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https://github.com/ncabatoff/process-exporter

Prometheus exporter that mines /proc to report on selected processes
https://github.com/ncabatoff/process-exporter

go process-metrics prometheus-exporter

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Prometheus exporter that mines /proc to report on selected processes

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# process-exporter

Prometheus exporter that mines /proc to report on selected processes.



[release]: https://github.com/ncabatoff/process-exporter/releases/latest



[![Release](https://img.shields.io/github/release/ncabatoff/process-exporter.svg?style=flat-square")][release]

[![Powered By: GoReleaser](https://img.shields.io/badge/powered%20by-goreleaser-green.svg?branch=master)](https://github.com/goreleaser)

![Build](https://github.com/ncabatoff/process-exporter/actions/workflows/build.yml/badge.svg)



Some apps are impractical to instrument directly, either because you

don't control the code or they're written in a language that isn't easy to

instrument with Prometheus.  We must instead resort to mining /proc.



## Installation



Either grab a package for your OS from the [Releases][release] page, or

install via [docker](https://hub.docker.com/r/ncabatoff/process-exporter/).



## Running



Usage:



```

  process-exporter [options] -config.path filename.yml

```



or via docker:



```

  docker run -d --rm -p 9256:9256 --privileged -v /proc:/host/proc -v `pwd`:/config ncabatoff/process-exporter --procfs /host/proc -config.path /config/filename.yml



```



Important options (run process-exporter --help for full list):



-children (default:true) makes it so that any process that otherwise

isn't part of its own group becomes part of the first group found (if any) when

walking the process tree upwards.  In other words, resource usage of

subprocesses is added to their parent's usage unless the subprocess identifies

as a different group name.



-threads (default:true) means that metrics will be broken down by thread name

as well as group name.



-recheck (default:false) means that on each scrape the process names are

re-evaluated. This is disabled by default as an optimization, but since

processes can choose to change their names, this may result in a process

falling into the wrong group if we happen to see it for the first time before

it's assumed its proper name. You can use -recheck-with-time-limit to enable this

feature only for a specific duration after process starts.



-procnames is intended as a quick alternative to using a config file.  Details

in the following section.



To disable any of these options, use the `-option=false`.



## Configuration and group naming



To select and group the processes to monitor, either provide command-line

arguments or use a YAML configuration file.



The recommended option is to use a config file via -config.path, but for

convenience and backwards compatibility the -procnames/-namemapping options

exist as an alternative.



### Using a config file



The general format of the -config.path YAML file is a top-level

`process_names` section, containing a list of name matchers:



```

process_names:

  - matcher1

  - matcher2

  ...

  - matcherN

```



The default config shipped with the deb/rpm packages is:



```

process_names:

  - name: "{{.Comm}}"

    cmdline:

    - '.+'

```



A process may only belong to one group: even if multiple items would match, the

first one listed in the file wins.



(Side note: to avoid confusion with the cmdline YAML element, we'll refer to

the command-line arguments of a process `/proc//cmdline` as the array

`argv[]`.)



#### Using a config file: group name



Each item in `process_names` gives a recipe for identifying and naming

processes.  The optional `name` tag defines a template to use to name

matching processes; if not specified, `name` defaults to `{{.ExeBase}}`.



Template variables available:

- `{{.Comm}}` contains the basename of the original executable, i.e. 2nd field in `/proc//stat`

- `{{.ExeBase}}` contains the basename of the executable

- `{{.ExeFull}}` contains the fully qualified path of the executable

- `{{.Username}}` contains the username of the effective user

- `{{.Matches}}` map contains all the matches resulting from applying cmdline regexps

- `{{.PID}}` contains the PID of the process.  Note that using PID means the group

  will only contain a single process.

- `{{.StartTime}}` contains the start time of the process.  This can be useful

  in conjunction with PID because PIDs get reused over time.

- `{{.Cgroups}}` contains (if supported) the cgroups of the process

  (`/proc/self/cgroup`). This is particularly useful for identifying to which container

  a process belongs.



Using `PID` or `StartTime` is discouraged: this is almost never what you want,

and is likely to result in high cardinality metrics which Prometheus will have

trouble with.



#### Using a config file: process selectors



Each item in `process_names` must contain one or more selectors (`comm`, `exe`

or `cmdline`); if more than one selector is present, they must all match.  Each

selector is a list of strings to match against a process's `comm`, `argv[0]`,

or in the case of `cmdline`, a regexp to apply to the command line.  The cmdline

regexp uses the [Go syntax](https://golang.org/pkg/regexp).



For `comm` and `exe`, the list of strings is an OR, meaning any process

matching any of the strings will be added to the item's group.



For `cmdline`, the list of regexes is an AND, meaning they all must match.  Any

capturing groups in a regexp must use the `?P` option to assign a name to

the capture, which is used to populate `.Matches`.



Performance tip: give an exe or comm clause in addition to any cmdline

clause, so you avoid executing the regexp when the executable name doesn't

match.



```



process_names:

  # comm is the second field of /proc//stat minus parens.

  # It is the base executable name, truncated at 15 chars.

  # It cannot be modified by the program, unlike exe.

  - comm:

    - bash



  # exe is argv[0]. If no slashes, only basename of argv[0] need match.

  # If exe contains slashes, argv[0] must match exactly.

  - exe:

    - postgres

    - /usr/local/bin/prometheus



  # cmdline is a list of regexps applied to argv.

  # Each must match, and any captures are added to the .Matches map.

  - name: "{{.ExeFull}}:{{.Matches.Cfgfile}}"

    exe:

    - /usr/local/bin/process-exporter

    cmdline:

    - -config.path\s+(?P\S+)



```



Here's the config I use on my home machine:



```



process_names:

  - comm:

    - chromium-browse

    - bash

    - prometheus

    - gvim

  - exe:

    - /sbin/upstart

    cmdline:

    - --user

    name: upstart:-user



```



### Using -procnames/-namemapping instead of config.path



Every name in the procnames list becomes a process group. The default name of

a process is the value found in the second field of /proc//stat

("comm"), which is truncated at 15 chars.  Usually this is the same as the

name of the executable.



If -namemapping isn't provided, every process with a comm value present

in -procnames is assigned to a group based on that name, and any other

processes are ignored.



The -namemapping option is a comma-separated list of alternating

name,regexp values. It allows assigning a name to a process based on a

combination of the process name and command line. For example, using



  -namemapping "python2,([^/]+)\.py,java,-jar\s+([^/]+).jar"



will make it so that each different python2 and java -jar invocation will be

tracked with distinct metrics. Processes whose remapped name is absent from

the procnames list will be ignored. On a Ubuntu Xenian machine being used as

a workstation, here's a good way of tracking resource usage for a few

different key user apps:



  process-exporter -namemapping "upstart,(--user)" \

    -procnames chromium-browse,bash,gvim,prometheus,process-exporter,upstart:-user



Since upstart --user is the parent process of the X11 session, this will

make all apps started by the user fall into the group named "upstart:-user",

unless they're one of the others named explicitly with -procnames, like gvim.



## Group Metrics



There's no meaningful way to name a process that will only ever name a single process, so process-exporter assumes that every metric will be attached

to a group of processes - not a

[process group](https://en.wikipedia.org/wiki/Process_group) in the technical

sense, just one or more processes that meet a configuration's specification

of what should be monitored and how to name it.



All these metrics start with `namedprocess_namegroup_` and have at minimum

the label `groupname`.



### num_procs gauge



Number of processes in this group.



### cpu_seconds_total counter



CPU usage based on /proc/[pid]/stat fields utime(14) and stime(15) i.e. user and system time. This is similar to the node\_exporter's `node_cpu_seconds_total`.



### read_bytes_total counter



Bytes read based on /proc/[pid]/io field read_bytes.  The man page

says



> Attempt to count the number of bytes which this process really did cause to be fetched from the storage layer.  This is accurate for block-backed filesystems.



but I would take it with a grain of salt.



As `/proc/[pid]/io` are set by the kernel as read only to the process' user (see #137), to get these values you should run `process-exporter` either as that user or as `root`. Otherwise, we can't read these values and you'll get a constant 0 in the metric.



### write_bytes_total counter



Bytes written based on /proc/[pid]/io field write_bytes.  As with

read_bytes, somewhat dubious.  May be useful for isolating which processes

are doing the most I/O, but probably not measuring just how much I/O is happening.



### major_page_faults_total counter



Number of major page faults based on /proc/[pid]/stat field majflt(12).



### minor_page_faults_total counter



Number of minor page faults based on /proc/[pid]/stat field minflt(10).



### context_switches_total counter



Number of context switches based on /proc/[pid]/status fields voluntary_ctxt_switches

and nonvoluntary_ctxt_switches.  The extra label `ctxswitchtype` can have two values:

`voluntary` and `nonvoluntary`.



### memory_bytes gauge



Number of bytes of memory used.  The extra label `memtype` can have three values:



*resident*: Field rss(24) from /proc/[pid]/stat, whose doc says:



> This is just the pages which count toward text, data, or stack space.  This does not include pages which have not been demand-loaded in, or which are swapped out.



*virtual*: Field vsize(23) from /proc/[pid]/stat, virtual memory size.



*swapped*: Field VmSwap from /proc/[pid]/status, translated from KB to bytes.



If gathering smaps file is enabled, two additional values for `memtype` are added:



*proportionalResident*: Sum of "Pss" fields from /proc/[pid]/smaps, whose doc says:



> The "proportional set size" (PSS) of a process is the count of pages it has

> in memory, where each page is divided by the number of processes sharing it.



*proportionalSwapped*: Sum of "SwapPss" fields from /proc/[pid]/smaps



### open_filedesc gauge



Number of file descriptors, based on counting how many entries are in the directory

/proc/[pid]/fd.



### worst_fd_ratio gauge



Worst ratio of open filedescs to filedesc limit, amongst all the procs in the

group. The limit is the fd soft limit based on /proc/[pid]/limits.



Normally Prometheus metrics ought to be as "basic" as possible (i.e. the raw

values rather than a derived ratio), but we use a ratio here because nothing

else makes sense. Suppose there are 10 procs in a given group, each with a

soft limit of 4096, and one of them has 4000 open fds and the others all have

40, their total fdcount is 4360 and total soft limit is 40960, so the ratio

is 1:10, but in fact one of the procs is about to run out of fds. With

worst_fd_ratio we're able to know this: in the above example it would be

0.97, rather than the 0.10 you'd see if you computed sum(open_filedesc) /

sum(limit_filedesc).



### oldest_start_time_seconds gauge



Epoch time (seconds since 1970/1/1) at which the oldest process in the group

started.  This is derived from field starttime(22) from /proc/[pid]/stat, added

to boot time to make it relative to epoch.



### num_threads gauge



Sum of number of threads of all process in the group.  Based on field num_threads(20)

from /proc/[pid]/stat.



### states gauge



Number of threads in the group in each of various states, based on the field

state(3) from /proc/[pid]/stat.



The extra label `state` can have these values: `Running`, `Sleeping`, `Waiting`, `Zombie`, `Other`.



## Group Thread Metrics



Since publishing thread metrics adds a lot of overhead, use the `-threads` command-line argument to disable them, 

if necessary.



All these metrics start with `namedprocess_namegroup_` and have at minimum

the labels `groupname` and `threadname`.  `threadname` is field comm(2) from

/proc/[pid]/stat.  Just as groupname breaks the set of processes down into

groups, threadname breaks a given process group down into subgroups.



### thread_count gauge



Number of threads in this thread subgroup.



### thread_cpu_seconds_total counter



Same as cpu_user_seconds_total and cpu_system_seconds_total, but broken down

per-thread subgroup.  Unlike cpu_user_seconds_total/cpu_system_seconds_total,

the label `cpumode` is used to distinguish between `user` and `system` time.



### thread_io_bytes_total counter



Same as read_bytes_total and write_bytes_total, but broken down

per-thread subgroup.  Unlike read_bytes_total/write_bytes_total,

the label `iomode` is used to distinguish between `read` and `write` bytes.



### thread_major_page_faults_total counter



Same as major_page_faults_total, but broken down per-thread subgroup.



### thread_minor_page_faults_total counter



Same as minor_page_faults_total, but broken down per-thread subgroup.



### thread_context_switches_total counter



Same as context_switches_total, but broken down per-thread subgroup.



## Instrumentation cost



process-exporter will consume CPU in proportion to the number of processes in

the system and the rate at which new ones are created.  The most expensive

parts - applying regexps and executing templates - are only applied once per

process seen, unless the command-line option -recheck is provided.



If you have mostly long-running processes process-exporter overhead should be

minimal: each time a scrape occurs, it will parse of /proc/$pid/stat and

/proc/$pid/cmdline for every process being monitored and add a few numbers.



## Dashboards



An example Grafana dashboard to view the metrics is available at https://grafana.net/dashboards/249



## Building



Requires Go 1.21 (at least) installed.

```

make

```



## Exposing metrics through HTTPS



web-config.yml

```

# Minimal TLS configuration example. Additionally, a certificate and a key file

# are needed.

tls_server_config:

  cert_file: server.crt

  key_file: server.key

```

Running

```

$ ./process-exporter -web.config.file web-config.yml &

$ curl -sk https://localhost:9256/metrics | grep process



# HELP namedprocess_scrape_errors general scrape errors: no proc metrics collected during a cycle

# TYPE namedprocess_scrape_errors counter

namedprocess_scrape_errors 0

# HELP namedprocess_scrape_partial_errors incremented each time a tracked proc's metrics collection fails partially, e.g. unreadable I/O stats

# TYPE namedprocess_scrape_partial_errors counter

namedprocess_scrape_partial_errors 0

# HELP namedprocess_scrape_procread_errors incremented each time a proc's metrics collection fails

# TYPE namedprocess_scrape_procread_errors counter

namedprocess_scrape_procread_errors 0

# HELP process_cpu_seconds_total Total user and system CPU time spent in seconds.

# TYPE process_cpu_seconds_total counter

process_cpu_seconds_total 0.21

# HELP process_exporter_build_info A metric with a constant '1' value labeled by version, revision, branch, and goversion from which process_exporter was built.

# TYPE process_exporter_build_info gauge

process_exporter_build_info{branch="",goversion="go1.17.3",revision="",version=""} 1

# HELP process_max_fds Maximum number of open file descriptors.

# TYPE process_max_fds gauge

process_max_fds 1.048576e+06

# HELP process_open_fds Number of open file descriptors.

# TYPE process_open_fds gauge

process_open_fds 10

```



For further information about TLS configuration, please visit: [exporter-toolkit](https://github.com/prometheus/exporter-toolkit/blob/master/docs/web-configuration.md)