2015-08-07 14:00:55 +03:00

797 lines
23 KiB
C

/*
* This file is distributed as part of the MariaDB Corporation MaxScale. It is free
* software: you can redistribute it and/or modify it under the terms of the
* GNU General Public License as published by the Free Software Foundation,
* version 2.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 51
* Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*
* Copyright MariaDB Corporation Ab 2013-2014
*/
/**
* @file mm_mon.c - A Multi-Master Multi Muster cluster monitor
*
* @verbatim
* Revision History
*
* Date Who Description
* 08/09/14 Massimiliano Pinto Initial implementation
* 08/05/15 Markus Makela Addition of launchable scripts
*
* @endverbatim
*/
#include <mmmon.h>
/** Defined in log_manager.cc */
extern int lm_enabled_logfiles_bitmask;
extern size_t log_ses_count[];
extern __thread log_info_t tls_log_info;
static void monitorMain(void *);
static char *version_str = "V1.1.1";
MODULE_INFO info = {
MODULE_API_MONITOR,
MODULE_BETA_RELEASE,
MONITOR_VERSION,
"A Multi-Master Multi Master monitor"
};
static void *startMonitor(void *,void*);
static void stopMonitor(void *);
static void diagnostics(DCB *, void *);
static void detectStaleMaster(void *, int);
static MONITOR_SERVERS *get_current_master(MONITOR *);
bool isMySQLEvent(monitor_event_t event);
static MONITOR_OBJECT MyObject = {
startMonitor,
stopMonitor,
diagnostics
};
/**
* Implementation of the mandatory version entry point
*
* @return version string of the module
*/
char *
version()
{
return version_str;
}
/**
* The module initialisation routine, called when the module
* is first loaded.
*/
void
ModuleInit()
{
LOGIF(LM, (skygw_log_write(
LOGFILE_MESSAGE,
"Initialise the Multi-Master Monitor module %s.",
version_str)));
}
/**
* The module entry point routine. It is this routine that
* must populate the structure that is referred to as the
* "module object", this is a structure with the set of
* external entry points for this module.
*
* @return The module object
*/
MONITOR_OBJECT *
GetModuleObject()
{
return &MyObject;
}
/**
* Start the instance of the monitor, returning a handle on the monitor.
*
* This function creates a thread to execute the actual monitoring.
*
* @param arg The current handle - NULL if first start
* @return A handle to use when interacting with the monitor
*/
static void *
startMonitor(void *arg,void* opt)
{
MONITOR* mon = (MONITOR*)arg;
MM_MONITOR *handle = mon->handle;
CONFIG_PARAMETER* params = (CONFIG_PARAMETER*)opt;
bool have_events = false,script_error = false;
if (handle)
{
handle->shutdown = 0;
}
else
{
if ((handle = (MM_MONITOR *)malloc(sizeof(MM_MONITOR))) == NULL)
return NULL;
handle->shutdown = 0;
handle->id = MONITOR_DEFAULT_ID;
handle->master = NULL;
handle->script = NULL;
handle->detectStaleMaster = false;
memset(handle->events,false,sizeof(handle->events));
spinlock_init(&handle->lock);
}
while(params)
{
if(!strcmp(params->name,"detect_stale_master"))
{
handle->detectStaleMaster = config_truth_value(params->value);
}
else if(!strcmp(params->name,"script"))
{
if(handle->script)
{
free(handle->script);
}
if(access(params->value,X_OK) == 0)
{
handle->script = strdup(params->value);
}
else
{
script_error = true;
if(access(params->value,F_OK) == 0)
{
skygw_log_write(LE,
"Error: The file cannot be executed: %s",
params->value);
}
else
{
skygw_log_write(LE,
"Error: The file cannot be found: %s",
params->value);
}
handle->script = NULL;
}
}
else if(!strcmp(params->name,"events"))
{
if(mon_parse_event_string((bool*)&handle->events,sizeof(handle->events),params->value) != 0)
script_error = true;
else
have_events = true;
}
params = params->next;
}
if(script_error)
{
skygw_log_write(LE,"Error: Errors were found in the script configuration parameters "
"for the monitor '%s'. The script will not be used.",mon->name);
free(handle->script);
handle->script = NULL;
}
/** If no specific events are given, enable them all */
if(!have_events)
{
memset(handle->events,true,sizeof(handle->events));
}
handle->tid = (THREAD)thread_start(monitorMain, mon);
return handle;
}
/**
* Stop a running monitor
*
* @param arg Handle on thr running monior
*/
static void
stopMonitor(void *arg)
{
MONITOR* mon = arg;
MM_MONITOR *handle = (MM_MONITOR *)mon->handle;
handle->shutdown = 1;
thread_wait((void *)handle->tid);
}
/**
* Daignostic interface
*
* @param dcb DCB to print diagnostics
* @param arg The monitor handle
*/
static void diagnostics(DCB *dcb, void *arg)
{
MONITOR* mon = (MONITOR*)arg;
MM_MONITOR *handle = (MM_MONITOR *)mon->handle;
MONITOR_SERVERS *db;
char *sep;
switch (handle->status)
{
case MONITOR_RUNNING:
dcb_printf(dcb, "\tMonitor running\n");
break;
case MONITOR_STOPPING:
dcb_printf(dcb, "\tMonitor stopping\n");
break;
case MONITOR_STOPPED:
dcb_printf(dcb, "\tMonitor stopped\n");
break;
}
dcb_printf(dcb,"\tSampling interval:\t%lu milliseconds\n", mon->interval);
dcb_printf(dcb,"\tDetect Stale Master:\t%s\n", (handle->detectStaleMaster == 1) ? "enabled" : "disabled");
dcb_printf(dcb, "\tMonitored servers: ");
db = mon->databases;
sep = "";
while (db)
{
dcb_printf(dcb,
"%s%s:%d",
sep,
db->server->name,
db->server->port);
sep = ", ";
db = db->next;
}
dcb_printf(dcb, "\n");
}
/**
* Monitor an individual server
*
* @param handle The MySQL Monitor object
* @param database The database to probe
*/
static void
monitorDatabase(MONITOR* mon, MONITOR_SERVERS *database)
{
MM_MONITOR *handle = mon->handle;
MYSQL_ROW row;
MYSQL_RES *result;
int isslave = 0;
int ismaster = 0;
char *uname = mon->user;
char *passwd = mon->password;
unsigned long int server_version = 0;
char *server_string;
if (database->server->monuser != NULL)
{
uname = database->server->monuser;
passwd = database->server->monpw;
}
if (uname == NULL)
return;
/* Don't probe servers in maintenance mode */
if (SERVER_IN_MAINT(database->server))
return;
/** Store previous status */
database->mon_prev_status = database->server->status;
if (database->con == NULL || mysql_ping(database->con) != 0)
{
char *dpwd = decryptPassword(passwd);
int read_timeout = 1;
if(database->con)
mysql_close(database->con);
database->con = mysql_init(NULL);
mysql_options(database->con, MYSQL_OPT_READ_TIMEOUT, (void *)&read_timeout);
if (mysql_real_connect(database->con,
database->server->name,
uname,
dpwd,
NULL,
database->server->port,
NULL,
0) == NULL)
{
free(dpwd);
if (mon_print_fail_status(database))
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Error : Monitor was unable to connect to "
"server %s:%d : \"%s\"",
database->server->name,
database->server->port,
mysql_error(database->con))));
}
/* The current server is not running
*
* Store server NOT running in server and monitor server pending struct
*
*/
if (mysql_errno(database->con) == ER_ACCESS_DENIED_ERROR)
{
server_set_status(database->server, SERVER_AUTH_ERROR);
monitor_set_pending_status(database, SERVER_AUTH_ERROR);
}
server_clear_status(database->server, SERVER_RUNNING);
monitor_clear_pending_status(database, SERVER_RUNNING);
/* Also clear M/S state in both server and monitor server pending struct */
server_clear_status(database->server, SERVER_SLAVE);
server_clear_status(database->server, SERVER_MASTER);
monitor_clear_pending_status(database, SERVER_SLAVE);
monitor_clear_pending_status(database, SERVER_MASTER);
/* Clean addition status too */
server_clear_status(database->server, SERVER_STALE_STATUS);
monitor_clear_pending_status(database, SERVER_STALE_STATUS);
return;
} else {
server_clear_status(database->server, SERVER_AUTH_ERROR);
monitor_clear_pending_status(database, SERVER_AUTH_ERROR);
}
free(dpwd);
}
/* Store current status in both server and monitor server pending struct */
server_set_status(database->server, SERVER_RUNNING);
monitor_set_pending_status(database, SERVER_RUNNING);
/* get server version from current server */
server_version = mysql_get_server_version(database->con);
/* get server version string */
server_string = (char *)mysql_get_server_info(database->con);
if (server_string) {
database->server->server_string = realloc(database->server->server_string, strlen(server_string)+1);
if (database->server->server_string)
strcpy(database->server->server_string, server_string);
}
/* get server_id form current node */
if (mysql_query(database->con, "SELECT @@server_id") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
long server_id = -1;
if(mysql_field_count(database->con) != 1)
{
mysql_free_result(result);
skygw_log_write(LE,"Error: Unexpected result for 'SELECT @@server_id'. Expected 1 column."
" MySQL Version: %s",version_str);
return;
}
while ((row = mysql_fetch_row(result)))
{
server_id = strtol(row[0], NULL, 10);
if ((errno == ERANGE && (server_id == LONG_MAX
|| server_id == LONG_MIN)) || (errno != 0 && server_id == 0))
{
server_id = -1;
}
database->server->node_id = server_id;
}
mysql_free_result(result);
}
/* Check if the Slave_SQL_Running and Slave_IO_Running status is
* set to Yes
*/
/* Check first for MariaDB 10.x.x and get status for multimaster replication */
if (server_version >= 100000) {
if (mysql_query(database->con, "SHOW ALL SLAVES STATUS") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
int i = 0;
long master_id = -1;
if(mysql_field_count(database->con) < 42)
{
mysql_free_result(result);
skygw_log_write(LE,"Error: \"SHOW ALL SLAVES STATUS\" "
"returned less than the expected amount of columns. Expected 42 columns"
" MySQL Version: %s",version_str);
return;
}
while ((row = mysql_fetch_row(result)))
{
/* get Slave_IO_Running and Slave_SQL_Running values*/
if (strncmp(row[12], "Yes", 3) == 0
&& strncmp(row[13], "Yes", 3) == 0) {
isslave += 1;
}
/* If Slave_IO_Running = Yes, assign the master_id to current server: this allows building
* the replication tree, slaves ids will be added to master(s) and we will have at least the
* root master server.
* Please note, there could be no slaves at all if Slave_SQL_Running == 'No'
*/
if (strncmp(row[12], "Yes", 3) == 0) {
/* get Master_Server_Id values */
master_id = atol(row[41]);
if (master_id == 0)
master_id = -1;
}
i++;
}
/* store master_id of current node */
memcpy(&database->server->master_id, &master_id, sizeof(long));
mysql_free_result(result);
/* If all configured slaves are running set this node as slave */
if (isslave > 0 && isslave == i)
isslave = 1;
else
isslave = 0;
}
} else {
if (mysql_query(database->con, "SHOW SLAVE STATUS") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
long master_id = -1;
if(mysql_field_count(database->con) < 40)
{
mysql_free_result(result);
if(server_version < 5*10000 + 5*100)
{
if(database->log_version_err)
{
skygw_log_write(LE,"Error: \"SHOW SLAVE STATUS\" "
" for versions less than 5.5 does not have master_server_id, "
"replication tree cannot be resolved for server %s."
" MySQL Version: %s",database->server->unique_name,version_str);
database->log_version_err = false;
}
}
else
{
skygw_log_write(LE,"Error: \"SHOW SLAVE STATUS\" "
"returned less than the expected amount of columns. Expected 40 columns."
" MySQL Version: %s",version_str);
}
return;
}
while ((row = mysql_fetch_row(result)))
{
/* get Slave_IO_Running and Slave_SQL_Running values*/
if (strncmp(row[10], "Yes", 3) == 0
&& strncmp(row[11], "Yes", 3) == 0) {
isslave = 1;
}
/* If Slave_IO_Running = Yes, assign the master_id to current server: this allows building
* the replication tree, slaves ids will be added to master(s) and we will have at least the
* root master server.
* Please note, there could be no slaves at all if Slave_SQL_Running == 'No'
*/
if (strncmp(row[10], "Yes", 3) == 0) {
/* get Master_Server_Id values */
master_id = atol(row[39]);
if (master_id == 0)
master_id = -1;
}
}
/* store master_id of current node */
memcpy(&database->server->master_id, &master_id, sizeof(long));
mysql_free_result(result);
}
}
/* get variable 'read_only' set by an external component */
if (mysql_query(database->con, "SHOW GLOBAL VARIABLES LIKE 'read_only'") == 0
&& (result = mysql_store_result(database->con)) != NULL)
{
if(mysql_field_count(database->con) < 2)
{
mysql_free_result(result);
skygw_log_write(LE,"Error: Unexpected result for \"SHOW GLOBAL VARIABLES LIKE 'read_only'\". Expected 2 columns."
" MySQL Version: %s",version_str);
return;
}
while ((row = mysql_fetch_row(result)))
{
if (strncasecmp(row[1], "OFF", 3) == 0) {
ismaster = 1;
} else {
isslave = 1;
}
}
mysql_free_result(result);
}
/* Remove addition info */
monitor_clear_pending_status(database, SERVER_STALE_STATUS);
/* Set the Slave Role */
if (isslave)
{
monitor_set_pending_status(database, SERVER_SLAVE);
/* Avoid any possible stale Master state */
monitor_clear_pending_status(database, SERVER_MASTER);
/* Set replication depth to 1 */
database->server->depth = 1;
} else {
/* Avoid any possible Master/Slave stale state */
monitor_clear_pending_status(database, SERVER_SLAVE);
monitor_clear_pending_status(database, SERVER_MASTER);
}
/* Set the Master role */
if (ismaster)
{
monitor_clear_pending_status(database, SERVER_SLAVE);
monitor_set_pending_status(database, SERVER_MASTER);
/* Set replication depth to 0 */
database->server->depth = 0;
}
}
/**
* The entry point for the monitoring module thread
*
* @param arg The handle of the monitor
*/
static void
monitorMain(void *arg)
{
MONITOR* mon = (MONITOR*)arg;
MM_MONITOR *handle;
MONITOR_SERVERS *ptr;
int detect_stale_master = false;
MONITOR_SERVERS *root_master = NULL;
size_t nrounds = 0;
spinlock_acquire(&mon->lock);
handle = (MM_MONITOR *)mon->handle;
spinlock_release(&mon->lock);
detect_stale_master = handle->detectStaleMaster;
if (mysql_thread_init())
{
LOGIF(LE, (skygw_log_write_flush(
LOGFILE_ERROR,
"Fatal : mysql_thread_init failed in monitor "
"module. Exiting.\n")));
return;
}
handle->status = MONITOR_RUNNING;
while (1)
{
if (handle->shutdown)
{
handle->status = MONITOR_STOPPING;
mysql_thread_end();
handle->status = MONITOR_STOPPED;
return;
}
/** Wait base interval */
thread_millisleep(MON_BASE_INTERVAL_MS);
/**
* Calculate how far away the monitor interval is from its full
* cycle and if monitor interval time further than the base
* interval, then skip monitoring checks. Excluding the first
* round.
*/
if (nrounds != 0 &&
((nrounds*MON_BASE_INTERVAL_MS)%mon->interval) >=
MON_BASE_INTERVAL_MS)
{
nrounds += 1;
continue;
}
nrounds += 1;
/* start from the first server in the list */
ptr = mon->databases;
while (ptr)
{
/* copy server status into monitor pending_status */
ptr->pending_status = ptr->server->status;
/* monitor current node */
monitorDatabase(mon, ptr);
if (mon_status_changed(ptr))
{
dcb_call_foreach(ptr->server,DCB_REASON_NOT_RESPONDING);
}
if (mon_status_changed(ptr) ||
mon_print_fail_status(ptr))
{
LOGIF(LD, (skygw_log_write_flush(
LOGFILE_DEBUG,
"Backend server %s:%d state : %s",
ptr->server->name,
ptr->server->port,
STRSRVSTATUS(ptr->server))));
}
if (SERVER_IS_DOWN(ptr->server))
{
/** Increase this server'e error count */
ptr->mon_err_count += 1;
}
else
{
/** Reset this server's error count */
ptr->mon_err_count = 0;
}
ptr = ptr->next;
}
/* Get Master server pointer */
root_master = get_current_master(mon);
/* Update server status from monitor pending status on that server*/
ptr = mon->databases;
while (ptr)
{
if (! SERVER_IN_MAINT(ptr->server)) {
/* If "detect_stale_master" option is On, let's use the previus master */
if (detect_stale_master && root_master && (!strcmp(ptr->server->name, root_master->server->name) && ptr->server->port == root_master->server->port) && (ptr->server->status & SERVER_MASTER) && !(ptr->pending_status & SERVER_MASTER)) {
/* in this case server->status will not be updated from pending_status */
LOGIF(LM, (skygw_log_write_flush(
LOGFILE_MESSAGE, "[mysql_mon]: root server [%s:%i] is no longer Master, let's use it again even if it could be a stale master, you have been warned!", ptr->server->name, ptr->server->port)));
/* Set the STALE bit for this server in server struct */
server_set_status(ptr->server, SERVER_STALE_STATUS);
} else {
ptr->server->status = ptr->pending_status;
}
}
ptr = ptr->next;
}
ptr = mon->databases;
monitor_event_t evtype;
while(ptr)
{
if(mon_status_changed(ptr))
{
evtype = mon_get_event_type(ptr);
if(isMySQLEvent(evtype))
{
skygw_log_write(LOGFILE_TRACE,"Server changed state: %s[%s:%u]: %s",
ptr->server->unique_name,
ptr->server->name,ptr->server->port,
mon_get_event_name(ptr));
if(handle->script && handle->events[evtype])
{
monitor_launch_script(mon,ptr,handle->script);
}
}
}
ptr = ptr->next;
}
}
}
/**
* Enable/Disable the MySQL Replication Stale Master dectection, allowing a previouvsly detected master to still act as a Master.
* This option must be enabled in order to keep the Master when the replication is stopped or removed from slaves.
* If the replication is still stopped when MaxSclale is restarted no Master will be available.
*
* @param arg The handle allocated by startMonitor
* @param enable To enable it 1, disable it with 0
*/
static void
detectStaleMaster(void *arg, int enable)
{
MONITOR* mon = (MONITOR*)arg;
MM_MONITOR *handle = (MM_MONITOR *)mon->handle;
memcpy(&handle->detectStaleMaster, &enable, sizeof(int));
}
/*******
* This function returns the master server
* from a set of MySQL Multi Master monitored servers
* and returns the root server (that has SERVER_MASTER bit)
* The server is returned even for servers in 'maintenance' mode.
*
* @param handle The monitor handle
* @return The server at root level with SERVER_MASTER bit
*/
static MONITOR_SERVERS *get_current_master(MONITOR *mon) {
MM_MONITOR* handle = mon->handle;
MONITOR_SERVERS *ptr;
ptr = mon->databases;
while (ptr)
{
/* The server could be in SERVER_IN_MAINT
* that means SERVER_IS_RUNNING returns 0
* Let's check only for SERVER_IS_DOWN: server is not running
*/
if (SERVER_IS_DOWN(ptr->server)) {
ptr = ptr->next;
continue;
}
if (ptr->server->depth == 0) {
handle->master = ptr;
}
ptr = ptr->next;
}
/*
* Return the root master
*/
if (handle->master != NULL) {
/* If the root master is in MAINT, return NULL */
if (SERVER_IN_MAINT(handle->master->server)) {
return NULL;
} else {
return handle->master;
}
} else {
return NULL;
}
}
static monitor_event_t mysql_events[] = {
MASTER_DOWN_EVENT,
MASTER_UP_EVENT,
SLAVE_DOWN_EVENT,
SLAVE_UP_EVENT,
SERVER_DOWN_EVENT,
SERVER_UP_EVENT,
LOST_MASTER_EVENT,
LOST_SLAVE_EVENT,
NEW_MASTER_EVENT,
NEW_SLAVE_EVENT,
MAX_MONITOR_EVENT
};
/**
* Check if the MM monitor is monitoring this event type.
* @param event Event to check
* @return True if the event is monitored, false if it is not
* */
bool isMySQLEvent(monitor_event_t event)
{
int i;
for(i = 0;mysql_events[i] != MAX_MONITOR_EVENT;i++)
{
if(event == mysql_events[i])
return true;
}
return false;
}