbeat_insert_query,
mysql_error(database->con));
}
else
{
/* Set replication lag to 0 for the master */
database->server->rlag = 0;
MXS_DEBUG("heartbeat table inserted data for %s:%i",
database->server->address, database->server->port);
}
}
else
{
/* Set replication lag as 0 for the master */
database->server->rlag = 0;
MXS_DEBUG("heartbeat table updated for Master %s:%i",
database->server->address, database->server->port);
}
}
}
/*
* This function gets the replication heartbeat from the maxscale_schema.replication_heartbeat table in
* the current slave and stores the timestamp and replication lag in the slave server struct.
*
* @param server The slave to measure lag at
*/
void MariaDBMonitor::set_slave_heartbeat(MariaDBServer* server)
{
time_t heartbeat;
char select_heartbeat_query[256] = "";
MYSQL_ROW row;
MYSQL_RES *result;
if (m_master == NULL)
{
MXS_ERROR("set_slave_heartbeat called without an available Master server");
return;
}
/* Get the master_timestamp value from maxscale_schema.replication_heartbeat table */
sprintf(select_heartbeat_query, "SELECT master_timestamp "
"FROM maxscale_schema.replication_heartbeat "
"WHERE maxscale_id = %lu AND master_server_id = %li",
m_id, m_master->m_server_base->server->node_id);
MXS_MONITORED_SERVER* database = server->m_server_base;
/* if there is a master then send the query to the slave with master_id */
if (m_master != NULL && (mxs_mysql_query(database->con, select_heartbeat_query) == 0
&& (result = mysql_store_result(database->con)) != NULL))
{
int rows_found = 0;
while ((row = mysql_fetch_row(result)))
{
int rlag = MAX_RLAG_NOT_AVAILABLE;
time_t slave_read;
rows_found = 1;
heartbeat = time(0);
slave_read = strtoul(row[0], NULL, 10);
if ((errno == ERANGE && (slave_read == LONG_MAX || slave_read == LONG_MIN)) ||
(errno != 0 && slave_read == 0))
{
slave_read = 0;
}
if (slave_read)
{
/* set the replication lag */
rlag = heartbeat - slave_read;
}
/* set this node_ts as master_timestamp read from replication_heartbeat table */
database->server->node_ts = slave_read;
if (rlag >= 0)
{
/* store rlag only if greater than monitor sampling interval */
database->server->rlag = ((unsigned int)rlag > (m_monitor->interval / 1000)) ? rlag : 0;
}
else
{
database->server->rlag = MAX_RLAG_NOT_AVAILABLE;
}
MXS_DEBUG("Slave %s:%i has %i seconds lag",
database->server->address,
database->server->port,
database->server->rlag);
}
if (!rows_found)
{
database->server->rlag = MAX_RLAG_NOT_AVAILABLE;
database->server->node_ts = 0;
}
mysql_free_result(result);
}
else
{
database->server->rlag = MAX_RLAG_NOT_AVAILABLE;
database->server->node_ts = 0;
if (m_master->m_server_base->server->node_id < 0)
{
MXS_ERROR("error: replication heartbeat: "
"master_server_id NOT available for %s:%i",
database->server->address,
database->server->port);
}
else
{
MXS_ERROR("error: replication heartbeat: "
"failed selecting from hearthbeat table of %s:%i : [%s], %s",
database->server->address,
database->server->port,
select_heartbeat_query,
mysql_error(database->con));
}
}
}
/**
* Set a monitor config parameter to "false". The effect persists over stopMonitor/startMonitor but not
* MaxScale restart. Only use on boolean config settings.
*
* @param setting_name Setting to disable
*/
void MariaDBMonitor::disable_setting(const char* setting)
{
MXS_CONFIG_PARAMETER p = {};
p.name = const_cast<char*>(setting);
p.value = const_cast<char*>("false");
monitor_add_parameters(m_monitor, &p);
}
/**
* Loads saved server states. Should only be called once at the beginning of the main loop after server
* creation.
*/
void MariaDBMonitor::load_journal()
{
MXS_MONITORED_SERVER* master_output = NULL;
load_server_journal(m_monitor, &master_output);
m_master = master_output ? get_server_info(master_output) : NULL;
}
/**
* Check sql text file parameters. A parameter should either be empty or a valid file which can be opened.
*
* @return True if no errors occurred when opening the files
*/
bool MariaDBMonitor::check_sql_files()
{
const char ERRMSG[] = "%s ('%s') does not exist or cannot be accessed for reading: '%s'.";
bool rval = true;
if (!m_promote_sql_file.empty() && access(m_promote_sql_file.c_str(), R_OK) != 0)
{
rval = false;
MXS_ERROR(ERRMSG, CN_PROMOTION_SQL_FILE, m_promote_sql_file.c_str(), mxs_strerror(errno));
}
if (!m_demote_sql_file.empty() && access(m_demote_sql_file.c_str(), R_OK) != 0)
{
rval = false;
MXS_ERROR(ERRMSG, CN_DEMOTION_SQL_FILE, m_demote_sql_file.c_str(), mxs_strerror(errno));
}
return rval;
}
/**
* Command handler for 'switchover'
*
* @param args The provided arguments.
* @param output Pointer where to place output object.
*
* @return True, if the command was executed, false otherwise.
*/
bool handle_manual_switchover(const MODULECMD_ARG* args, json_t** error_out)
{
ss_dassert((args->argc >= 1) && (args->argc <= 3));
ss_dassert(MODULECMD_GET_TYPE(&args->argv[0].type) == MODULECMD_ARG_MONITOR);
ss_dassert((args->argc < 2) || (MODULECMD_GET_TYPE(&args->argv[1].type) == MODULECMD_ARG_SERVER));
ss_dassert((args->argc < 3) || (MODULECMD_GET_TYPE(&args->argv[2].type) == MODULECMD_ARG_SERVER));
bool rval = false;
if (config_get_global_options()->passive)
{
const char* const MSG = "Switchover requested but not performed, as MaxScale is in passive mode.";
PRINT_MXS_JSON_ERROR(error_out, MSG);
}
else
{
MXS_MONITOR* mon = args->argv[0].value.monitor;
auto handle = static_cast<MariaDBMonitor*>(mon->instance);
SERVER* new_master = (args->argc >= 2) ? args->argv[1].value.server : NULL;
SERVER* current_master = (args->argc == 3) ? args->argv[2].value.server : NULL;
rval = handle->manual_switchover(new_master, current_master, error_out);
}
return rval;
}
/**
* Command handler for 'failover'
*
* @param args Arguments given by user
* @param output Json error output
* @return True on success
*/
bool handle_manual_failover(const MODULECMD_ARG* args, json_t** output)
{
ss_dassert(args->argc == 1);
ss_dassert(MODULECMD_GET_TYPE(&args->argv[0].type) == MODULECMD_ARG_MONITOR);
bool rv = false;
if (config_get_global_options()->passive)
{
PRINT_MXS_JSON_ERROR(output, "Failover requested but not performed, as MaxScale is in passive mode.");
}
else
{
MXS_MONITOR* mon = args->argv[0].value.monitor;
auto handle = static_cast<MariaDBMonitor*>(mon->instance);
rv = handle->manual_failover(output);
}
return rv;
}
/**
* Command handler for 'rejoin'
*
* @param args Arguments given by user
* @param output Json error output
* @return True on success
*/
bool handle_manual_rejoin(const MODULECMD_ARG* args, json_t** output)
{
ss_dassert(args->argc == 2);
ss_dassert(MODULECMD_GET_TYPE(&args->argv[0].type) == MODULECMD_ARG_MONITOR);
ss_dassert(MODULECMD_GET_TYPE(&args->argv[1].type) == MODULECMD_ARG_SERVER);
bool rv = false;
if (config_get_global_options()->passive)
{
PRINT_MXS_JSON_ERROR(output, "Rejoin requested but not performed, as MaxScale is in passive mode.");
}
else
{
MXS_MONITOR* mon = args->argv[0].value.monitor;
SERVER* server = args->argv[1].value.server;
auto handle = static_cast<MariaDBMonitor*>(mon->instance);
rv = handle->manual_rejoin(server, output);
}
return rv;
}
string monitored_servers_to_string(const ServerArray& servers)
{
string rval;
size_t array_size = servers.size();
if (array_size > 0)
{
const char* separator = "";
for (size_t i = 0; i < array_size; i++)
{
rval += separator;
rval += servers[i]->name();
separator = ",";
}
}
return rval;
}
string get_connection_errors(const ServerArray& servers)
{
// Get errors from all connections, form a string.
string rval;
string separator;
for (auto iter = servers.begin(); iter != servers.end(); iter++)
{
const char* error = mysql_error((*iter)->m_server_base->con);
ss_dassert(*error); // Every connection should have an error.
rval += separator + (*iter)->name() + ": '" + error + "'";
separator = ", ";
}
return rval;
}
/**
* The module entry point routine. This routine populates the module object structure.
*
* @return The module object
*/
extern "C" MXS_MODULE* MXS_CREATE_MODULE()
{
MXS_NOTICE("Initialise the MariaDB Monitor module.");
static const char ARG_MONITOR_DESC[] = "Monitor name (from configuration file)";
static modulecmd_arg_type_t switchover_argv[] =
{
{
MODULECMD_ARG_MONITOR | MODULECMD_ARG_NAME_MATCHES_DOMAIN,
ARG_MONITOR_DESC
},
{ MODULECMD_ARG_SERVER | MODULECMD_ARG_OPTIONAL, "New master (optional)" },
{ MODULECMD_ARG_SERVER | MODULECMD_ARG_OPTIONAL, "Current master (optional)" }
};
modulecmd_register_command(MXS_MODULE_NAME, "switchover", MODULECMD_TYPE_ACTIVE,
handle_manual_switchover, MXS_ARRAY_NELEMS(switchover_argv),
switchover_argv, "Perform master switchover");
static modulecmd_arg_type_t failover_argv[] =
{
{
MODULECMD_ARG_MONITOR | MODULECMD_ARG_NAME_MATCHES_DOMAIN,
ARG_MONITOR_DESC
},
};
modulecmd_register_command(MXS_MODULE_NAME, "failover", MODULECMD_TYPE_ACTIVE,
handle_manual_failover, MXS_ARRAY_NELEMS(failover_argv),
failover_argv, "Perform master failover");
static modulecmd_arg_type_t rejoin_argv[] =
{
{
MODULECMD_ARG_MONITOR | MODULECMD_ARG_NAME_MATCHES_DOMAIN,
ARG_MONITOR_DESC
},
{ MODULECMD_ARG_SERVER, "Joining server" }
};
modulecmd_register_command(MXS_MODULE_NAME, "rejoin", MODULECMD_TYPE_ACTIVE,
handle_manual_rejoin, MXS_ARRAY_NELEMS(rejoin_argv),
rejoin_argv, "Rejoin server to a cluster");
static MXS_MODULE info =
{
MXS_MODULE_API_MONITOR,
MXS_MODULE_GA,
MXS_MONITOR_VERSION,
"A MariaDB Master/Slave replication monitor",
"V1.5.0",
MXS_NO_MODULE_CAPABILITIES,
&maxscale::MonitorApi<MariaDBMonitor>::s_api,
NULL, /* Process init. */
NULL, /* Process finish. */
NULL, /* Thread init. */
NULL, /* Thread finish. */
{
{"detect_replication_lag", MXS_MODULE_PARAM_BOOL, "false"},
{"detect_stale_master", MXS_MODULE_PARAM_BOOL, "true"},
{"detect_stale_slave", MXS_MODULE_PARAM_BOOL, "true"},
{"mysql51_replication", MXS_MODULE_PARAM_BOOL, "false", MXS_MODULE_OPT_DEPRECATED},
{"multimaster", MXS_MODULE_PARAM_BOOL, "false"},
{"detect_standalone_master", MXS_MODULE_PARAM_BOOL, "true"},
{CN_FAILCOUNT, MXS_MODULE_PARAM_COUNT, "5"},
{"allow_cluster_recovery", MXS_MODULE_PARAM_BOOL, "true"},
{"ignore_external_masters", MXS_MODULE_PARAM_BOOL, "false"},
{
"script",
MXS_MODULE_PARAM_PATH,
NULL,
MXS_MODULE_OPT_PATH_X_OK
},
{
"events",
MXS_MODULE_PARAM_ENUM,
MXS_MONITOR_EVENT_DEFAULT_VALUE,
MXS_MODULE_OPT_NONE,
mxs_monitor_event_enum_values
},
{CN_AUTO_FAILOVER, MXS_MODULE_PARAM_BOOL, "false"},
{CN_FAILOVER_TIMEOUT, MXS_MODULE_PARAM_COUNT, "90"},
{CN_SWITCHOVER_TIMEOUT, MXS_MODULE_PARAM_COUNT, "90"},
{CN_REPLICATION_USER, MXS_MODULE_PARAM_STRING},
{CN_REPLICATION_PASSWORD, MXS_MODULE_PARAM_STRING},
{CN_VERIFY_MASTER_FAILURE, MXS_MODULE_PARAM_BOOL, "true"},
{CN_MASTER_FAILURE_TIMEOUT, MXS_MODULE_PARAM_COUNT, "10"},
{CN_AUTO_REJOIN, MXS_MODULE_PARAM_BOOL, "false"},
{CN_ENFORCE_READONLY, MXS_MODULE_PARAM_BOOL, "false"},
{CN_NO_PROMOTE_SERVERS, MXS_MODULE_PARAM_SERVERLIST},
{CN_PROMOTION_SQL_FILE, MXS_MODULE_PARAM_PATH},
{CN_DEMOTION_SQL_FILE, MXS_MODULE_PARAM_PATH},
{MXS_END_MODULE_PARAMS}
}
};
return &info;
}
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