server/ctdb_monitor.c

   1 /*
   2    monitoring links to all other nodes to detect dead nodes
   3
   4
   5    Copyright (C) Ronnie Sahlberg 2007
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, see <http://www.gnu.org/licenses/>.
  19 */
  20
  21 #include "includes.h"
  22 #include "lib/tevent/tevent.h"
  23 #include "system/filesys.h"
  24 #include "system/wait.h"
  25 #include "../include/ctdb_private.h"
  26
  27 struct ctdb_monitor_state {
  28         uint32_t monitoring_mode;
  29         TALLOC_CTX *monitor_context;
  30         uint32_t next_interval;
  31 };
  32
  33 static void ctdb_check_health(struct event_context *ev, struct timed_event *te,
  34                               struct timeval t, void *private_data);
  35
  36 /*
  37   setup the notification script
  38 */
  39 int ctdb_set_notification_script(struct ctdb_context *ctdb, const char *script)
  40 {
  41         ctdb->notification_script = talloc_strdup(ctdb, script);
  42         CTDB_NO_MEMORY(ctdb, ctdb->notification_script);
  43         return 0;
  44 }
  45
  46 static int ctdb_run_notification_script_child(struct ctdb_context *ctdb, const char *event)
  47 {
  48         struct stat st;
  49         int ret;
  50         char *cmd;
  51
  52         if (stat(ctdb->notification_script, &st) != 0) {
  53                 DEBUG(DEBUG_ERR,("Could not stat notification script %s. Can not send notifications.\n", ctdb->notification_script));
  54                 return -1;
  55         }
  56         if (!(st.st_mode & S_IXUSR)) {
  57                 DEBUG(DEBUG_ERR,("Notification script %s is not executable.\n", ctdb->notification_script));
  58                 return -1;
  59         }
  60
  61         cmd = talloc_asprintf(ctdb, "%s %s\n", ctdb->notification_script, event);
  62         CTDB_NO_MEMORY(ctdb, cmd);
  63
  64         ret = system(cmd);
  65         /* if the system() call was successful, translate ret into the
  66            return code from the command
  67         */
  68         if (ret != -1) {
  69                 ret = WEXITSTATUS(ret);
  70         }
  71         if (ret != 0) {
  72                 DEBUG(DEBUG_ERR,("Notification script \"%s\" failed with error %d\n", cmd, ret));
  73         }
  74
  75         return ret;
  76 }
  77
  78 void ctdb_run_notification_script(struct ctdb_context *ctdb, const char *event)
  79 {
  80         pid_t child;
  81
  82         if (ctdb->notification_script == NULL) {
  83                 return;
  84         }
  85
  86         child = ctdb_fork(ctdb);
  87         if (child == (pid_t)-1) {
  88                 DEBUG(DEBUG_ERR,("Failed to fork() a notification child process\n"));
  89                 return;
  90         }
  91         if (child == 0) {
  92                 int ret;
  93
  94                 debug_extra = talloc_asprintf(NULL, "notification-%s:", event);
  95                 ret = ctdb_run_notification_script_child(ctdb, event);
  96                 if (ret != 0) {
  97                         DEBUG(DEBUG_ERR,(__location__ " Notification script failed\n"));
  98                 }
  99                 _exit(0);
 100         }
 101
 102         return;
 103 }
 104
 105 /*
 106   called when a health monitoring event script finishes
 107  */
 108 static void ctdb_health_callback(struct ctdb_context *ctdb, int status, void *p)
 109 {
 110         struct ctdb_node *node = ctdb->nodes[ctdb->pnn];
 111         TDB_DATA data;
 112         struct ctdb_node_flag_change c;
 113         uint32_t next_interval;
 114         int ret;
 115         TDB_DATA rddata;
 116         struct takeover_run_reply rd;
 117
 118         c.pnn = ctdb->pnn;
 119         c.old_flags = node->flags;
 120
 121         rd.pnn   = ctdb->pnn;
 122         rd.srvid = CTDB_SRVID_TAKEOVER_RUN_RESPONSE;
 123
 124         rddata.dptr = (uint8_t *)&rd;
 125         rddata.dsize = sizeof(rd);
 126
 127         if (status == -ECANCELED) {
 128                 DEBUG(DEBUG_ERR,("Monitoring event was cancelled\n"));
 129                 goto after_change_status;
 130         }
 131
 132         if (status == -ETIME) {
 133                 ctdb->event_script_timeouts++;
 134
 135                 if (ctdb->event_script_timeouts >= ctdb->tunable.script_timeout_count) {
 136                         DEBUG(DEBUG_ERR, ("Maximum timeout count %u reached for eventscript. Making node unhealthy\n", ctdb->tunable.script_timeout_count));
 137                 } else {
 138                         /* We pretend this is OK. */
 139                         goto after_change_status;
 140                 }
 141         }
 142
 143         if (status != 0 && !(node->flags & NODE_FLAGS_UNHEALTHY)) {
 144                 DEBUG(DEBUG_NOTICE,("monitor event failed - disabling node\n"));
 145                 node->flags |= NODE_FLAGS_UNHEALTHY;
 146                 ctdb->monitor->next_interval = 5;
 147
 148                 ctdb_run_notification_script(ctdb, "unhealthy");
 149
 150                 /* ask the recmaster to reallocate all addresses */
 151                 DEBUG(DEBUG_ERR,("Node became UNHEALTHY. Ask recovery master %u to perform ip reallocation\n", ctdb->recovery_master));
 152                 ret = ctdb_daemon_send_message(ctdb, ctdb->recovery_master, CTDB_SRVID_TAKEOVER_RUN, rddata);
 153                 if (ret != 0) {
 154                         DEBUG(DEBUG_ERR,(__location__ " Failed to send ip takeover run request message to %u\n", ctdb->recovery_master));
 155                 }
 156
 157         } else if (status == 0 && (node->flags & NODE_FLAGS_UNHEALTHY)) {
 158                 DEBUG(DEBUG_NOTICE,("monitor event OK - node re-enabled\n"));
 159                 node->flags &= ~NODE_FLAGS_UNHEALTHY;
 160                 ctdb->monitor->next_interval = 5;
 161
 162                 ctdb_run_notification_script(ctdb, "healthy");
 163
 164                 /* ask the recmaster to reallocate all addresses */
 165                 DEBUG(DEBUG_ERR,("Node became HEALTHY. Ask recovery master %u to perform ip reallocation\n", ctdb->recovery_master));
 166                 ret = ctdb_daemon_send_message(ctdb, ctdb->recovery_master, CTDB_SRVID_TAKEOVER_RUN, rddata);
 167                 if (ret != 0) {
 168                         DEBUG(DEBUG_ERR,(__location__ " Failed to send ip takeover run request message to %u\n", ctdb->recovery_master));
 169                 }
 170
 171         }
 172
 173 after_change_status:
 174         next_interval = ctdb->monitor->next_interval;
 175
 176         ctdb->monitor->next_interval *= 2;
 177         if (ctdb->monitor->next_interval > ctdb->tunable.monitor_interval) {
 178                 ctdb->monitor->next_interval = ctdb->tunable.monitor_interval;
 179         }
 180
 181         event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 182                                 timeval_current_ofs(next_interval, 0),
 183                                 ctdb_check_health, ctdb);
 184
 185         if (c.old_flags == node->flags) {
 186                 return;
 187         }
 188
 189         c.new_flags = node->flags;
 190
 191         data.dptr = (uint8_t *)&c;
 192         data.dsize = sizeof(c);
 193
 194         /* ask the recovery daemon to push these changes out to all nodes */
 195         ctdb_daemon_send_message(ctdb, ctdb->pnn,
 196                                  CTDB_SRVID_PUSH_NODE_FLAGS, data);
 197
 198 }
 199
 200
 201 /*
 202   called when the startup event script finishes
 203  */
 204 static void ctdb_startup_callback(struct ctdb_context *ctdb, int status, void *p)
 205 {
 206         if (status != 0) {
 207                 DEBUG(DEBUG_ERR,("startup event failed\n"));
 208         } else if (status == 0) {
 209                 DEBUG(DEBUG_NOTICE,("startup event OK - enabling monitoring\n"));
 210                 ctdb->done_startup = true;
 211                 ctdbd_pid = ctdb->ctdbd_pid;
 212                 ctdb->monitor->next_interval = 2;
 213                 ctdb_run_notification_script(ctdb, "startup");
 214         }
 215
 216         event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 217                         timeval_current_ofs(ctdb->monitor->next_interval, 0),
 218                         ctdb_check_health, ctdb);
 219 }
 220
 221
 222 /*
 223   wait until we have finished initial recoveries before we start the
 224   monitoring events
 225  */
 226 static void ctdb_wait_until_recovered(struct event_context *ev, struct timed_event *te,
 227                               struct timeval t, void *private_data)
 228 {
 229         struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
 230         int ret;
 231         static int count = 0;
 232
 233         count++;
 234
 235         if (count < 60 || count%600 == 0) {
 236                 DEBUG(DEBUG_NOTICE,("CTDB_WAIT_UNTIL_RECOVERED\n"));
 237                 if (ctdb->nodes[ctdb->pnn]->flags & NODE_FLAGS_STOPPED) {
 238                         DEBUG(DEBUG_NOTICE,("Node is STOPPED. Node will NOT recover.\n"));
 239                 }
 240         }
 241
 242         if (ctdb->vnn_map->generation == INVALID_GENERATION) {
 243                 ctdb->db_persistent_startup_generation = INVALID_GENERATION;
 244
 245                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 246                                      timeval_current_ofs(1, 0),
 247                                      ctdb_wait_until_recovered, ctdb);
 248                 return;
 249         }
 250
 251         if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL) {
 252                 ctdb->db_persistent_startup_generation = INVALID_GENERATION;
 253
 254                 DEBUG(DEBUG_NOTICE,(__location__ " in recovery. Wait one more second\n"));
 255                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 256                                      timeval_current_ofs(1, 0),
 257                                      ctdb_wait_until_recovered, ctdb);
 258                 return;
 259         }
 260
 261
 262         if (!fast_start && timeval_elapsed(&ctdb->last_recovery_finished) < (ctdb->tunable.rerecovery_timeout + 3)) {
 263                 ctdb->db_persistent_startup_generation = INVALID_GENERATION;
 264
 265                 DEBUG(DEBUG_NOTICE,(__location__ " wait for pending recoveries to end. Wait one more second.\n"));
 266
 267                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 268                                      timeval_current_ofs(1, 0),
 269                                      ctdb_wait_until_recovered, ctdb);
 270                 return;
 271         }
 272
 273         if (ctdb->vnn_map->generation == ctdb->db_persistent_startup_generation) {
 274                 DEBUG(DEBUG_INFO,(__location__ " skip ctdb_recheck_persistent_health() "
 275                                   "until the next recovery\n"));
 276                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 277                                      timeval_current_ofs(1, 0),
 278                                      ctdb_wait_until_recovered, ctdb);
 279                 return;
 280         }
 281
 282         ctdb->db_persistent_startup_generation = ctdb->vnn_map->generation;
 283         ret = ctdb_recheck_persistent_health(ctdb);
 284         if (ret != 0) {
 285                 ctdb->db_persistent_check_errors++;
 286                 if (ctdb->db_persistent_check_errors < ctdb->max_persistent_check_errors) {
 287                         DEBUG(ctdb->db_persistent_check_errors==1?DEBUG_ERR:DEBUG_WARNING,
 288                               (__location__ "ctdb_recheck_persistent_health() "
 289                               "failed (%llu of %llu times) - retry later\n",
 290                               (unsigned long long)ctdb->db_persistent_check_errors,
 291                               (unsigned long long)ctdb->max_persistent_check_errors));
 292                         event_add_timed(ctdb->ev,
 293                                         ctdb->monitor->monitor_context,
 294                                         timeval_current_ofs(1, 0),
 295                                         ctdb_wait_until_recovered, ctdb);
 296                         return;
 297                 }
 298                 DEBUG(DEBUG_ALERT,(__location__
 299                                   "ctdb_recheck_persistent_health() failed (%llu times) - prepare shutdown\n",
 300                                   (unsigned long long)ctdb->db_persistent_check_errors));
 301                 ctdb_stop_recoverd(ctdb);
 302                 ctdb_stop_keepalive(ctdb);
 303                 ctdb_stop_monitoring(ctdb);
 304                 ctdb_release_all_ips(ctdb);
 305                 if (ctdb->methods != NULL) {
 306                         ctdb->methods->shutdown(ctdb);
 307                 }
 308                 ctdb_event_script(ctdb, CTDB_EVENT_SHUTDOWN);
 309                 DEBUG(DEBUG_ALERT,("ctdb_recheck_persistent_health() failed - Stopping CTDB daemon\n"));
 310                 exit(11);
 311         }
 312         ctdb->db_persistent_check_errors = 0;
 313
 314         DEBUG(DEBUG_NOTICE,(__location__ " Recoveries finished. Running the \"startup\" event.\n"));
 315         event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 316                              timeval_current(),
 317                              ctdb_check_health, ctdb);
 318 }
 319
 320
 321 /*
 322   see if the event scripts think we are healthy
 323  */
 324 static void ctdb_check_health(struct event_context *ev, struct timed_event *te,
 325                               struct timeval t, void *private_data)
 326 {
 327         struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
 328         int ret = 0;
 329
 330         if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL ||
 331             (ctdb->monitor->monitoring_mode == CTDB_MONITORING_DISABLED && ctdb->done_startup)) {
 332                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 333                                 timeval_current_ofs(ctdb->monitor->next_interval, 0),
 334                                 ctdb_check_health, ctdb);
 335                 return;
 336         }
 337
 338         if (!ctdb->done_startup) {
 339                 ret = ctdb_event_script_callback(ctdb,
 340                                                  ctdb->monitor->monitor_context, ctdb_startup_callback,
 341                                                  ctdb, false,
 342                                                  CTDB_EVENT_STARTUP, "%s", "");
 343         } else {
 344                 int i;
 345                 int skip_monitoring = 0;
 346
 347                 if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL) {
 348                         skip_monitoring = 1;
 349                         DEBUG(DEBUG_ERR,("Skip monitoring during recovery\n"));
 350                 }
 351                 for (i=1; i<=NUM_DB_PRIORITIES; i++) {
 352                         if (ctdb->freeze_handles[i] != NULL) {
 353                                 DEBUG(DEBUG_ERR,("Skip monitoring since databases are frozen\n"));
 354                                 skip_monitoring = 1;
 355                                 break;
 356                         }
 357                 }
 358                 if (skip_monitoring != 0) {
 359                         event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 360                                         timeval_current_ofs(ctdb->monitor->next_interval, 0),
 361                                         ctdb_check_health, ctdb);
 362                         return;
 363                 } else {
 364                         ret = ctdb_event_script_callback(ctdb,
 365                                         ctdb->monitor->monitor_context, ctdb_health_callback,
 366                                         ctdb, false,
 367                                         CTDB_EVENT_MONITOR, "%s", "");
 368                 }
 369         }
 370
 371         if (ret != 0) {
 372                 DEBUG(DEBUG_ERR,("Unable to launch monitor event script\n"));
 373                 ctdb->monitor->next_interval = 5;
 374                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 375                         timeval_current_ofs(5, 0),
 376                         ctdb_check_health, ctdb);
 377         }
 378 }
 379
 380 /*
 381   (Temporaily) Disabling monitoring will stop the monitor event scripts
 382   from running   but node health checks will still occur
 383 */
 384 void ctdb_disable_monitoring(struct ctdb_context *ctdb)
 385 {
 386         ctdb->monitor->monitoring_mode = CTDB_MONITORING_DISABLED;
 387         DEBUG(DEBUG_INFO,("Monitoring has been disabled\n"));
 388 }
 389
 390 /*
 391    Re-enable running monitor events after they have been disabled
 392  */
 393 void ctdb_enable_monitoring(struct ctdb_context *ctdb)
 394 {
 395         ctdb->monitor->monitoring_mode  = CTDB_MONITORING_ACTIVE;
 396         ctdb->monitor->next_interval = 5;
 397         DEBUG(DEBUG_INFO,("Monitoring has been enabled\n"));
 398 }
 399
 400 /* stop any monitoring
 401    this should only be done when shutting down the daemon
 402 */
 403 void ctdb_stop_monitoring(struct ctdb_context *ctdb)
 404 {
 405         talloc_free(ctdb->monitor->monitor_context);
 406         ctdb->monitor->monitor_context = NULL;
 407
 408         ctdb->monitor->monitoring_mode  = CTDB_MONITORING_DISABLED;
 409         ctdb->monitor->next_interval = 5;
 410         DEBUG(DEBUG_NOTICE,("Monitoring has been stopped\n"));
 411 }
 412
 413 /*
 414   start watching for nodes that might be dead
 415  */
 416 void ctdb_start_monitoring(struct ctdb_context *ctdb)
 417 {
 418         if (ctdb->monitor != NULL) {
 419                 return;
 420         }
 421
 422         ctdb->monitor = talloc(ctdb, struct ctdb_monitor_state);
 423         CTDB_NO_MEMORY_FATAL(ctdb, ctdb->monitor);
 424
 425         ctdb->monitor->next_interval = 5;
 426
 427         ctdb->monitor->monitor_context = talloc_new(ctdb->monitor);
 428         CTDB_NO_MEMORY_FATAL(ctdb, ctdb->monitor->monitor_context);
 429
 430         event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 431                              timeval_current_ofs(1, 0),
 432                              ctdb_wait_until_recovered, ctdb);
 433
 434         ctdb->monitor->monitoring_mode  = CTDB_MONITORING_ACTIVE;
 435         DEBUG(DEBUG_NOTICE,("Monitoring has been started\n"));
 436 }
 437
 438
 439 /*
 440   modify flags on a node
 441  */
 442 int32_t ctdb_control_modflags(struct ctdb_context *ctdb, TDB_DATA indata)
 443 {
 444         struct ctdb_node_flag_change *c = (struct ctdb_node_flag_change *)indata.dptr;
 445         struct ctdb_node *node;
 446         uint32_t old_flags;
 447         int i;
 448
 449         if (c->pnn >= ctdb->num_nodes) {
 450                 DEBUG(DEBUG_ERR,(__location__ " Node %d is invalid, num_nodes :%d\n", c->pnn, ctdb->num_nodes));
 451                 return -1;
 452         }
 453
 454         node         = ctdb->nodes[c->pnn];
 455         old_flags    = node->flags;
 456         if (c->pnn != ctdb->pnn) {
 457                 c->old_flags  = node->flags;
 458         }
 459         node->flags   = c->new_flags & ~NODE_FLAGS_DISCONNECTED;
 460         node->flags  |= (c->old_flags & NODE_FLAGS_DISCONNECTED);
 461
 462         /* we dont let other nodes modify our STOPPED status */
 463         if (c->pnn == ctdb->pnn) {
 464                 node->flags &= ~NODE_FLAGS_STOPPED;
 465                 if (old_flags & NODE_FLAGS_STOPPED) {
 466                         node->flags |= NODE_FLAGS_STOPPED;
 467                 }
 468         }
 469
 470         /* we dont let other nodes modify our BANNED status */
 471         if (c->pnn == ctdb->pnn) {
 472                 node->flags &= ~NODE_FLAGS_BANNED;
 473                 if (old_flags & NODE_FLAGS_BANNED) {
 474                         node->flags |= NODE_FLAGS_BANNED;
 475                 }
 476         }
 477
 478         if (node->flags == c->old_flags) {
 479                 DEBUG(DEBUG_INFO, ("Control modflags on node %u - Unchanged - flags 0x%x\n", c->pnn, node->flags));
 480                 return 0;
 481         }
 482
 483         DEBUG(DEBUG_INFO, ("Control modflags on node %u - flags now 0x%x\n", c->pnn, node->flags));
 484
 485         if (node->flags == 0 && !ctdb->done_startup) {
 486                 DEBUG(DEBUG_ERR, (__location__ " Node %u became healthy - force recovery for startup\n",
 487                                   c->pnn));
 488                 ctdb->recovery_mode = CTDB_RECOVERY_ACTIVE;
 489         }
 490
 491         /* tell the recovery daemon something has changed */
 492         ctdb_daemon_send_message(ctdb, ctdb->pnn,
 493                                  CTDB_SRVID_SET_NODE_FLAGS, indata);
 494
 495         /* if we have become banned, we should go into recovery mode */
 496         if ((node->flags & NODE_FLAGS_BANNED) && !(c->old_flags & NODE_FLAGS_BANNED) && (node->pnn == ctdb->pnn)) {
 497                 /* make sure we are frozen */
 498                 DEBUG(DEBUG_NOTICE,("This node has been banned - forcing freeze and recovery\n"));
 499                 /* Reset the generation id to 1 to make us ignore any
 500                    REQ/REPLY CALL/DMASTER someone sends to us.
 501                    We are now banned so we shouldnt service database calls
 502                    anymore.
 503                 */
 504                 ctdb->vnn_map->generation = INVALID_GENERATION;
 505
 506                 for (i=1; i<=NUM_DB_PRIORITIES; i++) {
 507                         if (ctdb_start_freeze(ctdb, i) != 0) {
 508                                 DEBUG(DEBUG_ERR,(__location__ " Failed to freeze db priority %u\n", i));
 509                         }
 510                 }
 511                 ctdb_release_all_ips(ctdb);
 512                 ctdb->recovery_mode = CTDB_RECOVERY_ACTIVE;
 513         }
 514
 515         return 0;
 516 }
 517
 518 /*
 519   return the monitoring mode
 520  */
 521 int32_t ctdb_monitoring_mode(struct ctdb_context *ctdb)
 522 {
 523         if (ctdb->monitor == NULL) {
 524                 return CTDB_MONITORING_DISABLED;
 525         }
 526         return ctdb->monitor->monitoring_mode;
 527 }
 528