MariaDBMon: Move replication manipulation functions to a separate file
Refactoring continues. This update moves some of the replication manipulation functions to a separate file and turns them into class methods.
This commit is contained in:
Esa Korhonen
191
server/modules/monitor/mariadbmon/cluster_manipulation.cc
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191
server/modules/monitor/mariadbmon/cluster_manipulation.cc
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#include "mariadbmon.hh"
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#include <sstream>
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#include <maxscale/mysql_utils.h>
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/*
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* Copyright (c) 2018 MariaDB Corporation Ab
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*
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* Use of this software is governed by the Business Source License included
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* in the LICENSE.TXT file and at www.mariadb.com/bsl11.
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*
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* Change Date: 2020-01-01
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*
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* On the date above, in accordance with the Business Source License, use
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* of this software will be governed by version 2 or later of the General
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* Public License.
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*/
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/**
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* Generate a CHANGE MASTER TO-query.
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*
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* @param master_host Master hostname/address
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* @param master_port Master port
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* @return Generated query
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*/
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string MariaDBMonitor::generate_change_master_cmd(const string& master_host, int master_port)
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{
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std::stringstream change_cmd;
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change_cmd << "CHANGE MASTER TO MASTER_HOST = '" << master_host << "', ";
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change_cmd << "MASTER_PORT = " << master_port << ", ";
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change_cmd << "MASTER_USE_GTID = current_pos, ";
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change_cmd << "MASTER_USER = '" << m_replication_user << "', ";
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const char MASTER_PW[] = "MASTER_PASSWORD = '";
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const char END[] = "';";
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#if defined(SS_DEBUG)
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std::stringstream change_cmd_nopw;
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change_cmd_nopw << change_cmd.str();
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change_cmd_nopw << MASTER_PW << "******" << END;;
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MXS_DEBUG("Change master command is '%s'.", change_cmd_nopw.str().c_str());
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#endif
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change_cmd << MASTER_PW << m_replication_password << END;
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return change_cmd.str();
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}
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/**
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* Redirects slaves to replicate from another master server.
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*
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* @param slaves An array of slaves
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* @param new_master The replication master
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* @param redirected_slaves A vector where to insert successfully redirected slaves.
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* @return The number of slaves successfully redirected.
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*/
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int MariaDBMonitor::redirect_slaves(MXS_MONITORED_SERVER* new_master, const ServerVector& slaves,
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ServerVector* redirected_slaves)
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{
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ss_dassert(redirected_slaves != NULL);
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MXS_NOTICE("Redirecting slaves to new master.");
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string change_cmd = generate_change_master_cmd(new_master->server->name, new_master->server->port);
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int successes = 0;
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for (ServerVector::const_iterator iter = slaves.begin(); iter != slaves.end(); iter++)
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{
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if (redirect_one_slave(*iter, change_cmd.c_str()))
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{
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successes++;
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redirected_slaves->push_back(*iter);
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}
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}
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return successes;
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}
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/**
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* Set the new master to replicate from the cluster external master.
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*
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* @param new_master The server being promoted
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* @param err_out Error output
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* @return True if new master accepted commands
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*/
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bool MariaDBMonitor::start_external_replication(MXS_MONITORED_SERVER* new_master, json_t** err_out)
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{
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bool rval = false;
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string change_cmd = generate_change_master_cmd(external_master_host, external_master_port);
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if (mxs_mysql_query(new_master->con, change_cmd.c_str()) == 0 &&
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mxs_mysql_query(new_master->con, "START SLAVE;") == 0)
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{
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MXS_NOTICE("New master starting replication from external master %s:%d.",
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external_master_host.c_str(), external_master_port);
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rval = true;
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}
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else
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{
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PRINT_MXS_JSON_ERROR(err_out, "Could not start replication from external master: '%s'.",
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mysql_error(new_master->con));
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}
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return rval;
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}
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/**
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* Starts a new slave connection on a server. Should be used on a demoted master server.
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*
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* @param old_master The server which will start replication
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* @param new_master Replication target
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* @return True if commands were accepted. This does not guarantee that replication proceeds
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* successfully.
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*/
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bool MariaDBMonitor::switchover_start_slave(MXS_MONITORED_SERVER* old_master, SERVER* new_master)
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{
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bool rval = false;
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string change_cmd = generate_change_master_cmd(new_master->name, new_master->port);
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if (mxs_mysql_query(old_master->con, change_cmd.c_str()) == 0 &&
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mxs_mysql_query(old_master->con, "START SLAVE;") == 0)
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{
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MXS_NOTICE("Old master '%s' starting replication from '%s'.",
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old_master->server->unique_name, new_master->unique_name);
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rval = true;
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}
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else
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{
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MXS_ERROR("Old master '%s' could not start replication: '%s'.",
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old_master->server->unique_name, mysql_error(old_master->con));
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}
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return rval;
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}
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/**
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* Redirect one slave server to another master
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*
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* @param slave Server to redirect
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* @param change_cmd Change master command, usually generated by generate_change_master_cmd()
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* @return True if slave accepted all commands
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*/
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bool MariaDBMonitor::redirect_one_slave(MXS_MONITORED_SERVER* slave, const char* change_cmd)
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{
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bool rval = false;
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if (mxs_mysql_query(slave->con, "STOP SLAVE;") == 0 &&
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mxs_mysql_query(slave->con, "RESET SLAVE;") == 0 && // To erase any old I/O or SQL errors
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mxs_mysql_query(slave->con, change_cmd) == 0 &&
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mxs_mysql_query(slave->con, "START SLAVE;") == 0)
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{
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rval = true;
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MXS_NOTICE("Slave '%s' redirected to new master.", slave->server->unique_name);
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}
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else
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{
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MXS_WARNING("Slave '%s' redirection failed: '%s'.", slave->server->unique_name,
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mysql_error(slave->con));
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}
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return rval;
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}
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uint32_t MariaDBMonitor::do_rejoin(const ServerVector& joinable_servers)
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{
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SERVER* master = this->master->server;
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uint32_t servers_joined = 0;
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if (!joinable_servers.empty())
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{
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string change_cmd = generate_change_master_cmd(master->name, master->port);
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for (ServerVector::const_iterator iter = joinable_servers.begin();
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iter != joinable_servers.end();
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iter++)
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{
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MXS_MONITORED_SERVER* joinable = *iter;
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const char* name = joinable->server->unique_name;
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const char* master_name = master->unique_name;
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MySqlServerInfo* redir_info = get_server_info(this, joinable);
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bool op_success;
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if (redir_info->n_slaves_configured == 0)
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{
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MXS_NOTICE("Directing standalone server '%s' to replicate from '%s'.", name, master_name);
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op_success = join_cluster(joinable, change_cmd.c_str());
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}
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else
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{
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MXS_NOTICE("Server '%s' is replicating from a server other than '%s', "
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"redirecting it to '%s'.", name, master_name, master_name);
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op_success = redirect_one_slave(joinable, change_cmd.c_str());
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}
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if (op_success)
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{
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servers_joined++;
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}
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}
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}
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return servers_joined;
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}
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bool MariaDBMonitor::cluster_can_be_joined()
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{
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return (master != NULL && SERVER_IS_MASTER(master->server) && master_gtid_domain >= 0);
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}
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