Disk_used_percent is missing for iscsi disks

Telegraf
1

I can’t get telegraf to include disk_used_percent for iscsi disks. The metrics for the mount point “/” are properly delivered. But the metrics for “/var/lib/docker/volumes” and “/usr/local/backup” are missing. The docker image used is the most recent available. The filesystem used on the disks is ext4. Any ideas what I forgot?

compose.yml

  telegraf:
    container_name: grafana-telegraf
    image: telegraf:alpine
    user: telegraf:989
    pid: host
    network_mode: host
    restart: unless-stopped
    depends_on:
      - prometheus
    volumes:
      - ./telegraf.conf:/etc/telegraf/telegraf.conf:ro
#      - /var/run/docker.sock:/var/run/docker.sock:ro
      - /var/run:/var/run:ro
      - /proc/net:/hostfs/proc/net:ro
      - /dev:/dev:ro

telegraf.conf


[agent]
  interval = "15s"
  round_interval = true
  metric_batch_size = 1000
  metric_buffer_limit = 10000
  collection_jitter = "0s"
  flush_interval = "15s"
  flush_jitter = "0s"
  precision = "0s"


[[inputs.cpu]]
  percpu = true
  totalcpu = true
  collect_cpu_time = false
  report_active = false
  core_tags = false


[[inputs.mem]]


[[inputs.swap]]


[[inputs.system]]
  fieldexclude = ["uptime_format"]

[[inputs.net]]
  interfaces = ["enp*"]


[[inputs.disk]]
  mount_points = ["/","/var/lib/docker/volumes","/usr/local/backup"]

[[inputs.diskio]]
  skip_serial_number = true


[[inputs.docker]]
  endpoint = "unix:///var/run/docker.sock"
  gather_services = false
  source_tag = false
  container_name_include = []
  container_name_exclude = []
  storage_objects = ["container", "image", "volume"]
  timeout = "5s"
  perdevice_include = ["cpu"]
  total_include = ["cpu", "blkio", "network"]
  docker_label_include = ["com_docker_compose_project", "container_name"]
  docker_label_exclude = ["container_id", "container_image", "container_status", "container_version", "server_version", "host"]
  namedrop = ["container_id", "container_image", "container_status", "container_version", "server_version", "host"]
  fieldexclude = ["container_id","health_status"]


[[outputs.http]]
  url = "http://10.4.0.3:9090/api/v1/write"
  data_format = "prometheusremotewrite"
  use_batch_format = true

  [outputs.http.headers]
    Content-Type = "application/x-protobuf"
    Content-Encoding = "snappy"
    X-Prometheus-Remote-Write-Version = "0.1.0"

Greetings!