# other rules to consider: # filesystem, network, ntp rules: # https://github.com/cloudalchemy/ansible-prometheus defaults/main.yml # on my system, the interpolated values are in /a/opt/ansible-prometheus/rules.yml # groups: - name: standard rules: # ## uncomment for testing an alert firing # - alert: test-alert4 # expr: vector(1) # for: 0m # labels: # severity: day # annotations: # description: "always-firing alert VALUE = {{ $value }}" ###### BEGIN MISC NOTES ###### # # other interesting exporters # https://github.com/prometheus-community/node-exporter-textfile-collector-scripts # # interesting post: https://www.metricfire.com/blog/top-5-prometheus-alertmanager-gotchas/ # interesting promql query that could be useful later. # changes(ALERTS_FOR_STATE[24h]) # # # # alert flap strategy. # https://roidelapluie.be/blog/2019/02/21/prometheus-last/ # # Another idea generally is to make an alert that fires for 24 hours and # inhibits another alert for the same thing, which we want at most # 1 alert per 24 hours. ###### END MISC NOTES ###### # various queries only look at increases, so invert the up metric so we # can better query on down. - record: down expr: up == bool 0 # convenience metric to use in multiple alert expressions - record: mailtest_lag_inhibit expr: present_over_time(ALERTS{alertname=~"kd_eth0_down|target_down|cmc_wan_down"}[17m]) or on() count_over_time(up{job="prometheus"}[19m]) <= 18 # the node_network_info here goes away when it is down, # https://www.robustperception.io/absent-alerting-for-scraped-metrics # # What this says is: return metric if up == 1 if there isnt also # the right hand metric (with the same instance+job). # # aka: # ! exists(operstate=up) && up - alert: cmc_wan_down expr: |- up{instance="10.2.0.1:9100"} == 1 unless on(instance,job) node_network_info{instance="10.2.0.1:9100",device="wan",operstate="up"} labels: severity: day - alert: kd_eth0_down expr: |- node_network_up{instance="kdwg:9101",device="eth0"} != 1 labels: severity: day # alerting on missing metrics: # https://www.robustperception.io/absent-alerting-for-scraped-metrics # that doesnt work if we want to alert across multiple hosts, eg # up{job="node"} == 1 unless node_systemd_unit_state{name="systemstatus.service",state="active",job="node"} # however, google lead me to a solution here # https://www.linkedin.com/pulse/prometheus-alert-missing-metrics-labels-nirav-shah # there is also the absent() function, but i didnt see a way to make that work - alert: mysers_units_missing expr: |- count(up{job="node"} == 1) by (instance) * 3 unless count(node_systemd_unit_state{name=~"(systemstatus|btrfsmaintstop|dynamicipupdate).service",state="active"}) by (instance) for: 20m labels: severity: warn - alert: epanicclean_not_active expr: |- node_systemd_unit_state{name="epanicclean.service",state="active"} != 1 for: 20m labels: severity: warn - alert: epanicclean_missing expr: |- count(up{job=~"node|tlsnode"} == 1) by (instance) unless count(node_systemd_unit_state{job=~"node|tlsnode",name="epanicclean.service",state="active"}) by (instance) for: 20m labels: severity: warn - alert: mysers_not_active expr: |- node_systemd_unit_state{name=~"(systemstatus|btrfsmaintstop|dynamicipupdate).service",state="active"} != 1 for: 20m labels: severity: warn # todo: at some point, look into making mailtest-check either be resilient to the internet going down, # or inhibit or group this alert with it going down. - alert: sysd_result_fail # not sure 30m is really needed, it prevents the alert from flapping # i guess. expr: |- rate(node_systemd_unit_result_fail_count[30m]) > 0 labels: severity: day - alert: exim_paniclog expr: |- exim_paniclog > 0 labels: severity: day - alert: check_crypttab expr: |- check_crypttab > 0 labels: severity: prod # 17 minutes: We try to send every 5 minutes. if we reboot causing 1 # send to fail, thats 10 minutes between 2 sends. we test this every 5 # minutes, so thats 15 minutes of time we can expect for 1 failed email, # and 1 failed email is expected due to reboots or other tiny issues we # dont care about. # # cmc_wan_down etc, inhibits other alerts, but mailtest_check needs # additional time to recover after an outage. We can only inhibit while # an alert is actually firing, it doesnt affect the "for:" # condition. So, we have those alerts that need to be delayed be # conditioned on a query for that alert having not been firing in the # last X minutes. However, there is a special case when prometheus # itself was down, and so there was no alert. So, I test for missing # of metric that gets generated for prometheus itself. If for some # reason that has a problem, I could make it more conservative by # checking that we booted recently instead, eg: # time() - node_boot_time_seconds{instance="kdwg:9101"} <= 60 * 17 - alert: mailtest_check_vps expr: |- time() - mailtest_check_last_usec{job="tlsnode"} >= 60 * 17 unless on() mailtest_lag_inhibit labels: severity: day annotations: summary: '17 minutes down' - alert: mailtest_check_mailhost expr: |- time() - max by (folder,from) (mailtest_check_last_usec{job="node"}) >= 60 * 17 unless on() mailtest_lag_inhibit labels: severity: day annotations: summary: '17 minutes down' # 20 minutes. just allow for more due to prod alert. - alert: mailtest_check_gnu_mailhost expr: |- time() - max by (folder,from) (mailtest_check_last_usec{folder="/m/md/l/testignore", from="iank@gnu.org"}) >= 60 * 20 unless on() mailtest_lag_inhibit labels: severity: prod annotations: summary: '20 minutes down' - alert: mailtest_check_unexpected_spamd_vps expr: |- mailtest_check_unexpected_spamd_results >= 1 labels: severity: day annotations: summary: 'jr -u mailtest-check -e -n 10000' - alert: mailtest_check_missing_dnswl expr: |- mailtest_check_missing_dnswl >= 1 for: 30m labels: severity: day annotations: summary: 'jr -u mailtest-check -e -n 10000' # We expect to be getting metrics, if we come up and notice we have # any missing in the past, and it wasn't from a reboot, and we haven't # fired any other alerts, make an alert. In testing, the the count is # 19 for 19 minutes, but I make it 18 just to give a bit of slack. - alert: historical_missing_metric expr: |- count_over_time(up{job="prometheus"}[19m]) <= 18 unless on() present_over_time(ALERTS[19m]) unless on() time() - node_boot_time_seconds{instance="kd"} <= 60 * 17 labels: severity: warn # 10 am friday. but, do it 1 minute early so it is closer to actually # firing at 10 am. - alert: dead_man_test expr: |- ( hour() == 13 and minute() >= 59 or hour() == 14 and minute() < 3 ) and day_of_week() == 5 for: 0m labels: severity: daytest annotations: summary: Prometheus weekly test alert #### Inhibit notes #### ## Example of expressions to detect if the target_down alert # fired in the last 24 hours. Initially, I thought his could # be an alert which inhibits up_resets, but eventually I figured # that doesn't make much sense, and the idea of using an alert # that is not an indication of something wrong, only inhibits another # alert, I think works better to integrate directly into the # alert it would inhibit, this may mean a recording rule. That avoids # an alert we have to ignore or filter out. # # Alternate expression, to calculate if the alert would have fired is: # min_over_time(sum_over_time(up[30m])[1d:]) == 0 # where 30m matches the for: time in target_down # # Note: for graphing, surround in the expression in sum_over_time() # ALERTS{alertname="target_down",alertstate="firing"}[1d] #### end Inhibit notes #### # For targets where we alert only on long downtimes, we # still want to know if it is going down many times for short times over # a long period of time. But ignore reboots. # ## Another way would be to detect an overall downtime: # avg_over_time(node_systemd_unit_state{name="dynamicipupdate.service",state="active"}[1d]) < .95 # However, this seems to just find too many false positives for now, so # commenting it out. # - alert: up_resets # expr: |- # resets(up[1d]) - changes(node_boot_time_seconds[1d]) > 12 # labels: # severity: warn # annotations: # summary: "Target has gone down {{ $value }} times in 1 day, > 12" # https://awesome-prometheus-alerts.grep.to/rules # todo, we should probably group the prometheus alerts that indicate a # host-local problem. # eg, set a label alert-group: local-prom, then make a receiver that # groups by it when the alert-group is local-prom. - name: awesome prometheus alerts rules: - alert: PrometheusJobMissing expr: absent(up{job="prometheus"}) for: 30m labels: severity: day annotations: summary: Prometheus job missing (instance {{ $labels.instance }}) description: "A Prometheus job has disappeared\n VALUE = {{ $value }}" - alert: lowpri_target_down expr: up{instance!~"kdwg:9101|bkex.b8.nz:9101|liex.b8.nz:9101|10.2.0.1:9100|kwwg:9101"} == 0 for: 30m labels: severity: warn annotations: summary: Target down for 30m # note PrometheusAllTargetsMissing is intentionally omitted because it # is redundant to the above. - alert: target_down expr: up{instance=~"kdwg:9101|bkex.b8.nz:9101|liex.b8.nz:9101|10.2.0.1:9100"} == 0 for: 5m labels: severity: day annotations: summary: High priority target down for 5m - alert: target_down expr: absent(present_over_time(mailtest_check_last_usec{folder="/m/md/l/testignore",from="ian@iankelling.org"}[5m])) for: 5m labels: severity: day annotations: summary: MAIL_HOST likely down for 5m - alert: PrometheusConfigurationReloadFailure expr: prometheus_config_last_reload_successful != 1 for: 30m labels: severity: day annotations: description: "Prometheus configuration reload error\n VALUE = {{ $value }}" - alert: PrometheusTooManyRestarts expr: changes(process_start_time_seconds{job=~"prometheus|pushgateway|alertmanager"}[30m]) > 10 for: 0m labels: severity: warning annotations: description: "Prometheus has restarted more than ten times in the last 30 minutes. It might be crashlooping.\n VALUE = {{ $value }}" - alert: PrometheusAlertmanagerJobMissing expr: absent(up{job="alertmanager"}) for: 30m labels: severity: warn annotations: description: "A Prometheus AlertManager job has disappeared\n VALUE = {{ $value }}" - alert: PrometheusAlertmanagerConfigurationReloadFailure expr: alertmanager_config_last_reload_successful != 1 for: 30m labels: severity: day annotations: description: "AlertManager configuration reload error\n VALUE = {{ $value }}" - alert: PrometheusNotConnectedToAlertmanager expr: prometheus_notifications_alertmanagers_discovered < 1 for: 30m labels: severity: day annotations: description: "Prometheus cannot connect the alertmanager\n VALUE = {{ $value }}" - alert: PrometheusRuleEvaluationFailures expr: increase(prometheus_rule_evaluation_failures_total[3m]) > 0 for: 30m labels: severity: warn annotations: description: "Prometheus encountered {{ $value }} rule evaluation failures, leading to potentially ignored alerts.\n VALUE = {{ $value }}" - alert: PrometheusTemplateTextExpansionFailures expr: increase(prometheus_template_text_expansion_failures_total[3m]) > 0 for: 30m labels: severity: warn annotations: description: "Prometheus encountered {{ $value }} template text expansion failures\n VALUE = {{ $value }}" - alert: PrometheusRuleEvaluationSlow expr: prometheus_rule_group_last_duration_seconds > prometheus_rule_group_interval_seconds for: 5m labels: severity: warn annotations: description: "Prometheus rule evaluation took more time than the scheduled interval. It indicates a slower storage backend access or too complex query.\n VALUE = {{ $value }}" - alert: PrometheusNotificationsBacklog expr: min_over_time(prometheus_notifications_queue_length[30m]) > 0 for: 0m labels: severity: warn annotations: description: "The Prometheus notification queue has not been empty for 10 minutes\n VALUE = {{ $value }}" - alert: PrometheusAlertmanagerNotificationFailing expr: rate(alertmanager_notifications_failed_total[1m]) > 0 for: 30m labels: severity: warn annotations: description: "Alertmanager is failing sending notifications\n VALUE = {{ $value }}" # file_sd doesnt count as service discovery, so 0 is expected. # - alert: PrometheusTargetEmpty # expr: prometheus_sd_discovered_targets == 0 # for: 30m # labels: # severity: day # annotations: # description: "Prometheus has no target in service discovery\n VALUE = {{ $value }}" - alert: PrometheusTargetScrapingSlow expr: prometheus_target_interval_length_seconds{quantile="0.9"} > 90 for: 30m labels: severity: warn annotations: description: "Prometheus is scraping exporters slowly\n VALUE = {{ $value }}" - alert: PrometheusLargeScrape expr: increase(prometheus_target_scrapes_exceeded_sample_limit_total[10m]) > 10 for: 30m labels: severity: warn annotations: description: "Prometheus has many scrapes that exceed the sample limit\n VALUE = {{ $value }}" - alert: PrometheusTargetScrapeDuplicate expr: increase(prometheus_target_scrapes_sample_duplicate_timestamp_total[5m]) > 0 for: 30m labels: severity: warn annotations: description: "Prometheus has many samples rejected due to duplicate timestamps but different values\n VALUE = {{ $value }}" - alert: PrometheusTsdbCheckpointCreationFailures expr: increase(prometheus_tsdb_checkpoint_creations_failed_total[1m]) > 0 for: 30m labels: severity: warn annotations: description: "Prometheus encountered {{ $value }} checkpoint creation failures\n VALUE = {{ $value }}" - alert: PrometheusTsdbCheckpointDeletionFailures expr: increase(prometheus_tsdb_checkpoint_deletions_failed_total[1m]) > 0 for: 30m labels: severity: warn annotations: description: "Prometheus encountered {{ $value }} checkpoint deletion failures\n VALUE = {{ $value }}" - alert: PrometheusTsdbCompactionsFailed expr: increase(prometheus_tsdb_compactions_failed_total[1m]) > 0 for: 30m labels: severity: warn annotations: description: "Prometheus encountered {{ $value }} TSDB compactions failures\n VALUE = {{ $value }}" - alert: PrometheusTsdbHeadTruncationsFailed expr: increase(prometheus_tsdb_head_truncations_failed_total[1m]) > 0 for: 30m labels: severity: warn annotations: description: "Prometheus encountered {{ $value }} TSDB head truncation failures\n VALUE = {{ $value }}" - alert: PrometheusTsdbReloadFailures expr: increase(prometheus_tsdb_reloads_failures_total[1m]) > 0 for: 30m labels: severity: warn annotations: description: "Prometheus encountered {{ $value }} TSDB reload failures\n VALUE = {{ $value }}" - alert: PrometheusTsdbWalCorruptions expr: increase(prometheus_tsdb_wal_corruptions_total[1m]) > 0 for: 30m labels: severity: warn annotations: description: "Prometheus encountered {{ $value }} TSDB WAL corruptions\n VALUE = {{ $value }}" - alert: PrometheusTsdbWalTruncationsFailed expr: increase(prometheus_tsdb_wal_truncations_failed_total[1m]) > 0 for: 30m labels: severity: warn annotations: description: "Prometheus encountered {{ $value }} TSDB WAL truncation failures\n VALUE = {{ $value }}"