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:
            description: |-
                Node memory is filling up (< 10% left)
                  VALUE = {{ $value }}
                  LABELS = {{ $labels }}
            summary: Host out of memory (instance {{ $labels.instance }})
        - alert: HostMemoryUnderMemoryPressure
          expr: (rate(node_vmstat_pgmajfault[1m]) > 1000) * on (instance) group_left (nodename) node_uname_info{nodename=~".+"}
          for: 2m
          labels:
            severity: warning
          annotations:
            description: |-
                The node is under heavy memory pressure. High rate of major page faults
                  VALUE = {{ $value }}
                  LABELS = {{ $labels }}
            summary: Host memory under memory pressure (instance {{ $labels.instance }})
        - 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:
            description: |-
                Node memory is < 20% for 1 week. Consider reducing memory space. (instance {{ $labels.instance }})
                  VALUE = {{ $value }}
                  LABELS = {{ $labels }}
            summary: Host Memory is underutilized (instance {{ $labels.instance }})
        - 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:
            description: |-
                Disk is almost full (< 10% left)
                  VALUE = {{ $value }}
                  LABELS = {{ $labels }}
            summary: Host out of disk space (instance {{ $labels.instance }})
        - 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:
            description: |-
                Filesystem is predicted to run out of space within the next 24 hours at current write rate
                  VALUE = {{ $value }}
                  LABELS = {{ $labels }}
            summary: Host disk will fill in 24 hours (instance {{ $labels.instance }})
        - 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:
            description: |-
                CPU load is < 20% for 1 week. Consider reducing the number of CPUs.
                  VALUE = {{ $value }}
                  LABELS = {{ $labels }}
            summary: Host CPU is underutilized (instance {{ $labels.instance }})
        - 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=~".+"}
          labels:
            severity: warning
          annotations:
            description: |-
                CPU steal is > 10%. A noisy neighbor is killing VM performances or a spot instance may be out of credit.
                  VALUE = {{ $value }}
                  LABELS = {{ $labels }}
            summary: Host CPU steal noisy neighbor (instance {{ $labels.instance }})
        - alert: HostOomKillDetected
          expr: (increase(node_vmstat_oom_kill[1m]) > 0) * on (instance) group_left (nodename) node_uname_info{nodename=~".+"}
          labels:
            severity: warning
          annotations:
            description: |-
                OOM kill detected
                  VALUE = {{ $value }}
                  LABELS = {{ $labels }}
            summary: Host OOM kill detected (instance {{ $labels.instance }})
        - 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:
            description: |-
                The network interface "{{ $labels.device }}" on "{{ $labels.instance }}" is getting overloaded.
                  VALUE = {{ $value }}
                  LABELS = {{ $labels }}
            summary: Host Network Interface Saturated (instance {{ $labels.instance }})