---
title: Telegraf Documentation
description: Telegraf plugin for collecting metrics from Kernel
url: https://docs.influxdata.com/telegraf/v1/input-plugins/kernel/
estimated_tokens: 2075
product: Telegraf
version: v1
---

-   Telegraf v0.11.0+

# Kernel Input Plugin

This plugin gathers metrics about the [Linux kernel](https://kernel.org/) including, among others, the [available entropy](https://www.kernel.org/doc/html/latest/admin-guide/sysctl/kernel.html#random), [Kernel Samepage Merging](https://www.kernel.org/doc/html/latest/mm/ksm.html) and [Pressure Stall Information](https://www.kernel.org/doc/html/latest/accounting/psi.html).

**Introduced in:** Telegraf v0.11.0 **Tags:** system **OS support:** linux

## Global configuration options

Plugins support additional global and plugin configuration settings for tasks such as modifying metrics, tags, and fields, creating aliases, and configuring plugin ordering. See [CONFIGURATION.md](/telegraf/v1/configuration/#plugins) for more details.

## Configuration

```toml
# 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](http://man7.org/linux/man-pages/man5/proc.5.html), as well as in the `/proc interfaces` section of the [random man page](https://man7.org/linux/man-pages/man4/random.4.html).

Kernel Samepage Merging is generally documented in the [kernel documentation](https://www.kernel.org/doc/html/latest/mm/ksm.html) and the available metrics exposed via sysfs are documented in the [admin guide](https://www.kernel.org/doc/html/latest/admin-guide/mm/ksm.html#ksm-daemon-sysfs-interface).

Pressure Stall Information is exposed through `/proc/pressure` and is documented in [kernel documentation](https://www.kernel.org/doc/html/latest/accounting/psi.html). Kernel version 4.20+ is required.

## Metrics

-   kernel
    
    -   boot\_time (int) - seconds since epoch, `btime`
    -   context\_switches (int) - number of context switches `ctxt`
    -   disk\_pages\_in (int) - `page (0)`
    -   disk\_pages\_out (int) - `page (1)`
    -   interrupts (int) - number of interrupts `intr`
    -   processes\_forked (int) - number of forked processes `processes`
    -   entropy\_avail (int) - entropy currently available `entropy_available`
    -   ksm\_full\_scans (int) - number of scans of all mergeable areas `full_scans`
    -   ksm\_max\_page\_sharing (int) - maximum sharing allowed for each KSM page `max_page_sharing`
    -   ksm\_merge\_across\_nodes (int) - flag for merging of pages across NUMA nodes `merge_across_nodes`
    -   ksm\_pages\_shared (int) - number of shared pages are being used `pages_shared`
    -   ksm\_pages\_sharing (int) - number of sites sharing pages `pages_sharing`
    -   ksm\_pages\_to\_scan (int) - number of pages to scan before ksmd sleep `pages_to_scan`
    -   ksm\_pages\_unshared (int) - number of pages unique but repeatedly checked for merging `pages_unshared`
    -   ksm\_pages\_volatile (int) - number of pages changing too fast to be placed in a tree `pages_volatile`
    -   ksm\_run (int) - flag for ksm is running or not `run`
    -   ksm\_sleep\_millisecs (int) - sleep time for ksmd between scans `sleep_millisecs`
    -   ksm\_stable\_node\_chains (int) - number of KSM pages hitting the max\_page\_sharing limit `stable_node_chains`
    -   ksm\_stable\_node\_chains\_prune\_millisecs (int) - frequency for KSM checks of page metadata hitting the deduplication limit `stable_node_chains_prune_millisecs`
    -   ksm\_stable\_node\_dups (int) - number of duplicated KSM pages, `stable_node_dups`
    -   ksm\_use\_zero\_pages (int) - flag for empty pages being 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:

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

If `ksm` is included in `collect`:

```text
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`:

```text
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.

#### Related

-   [Configure plugins](/telegraf/v1/configure_plugins/)
-   [Kernel Plugin Source](https://github.com/influxdata/telegraf/tree/v1.38.4/plugins/inputs/kernel/README.md)