groups:
  - name: Host & hardware
    rules:
      - alert: HostOutOfMemory
        expr: (node_memory_MemAvailable_bytes / node_memory_MemTotal_bytes * 100 < 10) * on(instance) group_left (nodename) node_uname_info{nodename=~".+"}
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: Host out of memory (instance {{ $labels.instance }})
          description: "Node memory is filling up (< 10% left)\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
      - alert: HostMemoryUnderMemoryPressure
        expr: (rate(node_vmstat_pgmajfault[1m]) > 1000) * on(instance) group_left (nodename) node_uname_info{nodename=~".+"}
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: Host memory under memory pressure (instance {{ $labels.instance }})
          description: "The node is under heavy memory pressure. High rate of major page faults\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
      - alert: HostMemoryIsUnderutilized
        expr: (100 - (avg_over_time(node_memory_MemAvailable_bytes[30m]) / node_memory_MemTotal_bytes * 100) < 20) * on(instance) group_left (nodename) node_uname_info{nodename=~".+"}
        for: 1w
        labels:
          severity: info
        annotations:
          summary: Host Memory is underutilized (instance {{ $labels.instance }})
          description: "Node memory is < 20% for 1 week. Consider reducing memory space. (instance {{ $labels.instance }})\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
      - alert: HostOutOfDiskSpace
        expr: ((node_filesystem_avail_bytes * 100) / node_filesystem_size_bytes < 10 and ON (instance, device, mountpoint) node_filesystem_readonly == 0) * on(instance) group_left (nodename) node_uname_info{nodename=~".+"}
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: Host out of disk space (instance {{ $labels.instance }})
          description: "Disk is almost full (< 10% left)\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
      - alert: HostDiskWillFillIn24Hours
        expr: ((node_filesystem_avail_bytes * 100) / node_filesystem_size_bytes < 10 and ON (instance, device, mountpoint) predict_linear(node_filesystem_avail_bytes{fstype!~"tmpfs"}[1h], 24 * 3600) < 0 and ON (instance, device, mountpoint) node_filesystem_readonly == 0) * on(instance) group_left (nodename) node_uname_info{nodename=~".+"}
        for: 2m
        labels:
          severity: warning
        annotations:
          summary: Host disk will fill in 24 hours (instance {{ $labels.instance }})
          description: "Filesystem is predicted to run out of space within the next 24 hours at current write rate\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
      - alert: HostCpuIsUnderutilized
        expr: (100 - (rate(node_cpu_seconds_total{mode="idle"}[30m]) * 100) < 20) * on(instance) group_left (nodename) node_uname_info{nodename=~".+"}
        for: 1w
        labels:
          severity: info
        annotations:
          summary: Host CPU is underutilized (instance {{ $labels.instance }})
          description: "CPU load is < 20% for 1 week. Consider reducing the number of CPUs.\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
      - alert: HostCpuStealNoisyNeighbor
        expr: (avg by(instance) (rate(node_cpu_seconds_total{mode="steal"}[5m])) * 100 > 10) * on(instance) group_left (nodename) node_uname_info{nodename=~".+"}
        for: 0m
        labels:
          severity: warning
        annotations:
          summary: Host CPU steal noisy neighbor (instance {{ $labels.instance }})
          description: "CPU steal is > 10%. A noisy neighbor is killing VM performances or a spot instance may be out of credit.\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
      - alert: HostOomKillDetected
        expr: (increase(node_vmstat_oom_kill[1m]) > 0) * on(instance) group_left (nodename) node_uname_info{nodename=~".+"}
        for: 0m
        labels:
          severity: warning
        annotations:
          summary: Host OOM kill detected (instance {{ $labels.instance }})
          description: "OOM kill detected\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"
      - alert: HostNetworkInterfaceSaturated
        expr: ((rate(node_network_receive_bytes_total{device!~"^tap.*|^vnet.*|^veth.*|^tun.*"}[1m]) + rate(node_network_transmit_bytes_total{device!~"^tap.*|^vnet.*|^veth.*|^tun.*"}[1m])) / node_network_speed_bytes{device!~"^tap.*|^vnet.*|^veth.*|^tun.*"} > 0.8 < 10000) * on(instance) group_left (nodename) node_uname_info{nodename=~".+"}
        for: 1m
        labels:
          severity: warning
        annotations:
          summary: Host Network Interface Saturated (instance {{ $labels.instance }})
          description: "The network interface \"{{ $labels.device }}\" on \"{{ $labels.instance }}\" is getting overloaded.\n  VALUE = {{ $value }}\n  LABELS = {{ $labels }}"