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MaxScale/server/modules/monitor/mariadbmon/mariadbmon.cc

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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 monitorAddParameters
#include "../../../core/internal/monitor.h"
using std::string;
static void monitorMain(void *);
// Config parameter names
const char * const CN_AUTO_FAILOVER = "auto_failover";
static const char CN_AUTO_REJOIN[] = "auto_rejoin";
static const char CN_FAILCOUNT[] = "failcount";
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";
/** Default port */
const int PORT_UNKNOWN = 0;
MariaDBMonitor::MariaDBMonitor(MXS_MONITOR* monitor_base)
: m_monitor_base(monitor_base)
, m_id(config_get_global_options()->id)
, m_master_gtid_domain(-1)
, m_external_master_port(PORT_UNKNOWN)
, m_warn_set_standalone_master(true)
{}
MariaDBMonitor::~MariaDBMonitor()
{}
/**
* Initialize the server info hashtable.
*/
void MariaDBMonitor::init_server_info()
{
// If this monitor is being restarted, the server data needs to be freed.
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
delete *iter;
}
m_servers.clear();
for (auto mon_server = m_monitor_base->monitored_servers; mon_server; mon_server = mon_server->next)
{
m_servers.push_back(new MariaDBServer(mon_server));
}
m_server_info.clear();
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
auto mon_server = (*iter)->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);
}
}
/**
* 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));
}
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_base->user;
repl_pw = m_monitor_base->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::start(MXS_MONITOR *monitor, const MXS_CONFIG_PARAMETER* params)
{
bool error = false;
MariaDBMonitor *handle = static_cast<MariaDBMonitor*>(monitor->handle);
if (handle == NULL)
{
handle = new MariaDBMonitor(monitor);
}
/* Always reset these values. The server dependent values must be reset as servers could have been
* added and removed. */
handle->m_keep_running = true;
handle->m_master = NULL;
handle->init_server_info();
if (!handle->load_config_params(params))
{
error = true;
}
if (!check_monitor_permissions(monitor, "SHOW SLAVE STATUS"))
{
error = true;
}
if (!error)
{
if (thread_start(&handle->m_thread, monitorMain, handle, 0) == NULL)
{
MXS_ERROR("Failed to start monitor thread for monitor '%s'.", monitor->name);
error = true;
}
}
if (error)
{
MXS_ERROR("Failed to start monitor. See earlier errors for more information.");
delete handle;
handle = NULL;
}
return handle;
}
/**
* Load config parameters
*
* @param params Config parameters
* @return True if settings are ok
*/
bool MariaDBMonitor::load_config_params(const MXS_CONFIG_PARAMETER* params)
{
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_mysql51_replication = config_get_bool(params, "mysql51_replication");
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_verify_master_failure = config_get_bool(params, CN_VERIFY_MASTER_FAILURE);
m_master_failure_timeout = config_get_integer(params, CN_MASTER_FAILURE_TIMEOUT);
m_excluded_servers.clear();
MXS_MONITORED_SERVER** excluded_array = NULL;
int n_excluded = mon_config_get_servers(params, CN_NO_PROMOTE_SERVERS, m_monitor_base, &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 (!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;
}
/**
* Stop the monitor.
*
* @return True, if the monitor had to be stopped. False, if the monitor already was stopped.
*/
bool MariaDBMonitor::stop()
{
// There should be no race here as long as admin operations are performed
// with the single admin lock locked.
bool actually_stopped = false;
if (m_status == MXS_MONITOR_RUNNING)
{
m_keep_running = false;
thread_wait(m_thread);
actually_stopped = true;
}
return actually_stopped;
}
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, "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 (MXS_MONITORED_SERVER *db = m_monitor_base->monitored_servers; db; db = db->next)
{
const MariaDBServer* serv_info = get_server_info(db);
dcb_printf(dcb, "Server: %s\n", db->server->unique_name);
dcb_printf(dcb, "Server ID: %" PRId64 "\n", serv_info->server_id);
dcb_printf(dcb, "Read only: %s\n", serv_info->read_only ? "YES" : "NO");
dcb_printf(dcb, "Slave configured: %s\n", serv_info->slave_configured ? "YES" : "NO");
if (serv_info->slave_configured)
{
dcb_printf(dcb, "Slave IO running: %s\n",
serv_info->slave_status.slave_io_running ? "YES" : "NO");
dcb_printf(dcb, "Slave SQL running: %s\n",
serv_info->slave_status.slave_sql_running ? "YES" : "NO");
dcb_printf(dcb, "Master ID: %" PRId64 "\n",
serv_info->slave_status.master_server_id);
dcb_printf(dcb, "Master binlog file: %s\n",
serv_info->slave_status.master_log_file.c_str());
dcb_printf(dcb, "Master binlog position: %lu\n",
serv_info->slave_status.read_master_log_pos);
}
if (!serv_info->gtid_current_pos.empty())
{
dcb_printf(dcb, "Gtid current position: %s\n",
serv_info->gtid_current_pos.to_string().c_str());
}
if (!serv_info->gtid_binlog_pos.empty())
{
dcb_printf(dcb, "Gtid binlog position: %s\n",
serv_info->gtid_current_pos.to_string().c_str());
}
if (!serv_info->slave_status.gtid_io_pos.empty())
{
dcb_printf(dcb, "Gtid slave IO position: %s\n",
serv_info->slave_status.gtid_io_pos.to_string().c_str());
}
if (m_detect_multimaster)
{
dcb_printf(dcb, "Master group: %d\n", serv_info->group);
}
dcb_printf(dcb, "\n");
}
}
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, "mysql51_replication", json_boolean(m_mysql51_replication));
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));
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_monitor_base->monitored_servers)
{
json_t* arr = json_array();
for (MXS_MONITORED_SERVER *db = m_monitor_base->monitored_servers; db; db = db->next)
{
json_t* srv = json_object();
const MariaDBServer* serv_info = get_server_info(db);
json_object_set_new(srv, "name", json_string(db->server->unique_name));
json_object_set_new(srv, "server_id", json_integer(serv_info->server_id));
json_object_set_new(srv, "master_id", json_integer(serv_info->slave_status.master_server_id));
json_object_set_new(srv, "read_only", json_boolean(serv_info->read_only));
json_object_set_new(srv, "slave_configured", json_boolean(serv_info->slave_configured));
json_object_set_new(srv, "slave_io_running",
json_boolean(serv_info->slave_status.slave_io_running));
json_object_set_new(srv, "slave_sql_running",
json_boolean(serv_info->slave_status.slave_sql_running));
json_object_set_new(srv, "master_binlog_file",
json_string(serv_info->slave_status.master_log_file.c_str()));
json_object_set_new(srv, "master_binlog_position",
json_integer(serv_info->slave_status.read_master_log_pos));
json_object_set_new(srv, "gtid_current_pos",
json_string(serv_info->gtid_current_pos.to_string().c_str()));
json_object_set_new(srv, "gtid_binlog_pos",
json_string(serv_info->gtid_binlog_pos.to_string().c_str()));
json_object_set_new(srv, "gtid_io_pos",
json_string(serv_info->slave_status.gtid_io_pos.to_string().c_str()));
if (m_detect_multimaster)
{
json_object_set_new(srv, "master_group", json_integer(serv_info->group));
}
json_array_append_new(arr, srv);
}
json_object_set_new(rval, "server_info", arr);
}
return rval;
}
void MariaDBMonitor::main_loop()
{
m_status = MXS_MONITOR_RUNNING;
MariaDBServer* root_master = NULL;
int log_no_master = 1;
if (mysql_thread_init())
{
MXS_ERROR("mysql_thread_init failed in monitor module. Exiting.");
m_status = MXS_MONITOR_STOPPED;
return;
}
load_journal();
if (m_detect_replication_lag)
{
check_maxscale_schema_replication();
}
while (m_keep_running)
{
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_base);
servers_status_pending_to_current(m_monitor_base);
// Query all servers for their status.
for (auto iter = m_servers.begin(); iter != m_servers.end(); iter++)
{
monitor_one_server(**iter);
}
// 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)->binlog_relay)
{
monitor_clear_pending_status((*iter)->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())
{
SERVER* root_master_server = root_master->server_base->server;
// Clear slave and stale slave status bits from current master
server_clear_status_nolock(root_master_server, SERVER_SLAVE | SERVER_STALE_SLAVE);
monitor_clear_pending_status(root_master->server_base, 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)
{
monitor_clear_pending_status(root_master->server_base, SERVER_SLAVE_OF_EXTERNAL_MASTER);
server_clear_status_nolock(root_master_server, SERVER_SLAVE_OF_EXTERNAL_MASTER);
}
}
ss_dassert(root_master == NULL || root_master == m_master);
ss_dassert(root_master == NULL ||
((root_master->server_base->server->status & (SERVER_SLAVE | SERVER_MASTER)) !=
(SERVER_SLAVE | SERVER_MASTER)));
/**
* After updating the status of all servers, check if monitor events
* need to be launched.
*/
mon_process_state_changes(m_monitor_base, m_script.c_str(), m_events);
bool failover_performed = false; // Has an automatic failover been performed this loop?
if (m_auto_failover)
{
handle_auto_failover(&failover_performed);
}
/* log master detection failure of first master becomes available after failure */
log_master_changes(root_master, &log_no_master);
/* Generate the replication heartbeat event by performing an update */
if (m_detect_replication_lag && root_master &&
(root_master->is_master() || SERVER_IS_RELAY_SERVER(root_master->server_base->server)))
{
measure_replication_lag(root_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 &&
!failover_performed && cluster_can_be_joined())
{
// Check if any servers should be autojoined to the cluster and try to join them.
handle_auto_rejoin();
}
mon_hangup_failed_servers(m_monitor_base);
servers_status_current_to_pending(m_monitor_base);
store_server_journal(m_monitor_base, m_master ? m_master->server_base : NULL);
release_monitor_servers(m_monitor_base);
// 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;
/* Sleep in small increments to react faster to some events. This should ideally use some type of
* notification mechanism. */
int sleep_cycles = ((m_monitor_base->interval - time_elapsed_ms) / MXS_MON_BASE_INTERVAL_MS);
sleep_cycles = MXS_MAX(1, sleep_cycles); // Sleep at least once.
for (int i = 0; i < sleep_cycles; i++)
{
thread_millisleep(MXS_MON_BASE_INTERVAL_MS);
if (!m_keep_running || m_monitor_base->server_pending_changes)
{
break;
}
}
}
m_status = MXS_MONITOR_STOPPING;
mysql_thread_end();
m_status = MXS_MONITOR_STOPPED;
}
void MariaDBMonitor::update_gtid_domain()
{
int64_t domain = m_master->gtid_domain_id;
if (m_master_gtid_domain >= 0 && 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->server_base->server))
{
if (m_master->slave_status.master_host != m_external_master_host ||
m_master->slave_status.master_port != m_external_master_port)
{
const string new_ext_host = m_master->slave_status.master_host;
const int new_ext_port = m_master->slave_status.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->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->server_base;
if ((!SERVER_IN_MAINT(ptr->server)) && server->is_running())
{
if (ptr->server->node_id != mon_root_master->server->node_id &&
(server->is_slave() || SERVER_IS_RELAY_SERVER(ptr->server)) &&
!server->binlog_relay) // No select lag for Binlog Server
{
set_slave_heartbeat(server);
}
}
}
}
void MariaDBMonitor::handle_auto_failover(bool* failover_performed)
{
const char RE_ENABLE_FMT[] = "%s To re-enable failover, manually set '%s' to 'true' for monitor "
"'%s' via MaxAdmin or the REST API, or restart MaxScale.";
if (failover_not_possible())
{
const char PROBLEMS[] = "Failover is not possible due to one or more problems in the "
"replication configuration, disabling automatic failover. Failover "
"should only be enabled after the replication configuration has been "
"fixed.";
MXS_ERROR(RE_ENABLE_FMT, PROBLEMS, CN_AUTO_FAILOVER, m_monitor_base->name);
m_auto_failover = false;
disable_setting(CN_AUTO_FAILOVER);
}
// If master seems to be down, check if slaves are receiving events.
else if (m_verify_master_failure && m_master && m_master->is_down() && slave_receiving_events())
{
MXS_INFO("Master failure not yet confirmed by slaves, delaying failover.");
}
else if (!mon_process_failover(failover_performed))
{
const char FAILED[] = "Failed to perform failover, disabling automatic failover.";
MXS_ERROR(RE_ENABLE_FMT, FAILED, CN_AUTO_FAILOVER, m_monitor_base->name);
m_auto_failover = false;
disable_setting(CN_AUTO_FAILOVER);
}
}
void MariaDBMonitor::log_master_changes(MariaDBServer* root_master_server, int* log_no_master)
{
MXS_MONITORED_SERVER* root_master = root_master_server ? root_master_server->server_base : NULL;
if (root_master &&
mon_status_changed(root_master) &&
!(root_master->server->status & SERVER_STALE_STATUS))
{
if (root_master->pending_status & (SERVER_MASTER) && SERVER_IS_RUNNING(root_master->server))
{
if (!(root_master->mon_prev_status & SERVER_STALE_STATUS) &&
!(root_master->server->status & SERVER_MAINT))
{
MXS_NOTICE("A Master Server is now available: %s:%i",
root_master->server->name,
root_master->server->port);
}
}
else
{
MXS_ERROR("No Master can be determined. Last known was %s:%i",
root_master->server->name,
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);
if (joins > 0)
{
MXS_NOTICE("%d server(s) redirected or rejoined the cluster.", joins);
}
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_base->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());
}
}
/**
* The entry point for the monitoring module thread
*
* @param arg The handle of the monitor. Must be the object returned by startMonitor.
*/
static void monitorMain(void *arg)
{
MariaDBMonitor* handle = static_cast<MariaDBMonitor*>(arg);
handle->main_loop();
}
/**
* 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->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->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->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->name, 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->name, 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->server_base->server->node_id);
MXS_MONITORED_SERVER* database = server->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_base->interval / 1000)) ? rlag : 0;
}
else
{
database->server->rlag = MAX_RLAG_NOT_AVAILABLE;
}
MXS_DEBUG("Slave %s:%i has %i seconds lag",
database->server->name,
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->server_base->server->node_id < 0)
{
MXS_ERROR("error: replication heartbeat: "
"master_server_id NOT available for %s:%i",
database->server->name,
database->server->port);
}
else
{
MXS_ERROR("error: replication heartbeat: "
"failed selecting from hearthbeat table of %s:%i : [%s], %s",
database->server->name,
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");
monitorAddParameters(m_monitor_base, &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_base, &master_output);
m_master = master_output ? get_server_info(master_output) : NULL;
}
/**
* Start the monitor instance and return the instance data. This function creates a thread to
* execute the monitoring. Use stopMonitor() to stop the thread.
*
* @param monitor General monitor data
* @param params Configuration parameters
* @return A pointer to MariaDBMonitor specific data. Should be stored in MXS_MONITOR's "handle"-field.
*/
static void* startMonitor(MXS_MONITOR *monitor, const MXS_CONFIG_PARAMETER* params)
{
return MariaDBMonitor::start(monitor, params);
}
/**
* Stop a running monitor
*
* @param mon The monitor that should be stopped.
*/
static void stopMonitor(MXS_MONITOR *mon)
{
auto handle = static_cast<MariaDBMonitor*>(mon->handle);
handle->stop();
}
/**
* Daignostic interface
*
* @param dcb DCB to print diagnostics
* @param arg The monitor handle
*/
static void diagnostics(DCB *dcb, const MXS_MONITOR *mon)
{
const MariaDBMonitor* handle = static_cast<const MariaDBMonitor*>(mon->handle);
handle->diagnostics(dcb);
}
/**
* Diagnostic interface
*
* @param arg The monitor handle
*/
static json_t* diagnostics_json(const MXS_MONITOR *mon)
{
const MariaDBMonitor *handle = (const MariaDBMonitor *)mon->handle;
return handle->diagnostics_json();
}
/**
* 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 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->handle);
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->handle);
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->handle);
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)->server_base->con);
ss_dassert(*error); // Every connection should have an error.
rval += separator + (*iter)->name() + ": '" + error + "'";
separator = ", ";
}
return rval;
}
MXS_BEGIN_DECLS
/**
* The module entry point routine. This routine populates the module object structure.
*
* @return The module object
*/
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_MONITOR_OBJECT MyObject =
{
startMonitor,
stopMonitor,
diagnostics,
diagnostics_json
};
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,
&MyObject,
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"},
{"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_NO_PROMOTE_SERVERS, MXS_MODULE_PARAM_SERVERLIST},
{MXS_END_MODULE_PARAMS}
}
};
return &info;
}
MXS_END_DECLS
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