kernel

README

Kernel Input Plugin

This plugin gathers metrics about the Linux kernel including, among others, the available entropy, Kernel Samepage Merging and Pressure Stall Information.

⭐ Telegraf v0.11.0 🏷️ system 💻 linux

Global configuration options

In addition to the plugin-specific configuration settings, plugins support additional global and plugin configuration settings. These settings are used to modify metrics, tags, and field or create aliases and configure ordering, etc. See the CONFIGURATION.md for more details.

Configuration

# Plugin to collect various Linux kernel statistics.
# This plugin ONLY supports Linux
[[inputs.kernel]]
  ## Additional gather options
  ## Possible options include:
  ## * ksm - kernel same-page merging
  ## * psi - pressure stall information
  # collect = []

Please check the documentation of the underlying kernel interfaces in the /proc/stat section of the proc man page, as well as in the /proc interfaces section of the random man page.

Kernel Samepage Merging is generally documented in the kernel documentation and the available metrics exposed via sysfs are documented in the admin guide.

Pressure Stall Information is exposed through /proc/pressure and is documented in kernel documentation. Kernel version 4.20+ is required.

Metrics

• kernel

  • boot_time (integer, seconds since epoch, btime)
  • context_switches (integer, ctxt)
  • disk_pages_in (integer, page (0))
  • disk_pages_out (integer, page (1))
  • interrupts (integer, intr)
  • processes_forked (integer, processes)
  • entropy_avail (integer, entropy_available)
  • ksm_full_scans (integer, how many times all mergeable areas have been scanned, full_scans)
  • ksm_max_page_sharing (integer, maximum sharing allowed for each KSM page, max_page_sharing)
  • ksm_merge_across_nodes (integer, whether pages should be merged across NUMA nodes, merge_across_nodes)
  • ksm_pages_shared (integer, how many shared pages are being used, pages_shared)
  • ksm_pages_sharing (integer,how many more sites are sharing them , pages_sharing)
  • ksm_pages_to_scan (integer, how many pages to scan before ksmd goes to sleep, pages_to_scan)
  • ksm_pages_unshared (integer, how many pages unique but repeatedly checked for merging, pages_unshared)
  • ksm_pages_volatile (integer, how many pages changing too fast to be placed in a tree, pages_volatile)
  • ksm_run (integer, whether ksm is running or not, run)
  • ksm_sleep_millisecs (integer, how many milliseconds ksmd should sleep between scans, sleep_millisecs)
  • ksm_stable_node_chains (integer, the number of KSM pages that hit the max_page_sharing limit, stable_node_chains)
  • ksm_stable_node_chains_prune_millisecs (integer, how frequently KSM checks the metadata of the pages that hit the deduplication limit, stable_node_chains_prune_millisecs)
  • ksm_stable_node_dups (integer, number of duplicated KSM pages, stable_node_dups)
  • ksm_use_zero_pages (integer, whether empty pages should be treated specially, use_zero_pages)

• pressure (if psi is included in collect)

  • tags:
    • resource: cpu, memory, or io
    • type: some or full
  • floating-point fields: avg10, avg60, avg300
  • integer fields: total

Example Output

Default config:

kernel boot_time=1690487872i,context_switches=321398652i,entropy_avail=256i,interrupts=141868628i,processes_forked=946492i 1691339564000000000

If ksm is included in collect:

kernel boot_time=1690487872i,context_switches=321252729i,entropy_avail=256i,interrupts=141783427i,ksm_full_scans=0i,ksm_max_page_sharing=256i,ksm_merge_across_nodes=1i,ksm_pages_shared=0i,ksm_pages_sharing=0i,ksm_pages_to_scan=100i,ksm_pages_unshared=0i,ksm_pages_volatile=0i,ksm_run=0i,ksm_sleep_millisecs=20i,ksm_stable_node_chains=0i,ksm_stable_node_chains_prune_millisecs=2000i,ksm_stable_node_dups=0i,ksm_use_zero_pages=0i,processes_forked=946467i 1691339522000000000

If psi is included in collect:

pressure,resource=cpu,type=some avg10=1.53,avg60=1.87,avg300=1.73 1700000000000000000
pressure,resource=memory,type=some avg10=0.00,avg60=0.00,avg300=0.00 1700000000000000000
pressure,resource=memory,type=full avg10=0.00,avg60=0.00,avg300=0.00 1700000000000000000
pressure,resource=io,type=some avg10=0.0,avg60=0.0,avg300=0.0 1700000000000000000
pressure,resource=io,type=full avg10=0.0,avg60=0.0,avg300=0.0 1700000000000000000
pressure,resource=cpu,type=some total=1088168194i 1700000000000000000
pressure,resource=memory,type=some total=3463792i 1700000000000000000
pressure,resource=memory,type=full total=1429641i 1700000000000000000
pressure,resource=io,type=some total=68568296i 1700000000000000000
pressure,resource=io,type=full total=54982338i 1700000000000000000

Note that the combination for resource=cpu,type=full is omitted because it is always zero.

Documentation

Index

• type Kernel
  • func (k *Kernel) Gather(acc telegraf.Accumulator) error
  • func (k *Kernel) Init() error
  • func (*Kernel) SampleConfig() string

Types

type Kernel

type Kernel struct {
	ConfigCollect []string `toml:"collect"`
	// contains filtered or unexported fields
}

func (*Kernel) Gather

func (k *Kernel) Gather(acc telegraf.Accumulator) error

func (*Kernel) Init

func (k *Kernel) Init() error

func (*Kernel) SampleConfig

func (*Kernel) SampleConfig() string