summaryrefslogtreecommitdiffstats
path: root/health/health.c
blob: f92a1ba6b0f5879e5f7a70d29f81762b0831f81d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
// SPDX-License-Identifier: GPL-3.0-or-later

#include "health.h"

struct health_cmdapi_thread_status {
    int status;
    ;
    struct rusage rusage;
};

unsigned int default_health_enabled = 1;

// ----------------------------------------------------------------------------
// health initialization

inline char *health_user_config_dir(void) {
    char buffer[FILENAME_MAX + 1];
    snprintfz(buffer, FILENAME_MAX, "%s/health.d", netdata_configured_user_config_dir);
    return config_get(CONFIG_SECTION_HEALTH, "health configuration directory", buffer);
}

inline char *health_stock_config_dir(void) {
    char buffer[FILENAME_MAX + 1];
    snprintfz(buffer, FILENAME_MAX, "%s/health.d", netdata_configured_stock_config_dir);
    return config_get(CONFIG_SECTION_HEALTH, "stock health configuration directory", buffer);
}

void health_init(void) {
    debug(D_HEALTH, "Health configuration initializing");

    if(!(default_health_enabled = (unsigned int)config_get_boolean(CONFIG_SECTION_HEALTH, "enabled", default_health_enabled))) {
        debug(D_HEALTH, "Health is disabled.");
        return;
    }
}

// ----------------------------------------------------------------------------
// re-load health configuration

void health_reload_host(RRDHOST *host) {
    if(unlikely(!host->health_enabled))
        return;

    char *user_path = health_user_config_dir();
    char *stock_path = health_stock_config_dir();

    // free all running alarms
    rrdhost_wrlock(host);

    while(host->templates)
        rrdcalctemplate_unlink_and_free(host, host->templates);

    while(host->alarms)
        rrdcalc_unlink_and_free(host, host->alarms);

    rrdhost_unlock(host);

    // invalidate all previous entries in the alarm log
    ALARM_ENTRY *t;
    for(t = host->health_log.alarms ; t ; t = t->next) {
        if(t->new_status != RRDCALC_STATUS_REMOVED)
            t->flags |= HEALTH_ENTRY_FLAG_UPDATED;
    }

    rrdhost_rdlock(host);
    // reset all thresholds to all charts
    RRDSET *st;
    rrdset_foreach_read(st, host) {
        st->green = NAN;
        st->red = NAN;
    }
    rrdhost_unlock(host);

    // load the new alarms
    rrdhost_wrlock(host);
    health_readdir(host, user_path, stock_path, NULL);

    // link the loaded alarms to their charts
    rrdset_foreach_write(st, host) {
        rrdsetcalc_link_matching(st);
        rrdcalctemplate_link_matching(st);
    }

    rrdhost_unlock(host);
}

void health_reload(void) {

    rrd_rdlock();

    RRDHOST *host;
    rrdhost_foreach_read(host)
        health_reload_host(host);

    rrd_unlock();
}

// ----------------------------------------------------------------------------
// health main thread and friends

static inline RRDCALC_STATUS rrdcalc_value2status(calculated_number n) {
    if(isnan(n) || isinf(n)) return RRDCALC_STATUS_UNDEFINED;
    if(n) return RRDCALC_STATUS_RAISED;
    return RRDCALC_STATUS_CLEAR;
}

#define ALARM_EXEC_COMMAND_LENGTH 8192

static inline void health_alarm_execute(RRDHOST *host, ALARM_ENTRY *ae) {
    ae->flags |= HEALTH_ENTRY_FLAG_PROCESSED;

    if(unlikely(ae->new_status < RRDCALC_STATUS_CLEAR)) {
        // do not send notifications for internal statuses
        debug(D_HEALTH, "Health not sending notification for alarm '%s.%s' status %s (internal statuses)", ae->chart, ae->name, rrdcalc_status2string(ae->new_status));
        goto done;
    }

    if(unlikely(ae->new_status <= RRDCALC_STATUS_CLEAR && (ae->flags & HEALTH_ENTRY_FLAG_NO_CLEAR_NOTIFICATION))) {
        // do not send notifications for disabled statuses
        debug(D_HEALTH, "Health not sending notification for alarm '%s.%s' status %s (it has no-clear-notification enabled)", ae->chart, ae->name, rrdcalc_status2string(ae->new_status));
        // mark it as run, so that we will send the same alarm if it happens again
        goto done;
    }

    // find the previous notification for the same alarm
    // which we have run the exec script
    // exception: alarms with HEALTH_ENTRY_FLAG_NO_CLEAR_NOTIFICATION set
    if(likely(!(ae->flags & HEALTH_ENTRY_FLAG_NO_CLEAR_NOTIFICATION))) {
        uint32_t id = ae->alarm_id;
        ALARM_ENTRY *t;
        for(t = ae->next; t ; t = t->next) {
            if(t->alarm_id == id && t->flags & HEALTH_ENTRY_FLAG_EXEC_RUN)
                break;
        }

        if(likely(t)) {
            // we have executed this alarm notification in the past
            if(t && t->new_status == ae->new_status) {
                // don't send the notification for the same status again
                debug(D_HEALTH, "Health not sending again notification for alarm '%s.%s' status %s", ae->chart, ae->name
                      , rrdcalc_status2string(ae->new_status));
                goto done;
            }
        }
        else {
            // we have not executed this alarm notification in the past
            // so, don't send CLEAR notifications
            if(unlikely(ae->new_status == RRDCALC_STATUS_CLEAR)) {
                debug(D_HEALTH, "Health not sending notification for first initialization of alarm '%s.%s' status %s"
                      , ae->chart, ae->name, rrdcalc_status2string(ae->new_status));
                goto done;
            }
        }
    }

    // Check if alarm notifications are silenced
    if (ae->flags & HEALTH_ENTRY_FLAG_SILENCED) {
        info("Health not sending notification for alarm '%s.%s' status %s (command API has disabled notifications)", ae->chart, ae->name, rrdcalc_status2string(ae->new_status));
        goto done;
    }

    static char command_to_run[ALARM_EXEC_COMMAND_LENGTH + 1];
    pid_t command_pid;

    const char *exec      = (ae->exec)      ? ae->exec      : host->health_default_exec;
    const char *recipient = (ae->recipient) ? ae->recipient : host->health_default_recipient;

	int n_warn=0, n_crit=0;
	RRDCALC *rc;
    EVAL_EXPRESSION *expr=NULL;

	for(rc = host->alarms; rc ; rc = rc->next) {
		if(unlikely(!rc->rrdset || !rc->rrdset->last_collected_time.tv_sec))
			continue;

		if(unlikely(rc->status == RRDCALC_STATUS_WARNING)) {
            n_warn++;
            if (ae->alarm_id == rc->id)
                expr=rc->warning;
        } else if (unlikely(rc->status == RRDCALC_STATUS_CRITICAL)) {
            n_crit++;
            if (ae->alarm_id == rc->id)
                expr=rc->critical;
        } else if (unlikely(rc->status == RRDCALC_STATUS_CLEAR)) {
            if (ae->alarm_id == rc->id)
                expr=rc->warning;
		}
	}

    snprintfz(command_to_run, ALARM_EXEC_COMMAND_LENGTH, "exec %s '%s' '%s' '%u' '%u' '%u' '%lu' '%s' '%s' '%s' '%s' '%s' '" CALCULATED_NUMBER_FORMAT_ZERO "' '" CALCULATED_NUMBER_FORMAT_ZERO "' '%s' '%u' '%u' '%s' '%s' '%s' '%s' '%s' '%s' '%d' '%d'",
              exec,
              recipient,
              host->registry_hostname,
              ae->unique_id,
              ae->alarm_id,
              ae->alarm_event_id,
              (unsigned long)ae->when,
              ae->name,
              ae->chart?ae->chart:"NOCHART",
              ae->family?ae->family:"NOFAMILY",
              rrdcalc_status2string(ae->new_status),
              rrdcalc_status2string(ae->old_status),
              ae->new_value,
              ae->old_value,
              ae->source?ae->source:"UNKNOWN",
              (uint32_t)ae->duration,
              (uint32_t)ae->non_clear_duration,
              ae->units?ae->units:"",
              ae->info?ae->info:"",
              ae->new_value_string,
              ae->old_value_string,
              (expr && expr->source)?expr->source:"NOSOURCE",
              (expr && expr->error_msg)?buffer_tostring(expr->error_msg):"NOERRMSG",
              n_warn,
              n_crit
    );

    ae->flags |= HEALTH_ENTRY_FLAG_EXEC_RUN;
    ae->exec_run_timestamp = now_realtime_sec();

    debug(D_HEALTH, "executing command '%s'", command_to_run);
    FILE *fp = mypopen(command_to_run, &command_pid);
    if(!fp) {
        error("HEALTH: Cannot popen(\"%s\", \"r\").", command_to_run);
        goto done;
    }
    debug(D_HEALTH, "HEALTH reading from command (discarding command's output)");
    char buffer[100 + 1];
    while(fgets(buffer, 100, fp) != NULL) ;
    ae->exec_code = mypclose(fp, command_pid);
    debug(D_HEALTH, "done executing command - returned with code %d", ae->exec_code);

    if(ae->exec_code != 0)
        ae->flags |= HEALTH_ENTRY_FLAG_EXEC_FAILED;

done:
    health_alarm_log_save(host, ae);
}

static inline void health_process_notifications(RRDHOST *host, ALARM_ENTRY *ae) {
    debug(D_HEALTH, "Health alarm '%s.%s' = " CALCULATED_NUMBER_FORMAT_AUTO " - changed status from %s to %s",
         ae->chart?ae->chart:"NOCHART", ae->name,
         ae->new_value,
         rrdcalc_status2string(ae->old_status),
         rrdcalc_status2string(ae->new_status)
    );

    health_alarm_execute(host, ae);
}

static inline void health_alarm_log_process(RRDHOST *host) {
    uint32_t first_waiting = (host->health_log.alarms)?host->health_log.alarms->unique_id:0;
    time_t now = now_realtime_sec();

    netdata_rwlock_rdlock(&host->health_log.alarm_log_rwlock);

    ALARM_ENTRY *ae;
    for(ae = host->health_log.alarms; ae && ae->unique_id >= host->health_last_processed_id ; ae = ae->next) {
        if(unlikely(
            !(ae->flags & HEALTH_ENTRY_FLAG_PROCESSED) &&
            !(ae->flags & HEALTH_ENTRY_FLAG_UPDATED)
            )) {

            if(unlikely(ae->unique_id < first_waiting))
                first_waiting = ae->unique_id;

            if(likely(now >= ae->delay_up_to_timestamp))
                health_process_notifications(host, ae);
        }
    }

    // remember this for the next iteration
    host->health_last_processed_id = first_waiting;

    netdata_rwlock_unlock(&host->health_log.alarm_log_rwlock);

    if(host->health_log.count <= host->health_log.max)
        return;

    // cleanup excess entries in the log
    netdata_rwlock_wrlock(&host->health_log.alarm_log_rwlock);

    ALARM_ENTRY *last = NULL;
    unsigned int count = host->health_log.max * 2 / 3;
    for(ae = host->health_log.alarms; ae && count ; count--, last = ae, ae = ae->next) ;

    if(ae && last && last->next == ae)
        last->next = NULL;
    else
        ae = NULL;

    while(ae) {
        debug(D_HEALTH, "Health removing alarm log entry with id: %u", ae->unique_id);

        ALARM_ENTRY *t = ae->next;

        health_alarm_log_free_one_nochecks_nounlink(ae);

        ae = t;
        host->health_log.count--;
    }

    netdata_rwlock_unlock(&host->health_log.alarm_log_rwlock);
}

static inline int rrdcalc_isrunnable(RRDCALC *rc, time_t now, time_t *next_run) {
    if(unlikely(!rc->rrdset)) {
        debug(D_HEALTH, "Health not running alarm '%s.%s'. It is not linked to a chart.", rc->chart?rc->chart:"NOCHART", rc->name);
        return 0;
    }

    if(unlikely(rc->next_update > now)) {
        if (unlikely(*next_run > rc->next_update)) {
            // update the next_run time of the main loop
            // to run this alarm precisely the time required
            *next_run = rc->next_update;
        }

        debug(D_HEALTH, "Health not examining alarm '%s.%s' yet (will do in %d secs).", rc->chart?rc->chart:"NOCHART", rc->name, (int) (rc->next_update - now));
        return 0;
    }

    if(unlikely(!rc->update_every)) {
        debug(D_HEALTH, "Health not running alarm '%s.%s'. It does not have an update frequency", rc->chart?rc->chart:"NOCHART", rc->name);
        return 0;
    }

    if(unlikely(rrdset_flag_check(rc->rrdset, RRDSET_FLAG_OBSOLETE))) {
        debug(D_HEALTH, "Health not running alarm '%s.%s'. The chart has been marked as obsolete", rc->chart?rc->chart:"NOCHART", rc->name);
        return 0;
    }

    if(unlikely(!rrdset_flag_check(rc->rrdset, RRDSET_FLAG_ENABLED))) {
        debug(D_HEALTH, "Health not running alarm '%s.%s'. The chart is not enabled", rc->chart?rc->chart:"NOCHART", rc->name);
        return 0;
    }

    if(unlikely(!rc->rrdset->last_collected_time.tv_sec || rc->rrdset->counter_done < 2)) {
        debug(D_HEALTH, "Health not running alarm '%s.%s'. Chart is not fully collected yet.", rc->chart?rc->chart:"NOCHART", rc->name);
        return 0;
    }

    int update_every = rc->rrdset->update_every;
    time_t first = rrdset_first_entry_t(rc->rrdset);
    time_t last = rrdset_last_entry_t(rc->rrdset);

    if(unlikely(now + update_every < first /* || now - update_every > last */)) {
        debug(D_HEALTH
              , "Health not examining alarm '%s.%s' yet (wanted time is out of bounds - we need %lu but got %lu - %lu)."
              , rc->chart ? rc->chart : "NOCHART", rc->name, (unsigned long) now, (unsigned long) first
              , (unsigned long) last);
        return 0;
    }

    if(RRDCALC_HAS_DB_LOOKUP(rc)) {
        time_t needed = now + rc->before + rc->after;

        if(needed + update_every < first || needed - update_every > last) {
            debug(D_HEALTH
                  , "Health not examining alarm '%s.%s' yet (not enough data yet - we need %lu but got %lu - %lu)."
                  , rc->chart ? rc->chart : "NOCHART", rc->name, (unsigned long) needed, (unsigned long) first
                  , (unsigned long) last);
            return 0;
        }
    }

    return 1;
}

static inline int check_if_resumed_from_suspention(void) {
    static usec_t last_realtime = 0, last_monotonic = 0;
    usec_t realtime = now_realtime_usec(), monotonic = now_monotonic_usec();
    int ret = 0;

    // detect if monotonic and realtime have twice the difference
    // in which case we assume the system was just waken from hibernation

    if(last_realtime && last_monotonic && realtime - last_realtime > 2 * (monotonic - last_monotonic))
        ret = 1;

    last_realtime = realtime;
    last_monotonic = monotonic;

    return ret;
}

static void health_main_cleanup(void *ptr) {
    struct netdata_static_thread *static_thread = (struct netdata_static_thread *)ptr;
    static_thread->enabled = NETDATA_MAIN_THREAD_EXITING;

    info("cleaning up...");

    static_thread->enabled = NETDATA_MAIN_THREAD_EXITED;
}

SILENCE_TYPE check_silenced(RRDCALC *rc, char* host, SILENCERS *silencers) {
	SILENCER *s;
    debug(D_HEALTH, "Checking if alarm was silenced via the command API. Alarm info name:%s context:%s chart:%s host:%s family:%s",
            rc->name, (rc->rrdset)?rc->rrdset->context:"", rc->chart, host, (rc->rrdset)?rc->rrdset->family:"");

    for (s = silencers->silencers; s!=NULL; s=s->next){
        if (
                (!s->alarms_pattern || (rc->name && s->alarms_pattern && simple_pattern_matches(s->alarms_pattern,rc->name))) &&
                (!s->contexts_pattern || (rc->rrdset && rc->rrdset->context && s->contexts_pattern && simple_pattern_matches(s->contexts_pattern,rc->rrdset->context))) &&
                (!s->hosts_pattern || (host && s->hosts_pattern && simple_pattern_matches(s->hosts_pattern,host))) &&
                (!s->charts_pattern || (rc->chart && s->charts_pattern && simple_pattern_matches(s->charts_pattern,rc->chart))) &&
                (!s->families_pattern || (rc->rrdset && rc->rrdset->family && s->families_pattern && simple_pattern_matches(s->families_pattern,rc->rrdset->family)))
                ) {
            debug(D_HEALTH, "Alarm matches command API silence entry %s:%s:%s:%s:%s", s->alarms,s->charts, s->contexts, s->hosts, s->families);
            if (unlikely(silencers->stype == STYPE_NONE)) {
                debug(D_HEALTH, "Alarm %s matched a silence entry, but no SILENCE or DISABLE command was issued via the command API. The match has no effect.", rc->name);
            } else {
                debug(D_HEALTH, "Alarm %s via the command API - name:%s context:%s chart:%s host:%s family:%s"
                		, (silencers->stype==STYPE_DISABLE_ALARMS)?"Disabled":"Silenced"
                        , rc->name
                        , (rc->rrdset)?rc->rrdset->context:""
                        , rc->chart
                        , host
                        , (rc->rrdset)?rc->rrdset->family:""
                        );
            }
            return silencers->stype;
        }
    }
    return STYPE_NONE;
}

int update_disabled_silenced(RRDHOST *host, RRDCALC *rc) {
	uint32_t rrdcalc_flags_old = rc->rrdcalc_flags;
	// Clear the flags
	rc->rrdcalc_flags &= ~(RRDCALC_FLAG_DISABLED | RRDCALC_FLAG_SILENCED);
	if (unlikely(silencers->all_alarms)) {
		if (silencers->stype == STYPE_DISABLE_ALARMS) rc->rrdcalc_flags |= RRDCALC_FLAG_DISABLED;
		else if (silencers->stype == STYPE_SILENCE_NOTIFICATIONS) rc->rrdcalc_flags |= RRDCALC_FLAG_SILENCED;
	} else {
		SILENCE_TYPE st = check_silenced(rc, host->hostname, silencers);
		if (st == STYPE_DISABLE_ALARMS) rc->rrdcalc_flags |= RRDCALC_FLAG_DISABLED;
		else if (st == STYPE_SILENCE_NOTIFICATIONS) rc->rrdcalc_flags |= RRDCALC_FLAG_SILENCED;
	}

	if (rrdcalc_flags_old != rc->rrdcalc_flags) {
		info("Alarm silencing changed for host '%s' alarm '%s': Disabled %s->%s Silenced %s->%s",
				host->hostname,
				rc->name,
			 (rrdcalc_flags_old & RRDCALC_FLAG_DISABLED)?"true":"false",
			 (rc->rrdcalc_flags & RRDCALC_FLAG_DISABLED)?"true":"false",
			 (rrdcalc_flags_old & RRDCALC_FLAG_SILENCED)?"true":"false",
			 (rc->rrdcalc_flags & RRDCALC_FLAG_SILENCED)?"true":"false"
		);
	}
	if (rc->rrdcalc_flags & RRDCALC_FLAG_DISABLED)
		return 1;
	else
		return 0;
}

void *health_main(void *ptr) {
    netdata_thread_cleanup_push(health_main_cleanup, ptr);

    int min_run_every = (int)config_get_number(CONFIG_SECTION_HEALTH, "run at least every seconds", 10);
    if(min_run_every < 1) min_run_every = 1;

    time_t now                = now_realtime_sec();
    time_t hibernation_delay  = config_get_number(CONFIG_SECTION_HEALTH, "postpone alarms during hibernation for seconds", 60);

    unsigned int loop = 0;

    silencers =  mallocz(sizeof(SILENCERS));
    silencers->all_alarms=0;
    silencers->stype=STYPE_NONE;
    silencers->silencers=NULL;

    while(!netdata_exit) {
		loop++;
		debug(D_HEALTH, "Health monitoring iteration no %u started", loop);

		int runnable = 0, apply_hibernation_delay = 0;
		time_t next_run = now + min_run_every;
		RRDCALC *rc;

		if (unlikely(check_if_resumed_from_suspention())) {
			apply_hibernation_delay = 1;

			info("Postponing alarm checks for %ld seconds, because it seems that the system was just resumed from suspension.",
				 hibernation_delay
			);
		}

		if (unlikely(silencers->all_alarms && silencers->stype == STYPE_DISABLE_ALARMS)) {
			static int logged=0;
			if (!logged) {
				info("Skipping health checks, because all alarms are disabled via a %s command.",
					 HEALTH_CMDAPI_CMD_DISABLEALL);
				logged = 1;
			}
		}

		rrd_rdlock();

		RRDHOST *host;
		rrdhost_foreach_read(host) {
			if (unlikely(!host->health_enabled))
				continue;

			if (unlikely(apply_hibernation_delay)) {

				info("Postponing health checks for %ld seconds, on host '%s'.", hibernation_delay, host->hostname
				);

				host->health_delay_up_to = now + hibernation_delay;
			}

			if (unlikely(host->health_delay_up_to)) {
				if (unlikely(now < host->health_delay_up_to))
					continue;

				info("Resuming health checks on host '%s'.", host->hostname);
				host->health_delay_up_to = 0;
			}

			rrdhost_rdlock(host);

			// the first loop is to lookup values from the db
			for (rc = host->alarms; rc; rc = rc->next) {

				if (update_disabled_silenced(host, rc))
					continue;

				if (unlikely(!rrdcalc_isrunnable(rc, now, &next_run))) {
					if (unlikely(rc->rrdcalc_flags & RRDCALC_FLAG_RUNNABLE))
						rc->rrdcalc_flags &= ~RRDCALC_FLAG_RUNNABLE;
					continue;
				}

				runnable++;
				rc->old_value = rc->value;
				rc->rrdcalc_flags |= RRDCALC_FLAG_RUNNABLE;

				// ------------------------------------------------------------
				// if there is database lookup, do it

				if (unlikely(RRDCALC_HAS_DB_LOOKUP(rc))) {
					/* time_t old_db_timestamp = rc->db_before; */
					int value_is_null = 0;

					int ret = rrdset2value_api_v1(rc->rrdset, NULL, &rc->value, rc->dimensions, 1, rc->after,
												  rc->before, rc->group, 0, rc->options, &rc->db_after,
												  &rc->db_before, &value_is_null
					);

					if (unlikely(ret != 200)) {
						// database lookup failed
						rc->value = NAN;
						rc->rrdcalc_flags |= RRDCALC_FLAG_DB_ERROR;

						debug(D_HEALTH, "Health on host '%s', alarm '%s.%s': database lookup returned error %d",
							  host->hostname, rc->chart ? rc->chart : "NOCHART", rc->name, ret
						);
					} else
						rc->rrdcalc_flags &= ~RRDCALC_FLAG_DB_ERROR;

					/* - RRDCALC_FLAG_DB_STALE not currently used
					if (unlikely(old_db_timestamp == rc->db_before)) {
						// database is stale

						debug(D_HEALTH, "Health on host '%s', alarm '%s.%s': database is stale", host->hostname, rc->chart?rc->chart:"NOCHART", rc->name);

						if (unlikely(!(rc->rrdcalc_flags & RRDCALC_FLAG_DB_STALE))) {
							rc->rrdcalc_flags |= RRDCALC_FLAG_DB_STALE;
							error("Health on host '%s', alarm '%s.%s': database is stale", host->hostname, rc->chart?rc->chart:"NOCHART", rc->name);
						}
					}
					else if (unlikely(rc->rrdcalc_flags & RRDCALC_FLAG_DB_STALE))
						rc->rrdcalc_flags &= ~RRDCALC_FLAG_DB_STALE;
					*/

					if (unlikely(value_is_null)) {
						// collected value is null
						rc->value = NAN;
						rc->rrdcalc_flags |= RRDCALC_FLAG_DB_NAN;

						debug(D_HEALTH,
							  "Health on host '%s', alarm '%s.%s': database lookup returned empty value (possibly value is not collected yet)",
							  host->hostname, rc->chart ? rc->chart : "NOCHART", rc->name
						);
					} else
						rc->rrdcalc_flags &= ~RRDCALC_FLAG_DB_NAN;

					debug(D_HEALTH, "Health on host '%s', alarm '%s.%s': database lookup gave value "
							CALCULATED_NUMBER_FORMAT, host->hostname, rc->chart ? rc->chart : "NOCHART", rc->name,
						  rc->value
					);
				}

				// ------------------------------------------------------------
				// if there is calculation expression, run it

				if (unlikely(rc->calculation)) {
					if (unlikely(!expression_evaluate(rc->calculation))) {
						// calculation failed
						rc->value = NAN;
						rc->rrdcalc_flags |= RRDCALC_FLAG_CALC_ERROR;

						debug(D_HEALTH, "Health on host '%s', alarm '%s.%s': expression '%s' failed: %s",
							  host->hostname, rc->chart ? rc->chart : "NOCHART", rc->name,
							  rc->calculation->parsed_as, buffer_tostring(rc->calculation->error_msg)
						);
					} else {
						rc->rrdcalc_flags &= ~RRDCALC_FLAG_CALC_ERROR;

						debug(D_HEALTH, "Health on host '%s', alarm '%s.%s': expression '%s' gave value "
								CALCULATED_NUMBER_FORMAT
								": %s (source: %s)", host->hostname, rc->chart ? rc->chart : "NOCHART", rc->name,
							  rc->calculation->parsed_as, rc->calculation->result,
							  buffer_tostring(rc->calculation->error_msg), rc->source
						);

						rc->value = rc->calculation->result;

						if (rc->local) rc->local->last_updated = now;
						if (rc->family) rc->family->last_updated = now;
						if (rc->hostid) rc->hostid->last_updated = now;
						if (rc->hostname) rc->hostname->last_updated = now;
					}
				}
			}

			rrdhost_unlock(host);

			if (unlikely(runnable && !netdata_exit)) {
				rrdhost_rdlock(host);

				for (rc = host->alarms; rc; rc = rc->next) {
					if (unlikely(!(rc->rrdcalc_flags & RRDCALC_FLAG_RUNNABLE)))
						continue;

					if (rc->rrdcalc_flags & RRDCALC_FLAG_DISABLED) {
						continue;
					}
					RRDCALC_STATUS warning_status = RRDCALC_STATUS_UNDEFINED;
					RRDCALC_STATUS critical_status = RRDCALC_STATUS_UNDEFINED;

					// --------------------------------------------------------
					// check the warning expression

					if (likely(rc->warning)) {
						if (unlikely(!expression_evaluate(rc->warning))) {
							// calculation failed
							rc->rrdcalc_flags |= RRDCALC_FLAG_WARN_ERROR;

							debug(D_HEALTH,
								  "Health on host '%s', alarm '%s.%s': warning expression failed with error: %s",
								  host->hostname, rc->chart ? rc->chart : "NOCHART", rc->name,
								  buffer_tostring(rc->warning->error_msg)
							);
						} else {
							rc->rrdcalc_flags &= ~RRDCALC_FLAG_WARN_ERROR;
							debug(D_HEALTH, "Health on host '%s', alarm '%s.%s': warning expression gave value "
									CALCULATED_NUMBER_FORMAT
									": %s (source: %s)", host->hostname, rc->chart ? rc->chart : "NOCHART",
								  rc->name, rc->warning->result, buffer_tostring(rc->warning->error_msg), rc->source
							);
							warning_status = rrdcalc_value2status(rc->warning->result);
						}
					}

					// --------------------------------------------------------
					// check the critical expression

					if (likely(rc->critical)) {
						if (unlikely(!expression_evaluate(rc->critical))) {
							// calculation failed
							rc->rrdcalc_flags |= RRDCALC_FLAG_CRIT_ERROR;

							debug(D_HEALTH,
								  "Health on host '%s', alarm '%s.%s': critical expression failed with error: %s",
								  host->hostname, rc->chart ? rc->chart : "NOCHART", rc->name,
								  buffer_tostring(rc->critical->error_msg)
							);
						} else {
							rc->rrdcalc_flags &= ~RRDCALC_FLAG_CRIT_ERROR;
							debug(D_HEALTH, "Health on host '%s', alarm '%s.%s': critical expression gave value "
									CALCULATED_NUMBER_FORMAT
									": %s (source: %s)", host->hostname, rc->chart ? rc->chart : "NOCHART",
								  rc->name, rc->critical->result, buffer_tostring(rc->critical->error_msg),
								  rc->source
							);
							critical_status = rrdcalc_value2status(rc->critical->result);
						}
					}

					// --------------------------------------------------------
					// decide the final alarm status

					RRDCALC_STATUS status = RRDCALC_STATUS_UNDEFINED;

					switch (warning_status) {
						case RRDCALC_STATUS_CLEAR:
							status = RRDCALC_STATUS_CLEAR;
							break;

						case RRDCALC_STATUS_RAISED:
							status = RRDCALC_STATUS_WARNING;
							break;

						default:
							break;
					}

					switch (critical_status) {
						case RRDCALC_STATUS_CLEAR:
							if (status == RRDCALC_STATUS_UNDEFINED)
								status = RRDCALC_STATUS_CLEAR;
							break;

						case RRDCALC_STATUS_RAISED:
							status = RRDCALC_STATUS_CRITICAL;
							break;

						default:
							break;
					}

					// --------------------------------------------------------
					// check if the new status and the old differ

					if (status != rc->status) {
						int delay = 0;

						// apply trigger hysteresis

						if (now > rc->delay_up_to_timestamp) {
							rc->delay_up_current = rc->delay_up_duration;
							rc->delay_down_current = rc->delay_down_duration;
							rc->delay_last = 0;
							rc->delay_up_to_timestamp = 0;
						} else {
							rc->delay_up_current = (int) (rc->delay_up_current * rc->delay_multiplier);
							if (rc->delay_up_current > rc->delay_max_duration)
								rc->delay_up_current = rc->delay_max_duration;

							rc->delay_down_current = (int) (rc->delay_down_current * rc->delay_multiplier);
							if (rc->delay_down_current > rc->delay_max_duration)
								rc->delay_down_current = rc->delay_max_duration;
						}

						if (status > rc->status)
							delay = rc->delay_up_current;
						else
							delay = rc->delay_down_current;

						// COMMENTED: because we do need to send raising alarms
						// if(now + delay < rc->delay_up_to_timestamp)
						//    delay = (int)(rc->delay_up_to_timestamp - now);

						rc->delay_last = delay;
						rc->delay_up_to_timestamp = now + delay;

						health_alarm_log(
								host, rc->id, rc->next_event_id++, now, rc->name, rc->rrdset->id,
								rc->rrdset->family, rc->exec, rc->recipient, now - rc->last_status_change,
								rc->old_value, rc->value, rc->status, status, rc->source, rc->units, rc->info,
								rc->delay_last,
								(
								    ((rc->options & RRDCALC_FLAG_NO_CLEAR_NOTIFICATION)? HEALTH_ENTRY_FLAG_NO_CLEAR_NOTIFICATION : 0) |
								    ((rc->rrdcalc_flags & RRDCALC_FLAG_SILENCED)? HEALTH_ENTRY_FLAG_SILENCED : 0)
								)

						);

						rc->last_status_change = now;
						rc->status = status;
					}

					rc->last_updated = now;
					rc->next_update = now + rc->update_every;

					if (next_run > rc->next_update)
						next_run = rc->next_update;
				}

				rrdhost_unlock(host);
			}

			if (unlikely(netdata_exit))
				break;

			// execute notifications
			// and cleanup
			health_alarm_log_process(host);

			if (unlikely(netdata_exit))
				break;

		} /* rrdhost_foreach */

		rrd_unlock();


        if(unlikely(netdata_exit))
            break;

        now = now_realtime_sec();
        if(now < next_run) {
            debug(D_HEALTH, "Health monitoring iteration no %u done. Next iteration in %d secs", loop, (int) (next_run - now));
            sleep_usec(USEC_PER_SEC * (usec_t) (next_run - now));
            now = now_realtime_sec();
        }
        else
            debug(D_HEALTH, "Health monitoring iteration no %u done. Next iteration now", loop);

    } // forever

    netdata_thread_cleanup_pop(1);
    return NULL;
}