Sensu Disk Checks Plugin

• Overview
• Usage examples
• Configuration
  • Sensu Go
    • Asset definition
    • Check definition
  • Sensu Core
    • Check definition
• Functionality
• Additional information
• Installation from source and contributing

Overview

This plugin provides native disk instrumentation for monitoring and metrics collection, including: health, usage, and various metrics.

The Sensu assets packaged from this repository are built against the Sensu ruby runtime environment. When using these assets as part of a Sensu Go resource (check, mutator or handler), make sure you include the corresponding Sensu ruby runtime asset in the list of assets needed by the resource. The current ruby-runtime assets can be found here in the Bonsai Asset Index

Files

• bin/check-disk-usage.rb
• bin/check-fstab-mounts.rb
• bin/check-smart-status.rb
• bin/check-smart.rb
• bin/check-smart-tests.rb
• bin/metrics-disk.rb
• bin/metrics-disk-capacity.rb
• bin/metrics-disk-usage.rb

Usage examples

Help

check-disk-usage.rb

Usage: check-disk-usage.rb (options)
    -c PERCENT                       Critical if PERCENT or more of disk full
    -w PERCENT                       Warn if PERCENT or more of disk full
    -t TYPE[,TYPE]                   Only check fs type(s)
    -K PERCENT                       Critical if PERCENT or more of inodes used
    -i MNT[,MNT]                     Ignore mount point(s)
    -o TYPE[.TYPE]                   Ignore option(s)
    -p PATHRE                        Ignore mount point(s) matching regular expression
    -x TYPE[,TYPE]                   Ignore fs type(s)
    -I MNT[,MNT]                     Include only mount point(s)
    -r                               Ignore bytes reserved for privileged processes only
    -W PERCENT                       Warn if PERCENT or more of inodes used
    -m MAGIC                         Magic factor to adjust warn/crit thresholds. Example: .9
    -l MINIMUM                       Minimum size to adjust (in GB)
    -n NORMAL                        Levels are not adapted for filesystems of exactly this size, where levels are reduced for smaller filesystems and raised for larger filesystems.

metrics-disk-usage.rb

Usage: metrics-disk-usage.rb (options)
    -B, --block-size BLOCK_SIZE      Set block size for sizes printed
    -f, --flatten                    Output mounts with underscore rather than dot
    -i, --ignore-mount MNT[,MNT]     Ignore mounts matching pattern(s)
    -I, --include-mount MNT[,MNT]    Include only mounts matching pattern(s)
    -l, --local                      Only check local filesystems (df -l option)
        --scheme SCHEME              Metric naming scheme, text to prepend to .$parent.$child

Configuration

Sensu Go

Asset registration

Assets are the best way to make use of this plugin. If you're not using an asset, please consider doing so! If you're using sensuctl 5.13 or later, you can use the following command to add the asset:

sensuctl asset add sensu-plugins/sensu-plugins-disk-checks

If you're using an earlier version of sensuctl, you can download the asset definition from this project's Bonsai Asset Index page.

Asset definition

---
type: Asset
api_version: core/v2
metadata:
  name: sensu-plugins-disk-checks
spec:
  url: https://assets.bonsai.sensu.io/73a6f8b6f56672630d83ec21676f9a6251094475/sensu-plugins-disk-checks_5.0.0_centos_linux_amd64.tar.gz
  sha512: 0ce9d52b270b77f4cab754e55732ae002228201d0bd01a89b954a0655b88c1ee6546e2f82cfd1eec04689af90ad940cde128e8867912d9e415f4a58d7fdcdadf

Check definition

---
type: CheckConfig
spec:
  command: "metrics-disk-usage.rb"
  handlers: []
  high_flap_threshold: 0
  interval: 10
  low_flap_threshold: 0
  publish: true
  runtime_assets:
  - sensu-plugins/sensu-plugins-disk-checks
  - sensu/sensu-ruby-runtime
  subscriptions:
  - linux
  output_metric_format: graphite_plaintext
  output_metric_handlers:
  - influx-db

Sensu Core

Check definition

{
  "checks": {
    "metrics-disk-usage": {
      "command": "metric-disk-usage.rb",
      "subscribers": ["linux"],
      "interval": 10,
      "refresh": 10,
      "handlers": ["influxdb"]
    }
  }
}

Functionality

check-disk-usage

Check disk capacity and inodes based upon the gem sys-filesystem.

Can adjust thresholds for larger filesystems by providing a 'magic factor'
(-m). The default, 1.0, will not adapt threshold percentages for volumes.

The -l option can be used in combination with the 'magic factor' to specify
the minimum size volume to adjust the thresholds for.

By default all mounted filesystems are checked.

The -x option can be used to exclude one or more filesystem types. e.g.

check-disk-usage.rb -x debugfs,tracefs

The -p option can be used to exlucde specific mount points. e.g.

check-disk-usage.rb -p /run/lxcfs

It's also possible to use regular expressions with the -x or -p option

check-disk-usage.rb -p '(\/var|\/run|\/sys|\/snap)'

Refer to check_mk's
documentation on adaptive thresholds.

You can also visualize the adjustment using
WolframAlpha with the following:

y = 100 - (100-P)*(N^(1-m))/(x^(1-m)), y = P for x in 0 to 1024

Where P = base percentage, N = normalize factor, and m = magic factor

check-fstab-mounts

Check the mount points in /etc/fstab to ensure they are all accounted for.

metrics-disk-capacity

Acquire disk capacity metrics from df and convert them to a form usable by graphite

metrics-disk

Read /proc/iostats for disk metrics and put them in a form usable by Graphite. See iostats.txt for more details.

metrics-disk-usage

Based on disk-capacity-metrics.rb by bhenerey and nstielau. The difference here being how the key is defined in graphite and the size we emit to graphite(now using megabytes), inode info has also been dropped.

check-smart-status

Check the SMART status of hardrives and alert based upon a given set of thresholds

check-smart

Check the health of a disk using smartctl

check-smart-tests

Check the status of SMART offline tests and optionally check if tests were executed in a specified interval

Additional information

The check-smart.rb and check-smart-status.rb scripts can make use of a json file living on disk in /etc/sensu/conf.dwith the name smart.json. You can see a sample input file used by these scripts below. Please refer to the individual scripts for further details.

{
  "smart": {
    "attributes": [
      { "id": 1, "name": "Raw_read_Error_Rate", "read": "left16bit" },
      { "id": 5, "name": "Reallocated_Sector_Ct" },
      { "id": 9, "name": "Power_On_Hours", "read": "right16bit", "warn_max": 10000, "crit_max": 15000 },
      { "id": 10 , "name": "Spin_Retry_Count" },
      { "id": 184, "name": "End-to-End_Error" },
      { "id": 187, "name": "Reported_Uncorrect" },
      { "id": 188, "name": "Command_Timeout" },
      { "id": 193, "name": "Load_Cycle_Count", "warn_max": 300000, "crit_max": 600000 },
      { "id": 194, "name": "Temperature_Celsius", "read": "right16bit", "crit_min": 20, "warn_min": 10, "warn_max": 40, "crit_max": 50 },
      { "id": 196, "name": "Reallocated_Event_Count" },
      { "id": 197, "name": "Current_Pending_Sector" },
      { "id": 198, "name": "Offline_Uncorrectable" },
      { "id": 199, "name": "UDMA_CRC_Error_Count" },
      { "id": 201, "name": "Unc_Soft_read_Err_Rate", "read": "left16bit" },
      { "id": 230, "name": "Life_Curve_Status", "crit_min": 100, "warn_min": 100, "warn_max": 100, "crit_max": 100 }
    ]
  },
  "hardware": {
    "devices": [
	  { "path": "sda", "ignore" : [ 187 ] },
	  { "path": "sdb", "override": "/dev/twa0 -d 3ware,0" }
	]
  }
}

Installation

Sensu Go

See the instructions above for asset registration

Sensu Core

Install and setup plugins on Sensu Core

Certification Verification

If you are verifying certificates in the gem install you will need the certificate for the sys-filesystem gem loaded in the gem certificate store. That cert can be found here.