[Metricbeat] Add Linux pressure metricset (elastic#27355)

* Adds new linux pressure metricset

* Tidy up code

* Be consistent in default config

* Run integration tests

* Make update

* make update v3

* Address comments

* Format tests

* Remove unused imports from tests

* Mage format

* Update changelog

* simplify loop

* Fix fields/mapping

CHANGELOG.next.asciidoc

@@ -102,6 +102,7 @@ https://github.com/elastic/beats/compare/v7.0.0-alpha2...master[Check the HEAD d
 - Added Airflow lightweight module {pull}26220[26220]
 - Add state_job metricset to Kubernetes module{pull}26479[26479]
 - Bump AWS SDK version to v0.24.0 for WebIdentity authentication flow {issue}19393[19393] {pull}27126[27126]
+- Add Linux pressure metricset {pull}27355[27355]
 
 *Packetbeat*
 

metricbeat/docs/fields.asciidoc

@@ -43509,6 +43509,242 @@ type: object
 
 --
 
+[float]
+=== pressure
+
+Linux pressure stall information metrics for cpu, memory, and io
+
+
+*`linux.pressure.cpu.some.10.pct`*::
++
+--
+The average share of time in which at least some tasks were stalled on CPU over a ten second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.cpu.some.60.pct`*::
++
+--
+The average share of time in which at least some tasks were stalled on CPU over a sixty second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.cpu.some.300.pct`*::
++
+--
+The average share of time in which at least some tasks were stalled on CPU over a three hundred second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.cpu.some.total.time.us`*::
++
+--
+The total absolute stall time (in microseconds) in which at least some tasks were stalled on CPU.
+
+
+type: long
+
+--
+
+*`linux.pressure.memory.some.10.pct`*::
++
+--
+The average share of time in which at least some tasks were stalled on Memory over a ten second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.memory.some.60.pct`*::
++
+--
+The average share of time in which at least some tasks were stalled on Memory over a sixty second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.memory.some.300.pct`*::
++
+--
+The average share of time in which at least some tasks were stalled on Memory over a three hundred second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.memory.some.total.time.us`*::
++
+--
+The total absolute stall time (in microseconds) in which at least some tasks were stalled on memory.
+
+
+type: long
+
+--
+
+*`linux.pressure.memory.full.10.pct`*::
++
+--
+The average share of time in which in which all non-idle tasks were stalled on memory simultaneously over a ten second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.memory.full.60.pct`*::
++
+--
+The average share of time in which in which all non-idle tasks were stalled on memory simultaneously over a sixty second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.memory.full.300.pct`*::
++
+--
+The average share of time in which in which all non-idle tasks were stalled on memory simultaneously over a three hundred second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.memory.full.total.time.us`*::
++
+--
+The total absolute stall time (in microseconds) in which in which all non-idle tasks were stalled on memory.
+
+
+type: long
+
+--
+
+*`linux.pressure.io.some.10.pct`*::
++
+--
+The average share of time in which at least some tasks were stalled on io over a ten second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.io.some.60.pct`*::
++
+--
+The average share of time in which at least some tasks were stalled on io over a sixty second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.io.some.300.pct`*::
++
+--
+The average share of time in which at least some tasks were stalled on io over a three hundred second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.io.some.total.time.us`*::
++
+--
+The total absolute stall time (in microseconds) in which at least some tasks were stalled on io.
+
+
+type: long
+
+--
+
+*`linux.pressure.io.full.10.pct`*::
++
+--
+The average share of time in which in which all non-idle tasks were stalled on io simultaneously over a ten second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.io.full.60.pct`*::
++
+--
+The average share of time in which in which all non-idle tasks were stalled on io simultaneously over a sixty second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.io.full.300.pct`*::
++
+--
+The average share of time in which in which all non-idle tasks were stalled on io simultaneously over a three hundred second window.
+
+
+type: float
+
+format: percent
+
+--
+
+*`linux.pressure.io.full.total.time.us`*::
++
+--
+The total absolute stall time (in microseconds) in which in which all non-idle tasks were stalled on io.
+
+
+type: long
+
+--
+
 [[exported-fields-logstash]]
 == Logstash fields
 

metricbeat/docs/modules/linux.asciidoc

@@ -26,6 +26,7 @@ metricbeat.modules:
     # - ksm
     # - conntrack
     # - iostat
+    # - pressure
   enabled: true
   #hostfs: /hostfs
 
@@ -46,6 +47,8 @@ The following metricsets are available:
 
 * <<metricbeat-metricset-linux-pageinfo,pageinfo>>
 
+* <<metricbeat-metricset-linux-pressure,pressure>>
+
 include::linux/conntrack.asciidoc[]
 
 include::linux/iostat.asciidoc[]
@@ -56,3 +59,5 @@ include::linux/memory.asciidoc[]
 
 include::linux/pageinfo.asciidoc[]
 
+include::linux/pressure.asciidoc[]
+

metricbeat/docs/modules/linux/pressure.asciidoc

@@ -0,0 +1,23 @@
+////
+This file is generated! See scripts/mage/docs_collector.go
+////
+
+[[metricbeat-metricset-linux-pressure]]
+=== linux pressure metricset
+
+beta[]
+
+include::../../../module/linux/pressure/_meta/docs.asciidoc[]
+
+
+==== Fields
+
+For a description of each field in the metricset, see the
+<<exported-fields-linux,exported fields>> section.
+
+Here is an example document generated by this metricset:
+
+[source,json]
+----
+include::../../../module/linux/pressure/_meta/data.json[]
+----

metricbeat/docs/modules_list.asciidoc

@@ -186,11 +186,12 @@ This file is generated! See scripts/mage/docs_collector.go
 .2+| .2+|  |<<metricbeat-metricset-kvm-dommemstat,dommemstat>> beta[]  
 |<<metricbeat-metricset-kvm-status,status>> beta[]  
 |<<metricbeat-module-linux,linux>>  beta[]   |image:./images/icon-no.png[No prebuilt dashboards]    |  
-.5+| .5+|  |<<metricbeat-metricset-linux-conntrack,conntrack>> beta[]  
+.6+| .6+|  |<<metricbeat-metricset-linux-conntrack,conntrack>> beta[]  
 |<<metricbeat-metricset-linux-iostat,iostat>> beta[]  
 |<<metricbeat-metricset-linux-ksm,ksm>> beta[]  
 |<<metricbeat-metricset-linux-memory,memory>> beta[]  
 |<<metricbeat-metricset-linux-pageinfo,pageinfo>> beta[]  
+|<<metricbeat-metricset-linux-pressure,pressure>> beta[]  
 |<<metricbeat-module-logstash,Logstash>>     |image:./images/icon-no.png[No prebuilt dashboards]    |  
 .2+| .2+|  |<<metricbeat-metricset-logstash-node,node>>   
 |<<metricbeat-metricset-logstash-node_stats,node_stats>>   

metricbeat/metricbeat.reference.yml

@@ -594,6 +594,7 @@ metricbeat.modules:
     # - ksm
     # - conntrack
     # - iostat
+    # - pressure
   enabled: true
   #hostfs: /hostfs
 

metricbeat/module/linux/_meta/config.yml

@@ -6,6 +6,7 @@
     # - ksm
     # - conntrack
     # - iostat
+    # - pressure
   enabled: true
   #hostfs: /hostfs
 

metricbeat/module/linux/pressure/_meta/data.json

@@ -0,0 +1,27 @@
+{
+    "@timestamp": "2017-10-12T08:05:34.853Z",
+    "event": {
+        "dataset": "linux.pressure",
+        "duration": 115000,
+        "module": "linux"
+    },
+    "linux": {
+        "pressure": {
+            "cpu": {
+                "some": {
+                    "10": 1.63,
+                    "300": 0.06,
+                    "60": 0.29,
+                    "total": 155911207
+                }
+            }
+        }
+    },
+    "metricset": {
+        "name": "pressure",
+        "period": 10000
+    },
+    "service": {
+        "type": "linux"
+    }
+}

metricbeat/module/linux/pressure/_meta/docs.asciidoc

@@ -0,0 +1 @@
+The Pressure module reports https://www.kernel.org/doc/Documentation/accounting/psi.txt[Pressure Stall Information (PSI)] collected for the `cpu`, `memory`, and `io` files/resources found in `/proc/pressure`. PSI metrics are included in Linux kernel versions from 4.20. Some distributions might have PSI support, but have disabled the feature via the `CONFIG_PSI_DEFAULT_DISABLED` setting, to enable PSI metrics pass `psi=1` on the kernel command line during boot.