ansible/roles/prometheus/templates/postgres.rules.yml.j2

---
{{ ansible_managed | comment }}

{% macro raw(string) -%}
{{ "{{" }} {{ string }} {{ "}}" }}
{%- endmacro %}

groups:

  - name: postgres.rules
    rules:
      - alert: PostgresqlDown
        expr: pg_up == 0
        for: 0m
        labels:
          severity: critical
        annotations:
          summary: Serveur PostgreSQL down

      - alert: PostgresqlRestarted
        expr: time() - pg_postmaster_start_time_seconds < 60
        for: 0m
        labels:
          severity: critical
        annotations:
          summary: Serveur PostgreSQL redémarré

      - alert: PostgresqlExporterError
        expr: pg_exporter_last_scrape_error > 0
        for: 0m
        labels:
          severity: critical
        annotations:
          summary: Erreur dans l'exporter PostgreSQL

      - alert: PostgresqlReplicationLag
        expr:
          pg_replication_lag > 30
          and
          ON(instance) pg_replication_is_replica == 1
        for: 0m
        labels:
          severity: critical
        annotations:
          summary: >-
            La réplication PostgreSQL lag ({{ raw('$value') }} > 30s)
            (base de données {{ raw('$labels.datname') }} )

      - alert: PostgresqlTableNotVaccumed
        expr:
          time() - pg_stat_user_tables_last_autovacuum
          > 60 * 60 * 24
        for: 0m
        labels:
          severity: warning
        annotations:
          summary: >-
            Le démon autovacuum n'a pas été lancé depuis 24h
            (base de données {{ raw('$labels.datname') }} )

      - alert: PostgresqlTableNotAnalyzed
        expr:
          time() - pg_stat_user_tables_last_autoanalyze
          > 60 * 60 * 24
        for: 0m
        labels:
          severity: warning
        annotations:
          summary: >-
            Table non-analysée depuis 24h
            (base de données {{ raw('$labels.datname') }})

      - alert: PostgresqlTooManyConnections
        expr:
          (
            sum by (datname)
              (pg_stat_activity_count{datname!~"template.*|postgres"})
          ) * 100
          > pg_settings_max_connections * 80
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: >-
            PostgreSQL a trop de connexions
            ({{ raw('$value | printf "%.1f"') }} > 80%)
            (base de données {{ raw('$labels.datname') }})

      - alert: PostgresqlDeadLocks
        expr: increase(pg_stat_database_deadlocks{datname!~"template.*|postgres"}[1m]) > 5
        for: 0m
        labels:
          severity: warning
        annotations:
          summary: >-
            PostgreSQL a plus de 5 deadlocks.
            (base de données {{ raw('$labels.datname') }} )

      - alert: PostgresqlSlowQueries
        expr: pg_slow_queries > 0
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: >-
            Présence de requêtes lentes (slow-queries)
            (base de données {{ raw('$labels.datname') }} )

      - alert: PostgresqlHighRollbackRate
        expr:
          (
            rate(pg_stat_database_xact_rollback{datname!~"template.*"}[3m]) /
            rate(pg_stat_database_xact_commit{datname!~"template.*"}[3m])
          ) * 100 
          > 20
        for: 0m
        labels:
          severity: warning
        annotations:
          summary: >-
            PostgreSQL a un taux de retour en arrière (rollback) élevé
            (base de données {{ raw('$labels.datname') }}, valeur {{ raw('$value | printf "%.1f"') }} %)

      - alert: PostgresqlWaleReplicationStopped
        expr: rate(pg_xlog_position_bytes[1m]) == 0
        for: 0m
        labels:
          severity: critical
        annotations:
          summary: >-
            Réplication de PostgreSQL WALE stoppée
            (base de données {{ raw('$labels.datname') }} )

      - alert: PostgresqlHighRateStatementTimeout
        expr: rate(postgresql_errors_total{type="statement_timeout"}[1m]) > 3
        for: 0m
        labels:
          severity: critical
        annotations:
          summary: >-
            Beaucoup de requêtes PostgreSQL sont timeout
            (base de données {{ raw('$labels.datname') }}, valeur {{ raw('$value | printf "%.1f"') }} )

      - alert: PostgresqlHighRateDeadlock
        expr: increase(postgresql_errors_total{type="deadlock_detected"}[1m]) > 1
        for: 0m
        labels:
          severity: critical
        annotations:
          summary: >-
            PostgreSQL a un fort taux de deadlock
            (base de données {{ raw('$labels.datname') }}, valeur {{ raw('$value | printf "%.1f"') }} )

#      - alert: PostgresqlReplicationLagBytes
#        expr:
#          (pg_xlog_position_bytes and pg_replication_is_replica == 0)
#          - GROUP_RIGHT(instance) (pg_xlog_position_bytes and pg_replication_is_replica == 1)
#          > 1e+09
#        for: 0m
#        labels:
#          severity: critical
#        annotations:
#          summary: La réplication Postgresql a des octets de retard (instance {{ raw('$labels.name') }}, value {{ raw('$value') }} )

      - alert: PostgresqlTooManyDeadTuples
        expr:
          (
            (pg_stat_user_tables_n_dead_tup > 10000)
            / (pg_stat_user_tables_n_live_tup + pg_stat_user_tables_n_dead_tup)
          ) >= 0.1 unless ON(instance) (pg_replication_is_replica == 1)
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: >-
            Les tuples morts PostgreSQL sont trop volumineux
            (base de données {{ raw('$labels.datname') }}, valeur {{ raw('$value | printf "%.1f"') }} )

      - alert: PostgresqlSplitBrain
        expr: count(pg_replication_is_replica == 0) != 1
        for: 0m
        labels:
          severity: critical
        annotations:
          summary: >-
            Split Brain : trop de bases de données PostgreSQL primaires en mode lecture-écriture
            (base de données {{ raw('$labels.datname') }}, valeur {{ raw('$value') }} )

      - alert: PostgresqlPromotedNode
        expr:
          pg_replication_is_replica
          and
          changes(pg_replication_is_replica[1m]) > 0
        for: 0m
        labels:
          severity: warning
        annotations:
          summary: >-
            Le serveur de secours PostgreSQL a été promu comme nœud principal
            (base de données {{ raw('$labels.datname') }}, valeur {{ raw('$value') }})

      - alert: PostgresqlTooManyLocksAcquired
        expr:
          (
            (sum (pg_locks_count))
            / (pg_settings_max_locks_per_transaction * pg_settings_max_connections)
          ) * 100 > 20
        for: 2m
        labels:
          severity: critical
        annotations:
          summary: >-
            Trop de deadlocks acquis sur la base de données.
            Si cette alerte se produit fréquemment, nous devrons peut-être augmenter
            le paramètre postgres max_locks_per_transaction
            (Valeur = {{ raw('$value | printf "%.1f"') }} )

...