ctdb/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 "replace.h"
  22 #include "system/filesys.h"
  23 #include "system/network.h"
  24 #include "system/wait.h"
  25
  26 #include <talloc.h>
  27 #include <tevent.h>
  28
  29 #include "lib/util/debug.h"
  30 #include "lib/util/samba_util.h"
  31 #include "lib/util/util_process.h"
  32
  33 #include "ctdb_private.h"
  34
  35 #include "common/system.h"
  36 #include "common/common.h"
  37 #include "common/logging.h"
  38
  39 struct ctdb_monitor_state {
  40         TALLOC_CTX *monitor_context;
  41         uint32_t next_interval;
  42         uint32_t event_script_timeouts;
  43 };
  44
  45 static void ctdb_check_health(struct tevent_context *ev,
  46                               struct tevent_timer *te,
  47                               struct timeval t, void *private_data);
  48
  49 static int ctdb_run_notification_script_child(struct ctdb_context *ctdb, const char *event)
  50 {
  51         struct stat st;
  52         int ret;
  53         char *cmd;
  54
  55         if (stat(ctdb->notification_script, &st) != 0) {
  56                 DEBUG(DEBUG_ERR,("Could not stat notification script %s. Can not send notifications.\n", ctdb->notification_script));
  57                 return -1;
  58         }
  59         if (!(st.st_mode & S_IXUSR)) {
  60                 DEBUG(DEBUG_ERR,("Notification script %s is not executable.\n", ctdb->notification_script));
  61                 return -1;
  62         }
  63
  64         cmd = talloc_asprintf(ctdb, "%s %s\n", ctdb->notification_script, event);
  65         CTDB_NO_MEMORY(ctdb, cmd);
  66
  67         ret = system(cmd);
  68         /* if the system() call was successful, translate ret into the
  69            return code from the command
  70         */
  71         if (ret != -1) {
  72                 ret = WEXITSTATUS(ret);
  73         }
  74         if (ret != 0) {
  75                 DEBUG(DEBUG_ERR,("Notification script \"%s\" failed with error %d\n", cmd, ret));
  76         }
  77
  78         return ret;
  79 }
  80
  81 void ctdb_run_notification_script(struct ctdb_context *ctdb, const char *event)
  82 {
  83         pid_t child;
  84
  85         if (ctdb->notification_script == NULL) {
  86                 return;
  87         }
  88
  89         child = ctdb_fork(ctdb);
  90         if (child == (pid_t)-1) {
  91                 DEBUG(DEBUG_ERR,("Failed to fork() a notification child process\n"));
  92                 return;
  93         }
  94         if (child == 0) {
  95                 int ret;
  96
  97                 prctl_set_comment("ctdb_notification");
  98                 ret = ctdb_run_notification_script_child(ctdb, event);
  99                 if (ret != 0) {
 100                         DEBUG(DEBUG_ERR,(__location__ " Notification script failed\n"));
 101                 }
 102                 _exit(0);
 103         }
 104
 105         return;
 106 }
 107
 108 /*
 109   called when a health monitoring event script finishes
 110  */
 111 static void ctdb_health_callback(struct ctdb_context *ctdb, int status, void *p)
 112 {
 113         struct ctdb_node *node = ctdb->nodes[ctdb->pnn];
 114         TDB_DATA data;
 115         struct ctdb_node_flag_change c;
 116         uint32_t next_interval;
 117         int ret;
 118         TDB_DATA rddata;
 119         struct ctdb_srvid_message rd;
 120         const char *state_str = NULL;
 121
 122         c.pnn = ctdb->pnn;
 123         c.old_flags = node->flags;
 124
 125         ZERO_STRUCT(rd);
 126         rd.pnn   = ctdb->pnn;
 127         rd.srvid = 0;
 128
 129         rddata.dptr = (uint8_t *)&rd;
 130         rddata.dsize = sizeof(rd);
 131
 132         if (status == ECANCELED) {
 133                 DEBUG(DEBUG_ERR,("Monitoring event was cancelled\n"));
 134                 goto after_change_status;
 135         }
 136
 137         if (status == ETIMEDOUT) {
 138                 ctdb->monitor->event_script_timeouts++;
 139
 140                 if (ctdb->monitor->event_script_timeouts >=
 141                     ctdb->tunable.monitor_timeout_count) {
 142                         DEBUG(DEBUG_ERR,
 143                               ("Maximum monitor timeout count %u reached."
 144                                " Making node unhealthy\n",
 145                                ctdb->tunable.monitor_timeout_count));
 146                 } else {
 147                         /* We pretend this is OK. */
 148                         goto after_change_status;
 149                 }
 150         } else {
 151                 ctdb->monitor->event_script_timeouts = 0;
 152         }
 153
 154         if (status != 0 && !(node->flags & NODE_FLAGS_UNHEALTHY)) {
 155                 DEBUG(DEBUG_NOTICE,("monitor event failed - disabling node\n"));
 156                 node->flags |= NODE_FLAGS_UNHEALTHY;
 157                 ctdb->monitor->next_interval = 5;
 158
 159                 ctdb_run_notification_script(ctdb, "unhealthy");
 160         } else if (status == 0 && (node->flags & NODE_FLAGS_UNHEALTHY)) {
 161                 DEBUG(DEBUG_NOTICE,("monitor event OK - node re-enabled\n"));
 162                 node->flags &= ~NODE_FLAGS_UNHEALTHY;
 163                 ctdb->monitor->next_interval = 5;
 164
 165                 ctdb_run_notification_script(ctdb, "healthy");
 166         }
 167
 168 after_change_status:
 169         next_interval = ctdb->monitor->next_interval;
 170
 171         ctdb->monitor->next_interval *= 2;
 172         if (ctdb->monitor->next_interval > ctdb->tunable.monitor_interval) {
 173                 ctdb->monitor->next_interval = ctdb->tunable.monitor_interval;
 174         }
 175
 176         tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 177                          timeval_current_ofs(next_interval, 0),
 178                          ctdb_check_health, ctdb);
 179
 180         if (c.old_flags == node->flags) {
 181                 return;
 182         }
 183
 184         c.new_flags = node->flags;
 185
 186         data.dptr = (uint8_t *)&c;
 187         data.dsize = sizeof(c);
 188
 189         /* ask the recovery daemon to push these changes out to all nodes */
 190         ctdb_daemon_send_message(ctdb, ctdb->pnn,
 191                                  CTDB_SRVID_PUSH_NODE_FLAGS, data);
 192
 193         if (c.new_flags & NODE_FLAGS_UNHEALTHY) {
 194                 state_str = "UNHEALTHY";
 195         } else {
 196                 state_str = "HEALTHY";
 197         }
 198
 199         /* ask the recmaster to reallocate all addresses */
 200         DEBUG(DEBUG_ERR,
 201               ("Node became %s. Ask recovery master to reallocate IPs\n",
 202                state_str));
 203         ret = ctdb_daemon_send_message(ctdb, CTDB_BROADCAST_CONNECTED, CTDB_SRVID_TAKEOVER_RUN, rddata);
 204         if (ret != 0) {
 205                 DEBUG(DEBUG_ERR,
 206                       (__location__
 207                        " Failed to send IP takeover run request\n"));
 208         }
 209 }
 210
 211
 212 static void ctdb_run_startup(struct tevent_context *ev,
 213                              struct tevent_timer *te,
 214                              struct timeval t, void *private_data);
 215 /*
 216   called when the startup event script finishes
 217  */
 218 static void ctdb_startup_callback(struct ctdb_context *ctdb, int status, void *p)
 219 {
 220         if (status != 0) {
 221                 DEBUG(DEBUG_ERR,("startup event failed\n"));
 222                 tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 223                                  timeval_current_ofs(5, 0),
 224                                  ctdb_run_startup, ctdb);
 225                 return;
 226         }
 227
 228         DEBUG(DEBUG_NOTICE,("startup event OK - enabling monitoring\n"));
 229         ctdb_set_runstate(ctdb, CTDB_RUNSTATE_RUNNING);
 230         ctdb->monitor->next_interval = 2;
 231         ctdb_run_notification_script(ctdb, "startup");
 232
 233         /* tell all other nodes we've just started up */
 234         ctdb_daemon_send_control(ctdb, CTDB_BROADCAST_CONNECTED,
 235                                  0, CTDB_CONTROL_STARTUP, 0,
 236                                  CTDB_CTRL_FLAG_NOREPLY,
 237                                  tdb_null, NULL, NULL);
 238
 239         tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 240                          timeval_current_ofs(ctdb->monitor->next_interval, 0),
 241                          ctdb_check_health, ctdb);
 242 }
 243
 244 static void ctdb_run_startup(struct tevent_context *ev,
 245                              struct tevent_timer *te,
 246                              struct timeval t, void *private_data)
 247 {
 248         struct ctdb_context *ctdb = talloc_get_type(private_data,
 249                                                     struct ctdb_context);
 250         int ret;
 251
 252         /* This is necessary to avoid the "startup" event colliding
 253          * with the "ipreallocated" event from the takeover run
 254          * following the first recovery.  We might as well serialise
 255          * these things if we can.
 256          */
 257         if (ctdb->runstate < CTDB_RUNSTATE_STARTUP) {
 258                 DEBUG(DEBUG_NOTICE,
 259                       ("Not yet in startup runstate. Wait one more second\n"));
 260                 tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 261                                  timeval_current_ofs(1, 0),
 262                                  ctdb_run_startup, ctdb);
 263                 return;
 264         }
 265
 266         DEBUG(DEBUG_NOTICE,("Running the \"startup\" event.\n"));
 267         ret = ctdb_event_script_callback(ctdb,
 268                                          ctdb->monitor->monitor_context,
 269                                          ctdb_startup_callback,
 270                                          ctdb, CTDB_EVENT_STARTUP, "%s", "");
 271
 272         if (ret != 0) {
 273                 DEBUG(DEBUG_ERR,("Unable to launch startup event script\n"));
 274                 tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 275                                  timeval_current_ofs(5, 0),
 276                                  ctdb_run_startup, ctdb);
 277         }
 278 }
 279
 280 /*
 281   wait until we have finished initial recoveries before we start the
 282   monitoring events
 283  */
 284 static void ctdb_wait_until_recovered(struct tevent_context *ev,
 285                                       struct tevent_timer *te,
 286                                       struct timeval t, void *private_data)
 287 {
 288         struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
 289         int ret;
 290         static int count = 0;
 291
 292         count++;
 293
 294         if (count < 60 || count%600 == 0) {
 295                 DEBUG(DEBUG_NOTICE,("CTDB_WAIT_UNTIL_RECOVERED\n"));
 296                 if (ctdb->nodes[ctdb->pnn]->flags & NODE_FLAGS_STOPPED) {
 297                         DEBUG(DEBUG_NOTICE,("Node is STOPPED. Node will NOT recover.\n"));
 298                 }
 299         }
 300
 301         if (ctdb->vnn_map->generation == INVALID_GENERATION) {
 302                 ctdb->db_persistent_startup_generation = INVALID_GENERATION;
 303
 304                 tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 305                                  timeval_current_ofs(1, 0),
 306                                  ctdb_wait_until_recovered, ctdb);
 307                 return;
 308         }
 309
 310         if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL) {
 311                 ctdb->db_persistent_startup_generation = INVALID_GENERATION;
 312
 313                 DEBUG(DEBUG_NOTICE,(__location__ " in recovery. Wait one more second\n"));
 314                 tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 315                                  timeval_current_ofs(1, 0),
 316                                  ctdb_wait_until_recovered, ctdb);
 317                 return;
 318         }
 319
 320
 321         if (!fast_start && timeval_elapsed(&ctdb->last_recovery_finished) < (ctdb->tunable.rerecovery_timeout + 3)) {
 322                 ctdb->db_persistent_startup_generation = INVALID_GENERATION;
 323
 324                 DEBUG(DEBUG_NOTICE,(__location__ " wait for pending recoveries to end. Wait one more second.\n"));
 325
 326                 tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 327                                  timeval_current_ofs(1, 0),
 328                                  ctdb_wait_until_recovered, ctdb);
 329                 return;
 330         }
 331
 332         if (ctdb->vnn_map->generation == ctdb->db_persistent_startup_generation) {
 333                 DEBUG(DEBUG_INFO,(__location__ " skip ctdb_recheck_persistent_health() "
 334                                   "until the next recovery\n"));
 335                 tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 336                                  timeval_current_ofs(1, 0),
 337                                  ctdb_wait_until_recovered, ctdb);
 338                 return;
 339         }
 340
 341         ctdb->db_persistent_startup_generation = ctdb->vnn_map->generation;
 342         ret = ctdb_recheck_persistent_health(ctdb);
 343         if (ret != 0) {
 344                 ctdb->db_persistent_check_errors++;
 345                 if (ctdb->db_persistent_check_errors < ctdb->max_persistent_check_errors) {
 346                         DEBUG(DEBUG_ERR,
 347                               (__location__ "ctdb_recheck_persistent_health() "
 348                               "failed (%llu of %llu times) - retry later\n",
 349                               (unsigned long long)ctdb->db_persistent_check_errors,
 350                               (unsigned long long)ctdb->max_persistent_check_errors));
 351                         tevent_add_timer(ctdb->ev,
 352                                          ctdb->monitor->monitor_context,
 353                                          timeval_current_ofs(1, 0),
 354                                          ctdb_wait_until_recovered, ctdb);
 355                         return;
 356                 }
 357                 DEBUG(DEBUG_ALERT,(__location__
 358                                   "ctdb_recheck_persistent_health() failed (%llu times) - prepare shutdown\n",
 359                                   (unsigned long long)ctdb->db_persistent_check_errors));
 360                 ctdb_shutdown_sequence(ctdb, 11);
 361                 /* In case above returns due to duplicate shutdown */
 362                 return;
 363         }
 364         ctdb->db_persistent_check_errors = 0;
 365
 366         tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 367                          timeval_current(), ctdb_run_startup, ctdb);
 368 }
 369
 370
 371 /*
 372   see if the event scripts think we are healthy
 373  */
 374 static void ctdb_check_health(struct tevent_context *ev,
 375                               struct tevent_timer *te,
 376                               struct timeval t, void *private_data)
 377 {
 378         struct ctdb_context *ctdb = talloc_get_type(private_data, struct ctdb_context);
 379         bool skip_monitoring = false;
 380         int ret = 0;
 381
 382         if (ctdb->recovery_mode != CTDB_RECOVERY_NORMAL ||
 383             ctdb->nodes[ctdb->pnn]->flags & NODE_FLAGS_INACTIVE ||
 384             ctdb->runstate != CTDB_RUNSTATE_RUNNING) {
 385                 skip_monitoring = true;
 386         } else {
 387                 if (ctdb_db_all_frozen(ctdb)) {
 388                         DEBUG(DEBUG_ERR,
 389                               ("Skip monitoring since databases are frozen\n"));
 390                         skip_monitoring = true;
 391                 }
 392         }
 393
 394         if (skip_monitoring) {
 395                 tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 396                                  timeval_current_ofs(ctdb->monitor->next_interval, 0),
 397                                  ctdb_check_health, ctdb);
 398                 return;
 399         }
 400
 401         ret = ctdb_event_script_callback(ctdb,
 402                                          ctdb->monitor->monitor_context,
 403                                          ctdb_health_callback,
 404                                          ctdb, CTDB_EVENT_MONITOR, "%s", "");
 405         if (ret != 0) {
 406                 DEBUG(DEBUG_ERR,("Unable to launch monitor event script\n"));
 407                 ctdb->monitor->next_interval = 5;
 408                 tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 409                                  timeval_current_ofs(5, 0),
 410                                  ctdb_check_health, ctdb);
 411         }
 412 }
 413
 414 /* stop any monitoring
 415    this should only be done when shutting down the daemon
 416 */
 417 void ctdb_stop_monitoring(struct ctdb_context *ctdb)
 418 {
 419         if (ctdb->monitor == NULL) {
 420                 D_NOTICE("Monitoring not yet initialised\n");
 421                 return;
 422         }
 423
 424         TALLOC_FREE(ctdb->monitor->monitor_context);
 425
 426         ctdb->monitor->next_interval = 5;
 427         DEBUG(DEBUG_NOTICE,("Monitoring has been stopped\n"));
 428 }
 429
 430 /*
 431   start watching for nodes that might be dead
 432  */
 433 void ctdb_wait_for_first_recovery(struct ctdb_context *ctdb)
 434 {
 435         ctdb_set_runstate(ctdb, CTDB_RUNSTATE_FIRST_RECOVERY);
 436
 437         ctdb->monitor = talloc(ctdb, struct ctdb_monitor_state);
 438         CTDB_NO_MEMORY_FATAL(ctdb, ctdb->monitor);
 439
 440         ctdb->monitor->monitor_context = talloc_new(ctdb->monitor);
 441         CTDB_NO_MEMORY_FATAL(ctdb, ctdb->monitor->monitor_context);
 442
 443         tevent_add_timer(ctdb->ev, ctdb->monitor->monitor_context,
 444                          timeval_current_ofs(1, 0),
 445                          ctdb_wait_until_recovered, ctdb);
 446 }
 447
 448
 449 /*
 450   modify flags on a node
 451  */
 452 int32_t ctdb_control_modflags(struct ctdb_context *ctdb, TDB_DATA indata)
 453 {
 454         struct ctdb_node_flag_change *c = (struct ctdb_node_flag_change *)indata.dptr;
 455         struct ctdb_node *node;
 456         uint32_t old_flags;
 457
 458         /*
 459          * Don't let other nodes override the current node's flags.
 460          * The recovery master fetches flags from this node so there's
 461          * no need to push them back.  Doing so is racy.
 462          */
 463         if (c->pnn == ctdb->pnn) {
 464                 DBG_DEBUG("Ignoring flag changes for current node\n");
 465                 return 0;
 466         }
 467
 468         node = ctdb_find_node(ctdb, c->pnn);
 469         if (node == NULL) {
 470                 DBG_ERR("Node %u is invalid\n", c->pnn);
 471                 return -1;
 472         }
 473
 474         if (node->flags & NODE_FLAGS_DISCONNECTED) {
 475                 DBG_DEBUG("Ignoring flag changes for disconnected node\n");
 476                 return 0;
 477         }
 478
 479         /*
 480          * Remember the old flags.  We don't care what some other node
 481          * thought the old flags were - that's irrelevant.
 482          */
 483         old_flags = node->flags;
 484
 485         /*
 486          * This node tracks nodes it is connected to, so don't let
 487          * another node override this
 488          */
 489         node->flags =
 490                 (old_flags & NODE_FLAGS_DISCONNECTED) |
 491                 (c->new_flags & ~NODE_FLAGS_DISCONNECTED);
 492
 493         if (node->flags == old_flags) {
 494                 return 0;
 495         }
 496
 497         D_NOTICE("Node %u has changed flags - 0x%x -> 0x%x\n",
 498                  c->pnn,
 499                  old_flags,
 500                  node->flags);
 501
 502         if (node->flags == 0 && ctdb->runstate <= CTDB_RUNSTATE_STARTUP) {
 503                 DBG_ERR("Node %u became healthy - force recovery for startup\n",
 504                         c->pnn);
 505                 ctdb->recovery_mode = CTDB_RECOVERY_ACTIVE;
 506         }
 507
 508         return 0;
 509 }