[distro-setup] / filesystem / etc / prometheus / rules / iank.yml

# 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'


  # 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="kdwg:9101"} <= 60 * 17
    labels:
      severity: warn

  - alert: 1pmtest
    expr: hour() == 17 and minute() < 5
    for: 0m
    labels:
      severity: daytest
    annotations:
      summary: Prometheus daily 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"} == 0
    for: 30m
    labels:
      severity: warn
    annotations:
      summary: Target down for 30m

  - 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


# note, the next upstream metric is intentionally omitted:
# https://github.com/samber/awesome-prometheus-alerts/issues/283

  - 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 }}"