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MXS-1905 Switchover if master is low on disk space

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Required quite a bit of refactoring.
This commit is contained in:
Esa Korhonen
2018-08-01 10:39:30 +03:00
parent 84b3e4672f
commit c0bd5ca3a1
8 changed files with 577 additions and 255 deletions
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53
server/modules/monitor/mariadbmon/mariadbmon.cc
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@ -31,9 +31,11 @@
#include "../../../core/internal/monitor.h"
using std::string;
using maxscale::string_printf;
// Config parameter names
const char * const CN_AUTO_FAILOVER = "auto_failover";
const char * const CN_SWITCHOVER_ON_LOW_DISK_SPACE = "switchover_on_low_disk_space";
const char * const CN_PROMOTION_SQL_FILE = "promotion_sql_file";
const char * const CN_DEMOTION_SQL_FILE = "demotion_sql_file";
@ -42,7 +44,6 @@ 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_ON_LOW_DISK_SPACE[] = "switchover_on_low_disk_space";
static const char CN_SWITCHOVER_TIMEOUT[] = "switchover_timeout";
static const char CN_DETECT_STANDALONE_MASTER[] = "detect_standalone_master";
static const char CN_MAINTENANCE_ON_LOW_DISK_SPACE[] = "maintenance_on_low_disk_space";
@ -63,9 +64,9 @@ MariaDBMonitor::MariaDBMonitor(MXS_MONITOR* monitor)
, m_external_master_port(PORT_UNKNOWN)
, m_cluster_topology_changed(true)
, m_cluster_modified(false)
, m_switchover_on_low_disk_space(false)
, m_log_no_master(true)
, m_warn_failover_precond(true)
, m_warn_switchover_precond(true)
, m_warn_cannot_rejoin(true)
, m_warn_current_master_invalid(true)
, m_warn_have_better_master(true)
@ -143,6 +144,23 @@ MariaDBServer* MariaDBMonitor::get_server(int64_t id)
return (found != m_servers_by_id.end()) ? (*found).second : NULL;
}
/**
* Get the equivalent MariaDBServer.
*
* @param server Which server to search for
* @return MariaDBServer if found, NULL otherwise
*/
MariaDBServer* MariaDBMonitor::get_server(SERVER* server)
{
MariaDBServer* found = NULL;
auto mon_server = mon_get_monitored_server(m_monitor, server);
if (mon_server)
{
found = get_server_info(mon_server);
}
return found;
}
bool MariaDBMonitor::set_replication_credentials(const MXS_CONFIG_PARAMETER* params)
{
bool rval = false;
@ -486,11 +504,6 @@ void MariaDBMonitor::tick()
measure_replication_lag();
}
if (m_maintenance_on_low_disk_space)
{
set_low_disk_slaves_maintenance();
}
// Update shared status. The next functions read the shared status. TODO: change the following
// functions to read "pending_status" instead.
for (auto mon_srv = m_monitor->monitored_servers; mon_srv; mon_srv = mon_srv->next)
@ -555,6 +568,19 @@ void MariaDBMonitor::process_state_changes()
{
enforce_read_only_on_slaves();
}
/* Set low disk space slaves to maintenance.
*/
if (m_maintenance_on_low_disk_space && !m_cluster_modified)
{
set_low_disk_slaves_maintenance();
}
/* Check if the master server is on low disk space and act on it. */
if (m_switchover_on_low_disk_space && !m_cluster_modified)
{
handle_low_disk_space_master();
}
}
}
@ -1037,12 +1063,13 @@ bool MariaDBMonitor::execute_manual_command(std::function<void (void)> command,
return rval;
}
bool MariaDBMonitor::run_manual_switchover(SERVER* new_master, SERVER* current_master, json_t** error_out)
bool MariaDBMonitor::run_manual_switchover(SERVER* promotion_server, SERVER* demotion_server,
json_t** error_out)
{
bool rval = false;
bool send_ok = execute_manual_command([this, &rval, new_master, current_master, error_out]()
bool send_ok = execute_manual_command([this, &rval, promotion_server, demotion_server, error_out]()
{
rval = manual_switchover(new_master, current_master, error_out);
rval = manual_switchover(promotion_server, demotion_server, error_out);
}, error_out);
return send_ok && rval;
}
@ -1092,9 +1119,9 @@ bool handle_manual_switchover(const MODULECMD_ARG* args, json_t** error_out)
{
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->run_manual_switchover(new_master, current_master, error_out);
SERVER* promotion_server = (args->argc >= 2) ? args->argv[1].value.server : NULL;
SERVER* demotion_server = (args->argc == 3) ? args->argv[2].value.server : NULL;
rval = handle->run_manual_switchover(promotion_server, demotion_server, error_out);
}
return rval;
}