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 = fork();
  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         const char *state_str = NULL;
 118
 119         c.pnn = ctdb->pnn;
 120         c.old_flags = node->flags;
 121
 122         rd.pnn   = ctdb->pnn;
 123         rd.srvid = CTDB_SRVID_TAKEOVER_RUN_RESPONSE;
 124
 125         rddata.dptr = (uint8_t *)&rd;
 126         rddata.dsize = sizeof(rd);
 127
 128         if (status == -ETIME) {
 129                 ctdb->event_script_timeouts++;
 130
 131                 if (ctdb->event_script_timeouts >= ctdb->tunable.script_timeout_count) {
 132                         DEBUG(DEBUG_ERR, ("Maximum timeout count %u reached for eventscript. Making node unhealthy\n", ctdb->tunable.script_timeout_count));
 133                 } else {
 134                         /* We pretend this is OK. */
 135                         goto after_change_status;
 136                 }
 137         }
 138
 139         if (status != 0 && !(node->flags & NODE_FLAGS_UNHEALTHY)) {
 140                 DEBUG(DEBUG_NOTICE,("monitor event failed - disabling node\n"));
 141                 node->flags |= NODE_FLAGS_UNHEALTHY;
 142                 ctdb->monitor->next_interval = 5;
 143
 144                 ctdb_run_notification_script(ctdb, "unhealthy");
 145         } else if (status == 0 && (node->flags & NODE_FLAGS_UNHEALTHY)) {
 146                 DEBUG(DEBUG_NOTICE,("monitor event OK - node re-enabled\n"));
 147                 node->flags &= ~NODE_FLAGS_UNHEALTHY;
 148                 ctdb->monitor->next_interval = 5;
 149
 150                 ctdb_run_notification_script(ctdb, "healthy");
 151         }
 152
 153 after_change_status:
 154         next_interval = ctdb->monitor->next_interval;
 155
 156         ctdb->monitor->next_interval *= 2;
 157         if (ctdb->monitor->next_interval > ctdb->tunable.monitor_interval) {
 158                 ctdb->monitor->next_interval = ctdb->tunable.monitor_interval;
 159         }
 160
 161         event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 162                                 timeval_current_ofs(next_interval, 0),
 163                                 ctdb_check_health, ctdb);
 164
 165         if (c.old_flags == node->flags) {
 166                 return;
 167         }
 168
 169         c.new_flags = node->flags;
 170
 171         data.dptr = (uint8_t *)&c;
 172         data.dsize = sizeof(c);
 173
 174         /* ask the recovery daemon to push these changes out to all nodes */
 175         ctdb_daemon_send_message(ctdb, ctdb->pnn,
 176                                  CTDB_SRVID_PUSH_NODE_FLAGS, data);
 177
 178         if (c.new_flags & NODE_FLAGS_UNHEALTHY) {
 179                 state_str = "UNHEALTHY";
 180         } else {
 181                 state_str = "HEALTHY";
 182         }
 183
 184         /* ask the recmaster to reallocate all addresses */
 185         DEBUG(DEBUG_ERR,("Node became %s. Ask recovery master %u to perform ip reallocation\n",
 186                          state_str, ctdb->recovery_master));
 187         ret = ctdb_daemon_send_message(ctdb, ctdb->recovery_master, CTDB_SRVID_TAKEOVER_RUN, rddata);
 188         if (ret != 0) {
 189                 DEBUG(DEBUG_ERR,(__location__ " Failed to send ip takeover run request message to %u\n", ctdb->recovery_master));
 190         }
 191 }
 192
 193
 194 /*
 195   called when the startup event script finishes
 196  */
 197 static void ctdb_startup_callback(struct ctdb_context *ctdb, int status, void *p)
 198 {
 199         if (status != 0) {
 200                 DEBUG(DEBUG_ERR,("startup event failed\n"));
 201         } else if (status == 0) {
 202                 DEBUG(DEBUG_NOTICE,("startup event OK - enabling monitoring\n"));
 203                 ctdb->done_startup = true;
 204                 ctdb->monitor->next_interval = 2;
 205                 ctdb_run_notification_script(ctdb, "startup");
 206         }
 207
 208         event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 209                         timeval_current_ofs(ctdb->monitor->next_interval, 0),
 210                         ctdb_check_health, ctdb);
 211 }
 212
 213
 214 /*
 215   wait until we have finished initial recoveries before we start the
 216   monitoring events
 217  */
 218 static void ctdb_wait_until_recovered(struct event_context *ev, struct timed_event *te,
 219                               struct timeval t, void *private_data)
 220 {
 221         struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
 222         int ret;
 223
 224         DEBUG(DEBUG_NOTICE,("CTDB_WAIT_UNTIL_RECOVERED\n"));
 225
 226         if (ctdb->vnn_map->generation == INVALID_GENERATION) {
 227                 ctdb->db_persistent_startup_generation = INVALID_GENERATION;
 228
 229                 DEBUG(DEBUG_NOTICE,(__location__ " generation is INVALID. Wait one more second\n"));
 230                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 231                                      timeval_current_ofs(1, 0),
 232                                      ctdb_wait_until_recovered, ctdb);
 233                 return;
 234         }
 235
 236         if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL) {
 237                 ctdb->db_persistent_startup_generation = INVALID_GENERATION;
 238
 239                 DEBUG(DEBUG_NOTICE,(__location__ " in recovery. Wait one more second\n"));
 240                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 241                                      timeval_current_ofs(1, 0),
 242                                      ctdb_wait_until_recovered, ctdb);
 243                 return;
 244         }
 245
 246
 247         if (!fast_start && timeval_elapsed(&ctdb->last_recovery_finished) < (ctdb->tunable.rerecovery_timeout + 3)) {
 248                 ctdb->db_persistent_startup_generation = INVALID_GENERATION;
 249
 250                 DEBUG(DEBUG_NOTICE,(__location__ " wait for pending recoveries to end. Wait one more second.\n"));
 251
 252                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 253                                      timeval_current_ofs(1, 0),
 254                                      ctdb_wait_until_recovered, ctdb);
 255                 return;
 256         }
 257
 258         if (ctdb->vnn_map->generation == ctdb->db_persistent_startup_generation) {
 259                 DEBUG(DEBUG_INFO,(__location__ " skip ctdb_recheck_persistent_health() "
 260                                   "until the next recovery\n"));
 261                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 262                                      timeval_current_ofs(1, 0),
 263                                      ctdb_wait_until_recovered, ctdb);
 264                 return;
 265         }
 266
 267         ctdb->db_persistent_startup_generation = ctdb->vnn_map->generation;
 268         ret = ctdb_recheck_persistent_health(ctdb);
 269         if (ret != 0) {
 270                 ctdb->db_persistent_check_errors++;
 271                 if (ctdb->db_persistent_check_errors < ctdb->max_persistent_check_errors) {
 272                         DEBUG(ctdb->db_persistent_check_errors==1?DEBUG_ERR:DEBUG_WARNING,
 273                               (__location__ "ctdb_recheck_persistent_health() "
 274                               "failed (%llu of %llu times) - retry later\n",
 275                               (unsigned long long)ctdb->db_persistent_check_errors,
 276                               (unsigned long long)ctdb->max_persistent_check_errors));
 277                         event_add_timed(ctdb->ev,
 278                                         ctdb->monitor->monitor_context,
 279                                         timeval_current_ofs(1, 0),
 280                                         ctdb_wait_until_recovered, ctdb);
 281                         return;
 282                 }
 283                 DEBUG(DEBUG_ALERT,(__location__
 284                                   "ctdb_recheck_persistent_health() failed (%llu times) - prepare shutdown\n",
 285                                   (unsigned long long)ctdb->db_persistent_check_errors));
 286                 ctdb_stop_recoverd(ctdb);
 287                 ctdb_stop_keepalive(ctdb);
 288                 ctdb_stop_monitoring(ctdb);
 289                 ctdb_release_all_ips(ctdb);
 290                 if (ctdb->methods != NULL) {
 291                         ctdb->methods->shutdown(ctdb);
 292                 }
 293                 ctdb_event_script(ctdb, CTDB_EVENT_SHUTDOWN);
 294                 DEBUG(DEBUG_ALERT,("ctdb_recheck_persistent_health() failed - Stopping CTDB daemon\n"));
 295                 exit(11);
 296         }
 297         ctdb->db_persistent_check_errors = 0;
 298         DEBUG(DEBUG_NOTICE,(__location__
 299                            "ctdb_start_monitoring: ctdb_recheck_persistent_health() OK\n"));
 300
 301         DEBUG(DEBUG_NOTICE,(__location__ " Recoveries finished. Running the \"startup\" event.\n"));
 302         event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 303                              timeval_current(),
 304                              ctdb_check_health, ctdb);
 305 }
 306
 307
 308 /*
 309   see if the event scripts think we are healthy
 310  */
 311 static void ctdb_check_health(struct event_context *ev, struct timed_event *te,
 312                               struct timeval t, void *private_data)
 313 {
 314         struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
 315         int ret = 0;
 316
 317         if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL ||
 318             (ctdb->monitor->monitoring_mode == CTDB_MONITORING_DISABLED && ctdb->done_startup)) {
 319                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 320                                 timeval_current_ofs(ctdb->monitor->next_interval, 0),
 321                                 ctdb_check_health, ctdb);
 322                 return;
 323         }
 324
 325         if (!ctdb->done_startup) {
 326                 ret = ctdb_event_script_callback(ctdb,
 327                                                  ctdb->monitor->monitor_context, ctdb_startup_callback,
 328                                                  ctdb, false,
 329                                                  CTDB_EVENT_STARTUP, "%s", "");
 330         } else {
 331                 int i;
 332                 int skip_monitoring = 0;
 333
 334                 if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL) {
 335                         skip_monitoring = 1;
 336                         DEBUG(DEBUG_ERR,("Skip monitoring during recovery\n"));
 337                 }
 338                 for (i=1; i<=NUM_DB_PRIORITIES; i++) {
 339                         if (ctdb->freeze_handles[i] != NULL) {
 340                                 DEBUG(DEBUG_ERR,("Skip monitoring since databases are frozen\n"));
 341                                 skip_monitoring = 1;
 342                                 break;
 343                         }
 344                 }
 345                 if (skip_monitoring != 0) {
 346                         event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 347                                         timeval_current_ofs(ctdb->monitor->next_interval, 0),
 348                                         ctdb_check_health, ctdb);
 349                         return;
 350                 } else {
 351                         ret = ctdb_event_script_callback(ctdb,
 352                                         ctdb->monitor->monitor_context, ctdb_health_callback,
 353                                         ctdb, false,
 354                                         CTDB_EVENT_MONITOR, "%s", "");
 355                 }
 356         }
 357
 358         if (ret != 0) {
 359                 DEBUG(DEBUG_ERR,("Unable to launch monitor event script\n"));
 360                 ctdb->monitor->next_interval = 5;
 361                 event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 362                         timeval_current_ofs(5, 0),
 363                         ctdb_check_health, ctdb);
 364         }
 365 }
 366
 367 /*
 368   (Temporaily) Disabling monitoring will stop the monitor event scripts
 369   from running   but node health checks will still occur
 370 */
 371 void ctdb_disable_monitoring(struct ctdb_context *ctdb)
 372 {
 373         ctdb->monitor->monitoring_mode = CTDB_MONITORING_DISABLED;
 374         DEBUG(DEBUG_INFO,("Monitoring has been disabled\n"));
 375 }
 376
 377 /*
 378    Re-enable running monitor events after they have been disabled
 379  */
 380 void ctdb_enable_monitoring(struct ctdb_context *ctdb)
 381 {
 382         ctdb->monitor->monitoring_mode  = CTDB_MONITORING_ACTIVE;
 383         ctdb->monitor->next_interval = 5;
 384         DEBUG(DEBUG_INFO,("Monitoring has been enabled\n"));
 385 }
 386
 387 /* stop any monitoring
 388    this should only be done when shutting down the daemon
 389 */
 390 void ctdb_stop_monitoring(struct ctdb_context *ctdb)
 391 {
 392         talloc_free(ctdb->monitor->monitor_context);
 393         ctdb->monitor->monitor_context = NULL;
 394
 395         ctdb->monitor->monitoring_mode  = CTDB_MONITORING_DISABLED;
 396         ctdb->monitor->next_interval = 5;
 397         DEBUG(DEBUG_NOTICE,("Monitoring has been stopped\n"));
 398 }
 399
 400 /*
 401   start watching for nodes that might be dead
 402  */
 403 void ctdb_start_monitoring(struct ctdb_context *ctdb)
 404 {
 405         if (ctdb->monitor != NULL) {
 406                 return;
 407         }
 408
 409         ctdb->monitor = talloc(ctdb, struct ctdb_monitor_state);
 410         CTDB_NO_MEMORY_FATAL(ctdb, ctdb->monitor);
 411
 412         ctdb->monitor->next_interval = 5;
 413
 414         ctdb->monitor->monitor_context = talloc_new(ctdb->monitor);
 415         CTDB_NO_MEMORY_FATAL(ctdb, ctdb->monitor->monitor_context);
 416
 417         event_add_timed(ctdb->ev, ctdb->monitor->monitor_context,
 418                              timeval_current_ofs(1, 0),
 419                              ctdb_wait_until_recovered, ctdb);
 420
 421         ctdb->monitor->monitoring_mode  = CTDB_MONITORING_ACTIVE;
 422         DEBUG(DEBUG_NOTICE,("Monitoring has been started\n"));
 423 }
 424
 425
 426 /*
 427   modify flags on a node
 428  */
 429 int32_t ctdb_control_modflags(struct ctdb_context *ctdb, TDB_DATA indata)
 430 {
 431         struct ctdb_node_flag_change *c = (struct ctdb_node_flag_change *)indata.dptr;
 432         struct ctdb_node *node;
 433         uint32_t old_flags;
 434
 435         if (c->pnn >= ctdb->num_nodes) {
 436                 DEBUG(DEBUG_ERR,(__location__ " Node %d is invalid, num_nodes :%d\n", c->pnn, ctdb->num_nodes));
 437                 return -1;
 438         }
 439
 440         node         = ctdb->nodes[c->pnn];
 441         old_flags    = node->flags;
 442         if (c->pnn != ctdb->pnn) {
 443                 c->old_flags  = node->flags;
 444         }
 445         node->flags   = c->new_flags & ~NODE_FLAGS_DISCONNECTED;
 446         node->flags  |= (c->old_flags & NODE_FLAGS_DISCONNECTED);
 447
 448         /* we dont let other nodes modify our STOPPED status */
 449         if (c->pnn == ctdb->pnn) {
 450                 node->flags &= ~NODE_FLAGS_STOPPED;
 451                 if (old_flags & NODE_FLAGS_STOPPED) {
 452                         node->flags |= NODE_FLAGS_STOPPED;
 453                 }
 454         }
 455
 456         /* we dont let other nodes modify our BANNED status */
 457         if (c->pnn == ctdb->pnn) {
 458                 node->flags &= ~NODE_FLAGS_BANNED;
 459                 if (old_flags & NODE_FLAGS_BANNED) {
 460                         node->flags |= NODE_FLAGS_BANNED;
 461                 }
 462         }
 463
 464         if (node->flags == c->old_flags) {
 465                 DEBUG(DEBUG_INFO, ("Control modflags on node %u - Unchanged - flags 0x%x\n", c->pnn, node->flags));
 466                 return 0;
 467         }
 468
 469         DEBUG(DEBUG_INFO, ("Control modflags on node %u - flags now 0x%x\n", c->pnn, node->flags));
 470
 471         if (node->flags == 0 && !ctdb->done_startup) {
 472                 DEBUG(DEBUG_ERR, (__location__ " Node %u became healthy - force recovery for startup\n",
 473                                   c->pnn));
 474                 ctdb->recovery_mode = CTDB_RECOVERY_ACTIVE;
 475         }
 476
 477         /* tell the recovery daemon something has changed */
 478         ctdb_daemon_send_message(ctdb, ctdb->pnn,
 479                                  CTDB_SRVID_SET_NODE_FLAGS, indata);
 480
 481         /* if we have become banned, we should go into recovery mode */
 482         if ((node->flags & NODE_FLAGS_BANNED) && !(c->old_flags & NODE_FLAGS_BANNED) && (node->pnn == ctdb->pnn)) {
 483                 return ctdb_local_node_got_banned(ctdb);
 484         }
 485
 486         return 0;
 487 }
 488
 489 /*
 490   return the monitoring mode
 491  */
 492 int32_t ctdb_monitoring_mode(struct ctdb_context *ctdb)
 493 {
 494         if (ctdb->monitor == NULL) {
 495                 return CTDB_MONITORING_DISABLED;
 496         }
 497         return ctdb->monitor->monitoring_mode;
 498 }
 499