expr value

  - name: prom-TSDB-head-WAL-trunc-fail
    rules:
      - alert: TSDB WAL truncations failed
        expr: |
          label_replace(
           increase(prometheus_tsdb_wal_truncations_failed_total[10m]) > 0,
           "ipaddr",
           "$1",
           "instance",
           "([^:]+):.*"
          ) * on(ipaddr) group_left(nodename, domainname)
          label_replace(
           node_uname_info,
           "ipaddr",
           "$1",
           "instance",
           "([^:]+):.*"
          )
        for: 5m
        labels:
          type: prom
          opsgprio: P1
          severity: critical
          alertsub0: "{{$labels.nodename}}"
        annotations:
          summary: "{{$labels.nodename}}: TSDB WAL truncations failed"
          description: "Prometheus encountered [{{$value}}] TSDB WAL truncation failures."