COLLECTD-THRESHOLD(5) collectd COLLECTD-THRESHOLD(5)
NAME
collectd-threshold - Documentation of collectd's Threshold plugin
SYNOPSIS
LoadPlugin "threshold"
<Plugin "threshold">
<Type "foo">
WarningMin 0.00
WarningMax 1000.00
FailureMin 0.00
FailureMax 1200.00
Invert false
Instance "bar"
</Type>
</Plugin>
DESCRIPTION
Starting with version 4.3.0 collectd has support for monitoring. By
that we mean that the values are not only stored or sent somewhere, but
that they are judged and, if a problem is recognized, acted upon. The
only action the Threshold plugin takes itself is to generate and
dispatch a notification. Other plugins can register to receive
notifications and perform appropriate further actions.
Since systems and what you expect them to do differ a lot, you can
configure thresholds for your values freely. This gives you a lot of
flexibility but also a lot of responsibility.
Every time a value is out of range, a notification is dispatched. This
means that the idle percentage of your CPU needs to be less then the
configured threshold only once for a notification to be generated.
There's no such thing as a moving average or similar - at least not
now.
Also, all values that match a threshold are considered to be relevant
or "interesting". As a consequence collectd will issue a notification
if they are not received for Timeout iterations. The Timeout
configuration option is explained in section "GLOBAL OPTIONS" in
collectd.conf(5). If, for example, Timeout is set to "2" (the default)
and some hosts sends its CPU statistics to the server every 60 seconds,
a notification will be dispatched after about 120 seconds. It may take
a little longer because the timeout is checked only once each Interval
on the server.
When a value comes within range again or is received after it was
missing, an "OKAY-notification" is dispatched.
CONFIGURATION
Here is a configuration example to get you started. Read below for more
information.
LoadPlugin "threshold"
<Plugin "threshold">
<Type "foo">
WarningMin 0.00
WarningMax 1000.00
FailureMin 0.00
FailureMax 1200.00
Invert false
Instance "bar"
</Type>
<Plugin "interface">
Instance "eth0"
<Type "if_octets">
FailureMax 10000000
DataSource "rx"
</Type>
</Plugin>
<Host "hostname">
<Type "cpu">
Instance "idle"
FailureMin 10
</Type>
<Plugin "memory">
<Type "memory">
Instance "cached"
WarningMin 100000000
</Type>
</Plugin>
<Type "load">
DataSource "midterm"
FailureMax 4
Hits 3
Hysteresis 3
</Type>
</Host>
</Plugin>
There are basically two types of configuration statements: The "Host",
"Plugin", and "Type" blocks select the value for which a threshold
should be configured. The "Plugin" and "Type" blocks may be specified
further using the "Instance" option. You can combine the block by
nesting the blocks, though they must be nested in the above order, i.e.
"Host" may contain either "Plugin" and "Type" blocks, "Plugin" may only
contain "Type" blocks and "Type" may not contain other blocks. If
multiple blocks apply to the same value the most specific block is
used.
The other statements specify the threshold to configure. They must be
included in a "Type" block. Currently the following statements are
recognized:
FailureMax Value
WarningMax Value
Sets the upper bound of acceptable values. If unset defaults to
positive infinity. If a value is greater than FailureMax a FAILURE
notification will be created. If the value is greater than
WarningMax but less than (or equal to) FailureMax a WARNING
notification will be created.
FailureMin Value
WarningMin Value
Sets the lower bound of acceptable values. If unset defaults to
negative infinity. If a value is less than FailureMin a FAILURE
notification will be created. If the value is less than WarningMin
but greater than (or equal to) FailureMin a WARNING notification
will be created.
DataSource DSName
Some data sets have more than one "data source". Interesting
examples are the "if_octets" data set, which has received ("rx")
and sent ("tx") bytes and the "disk_ops" data set, which holds
"read" and "write" operations. The system load data set, "load",
even has three data sources: "shortterm", "midterm", and
"longterm".
Normally, all data sources are checked against a configured
threshold. If this is undesirable, or if you want to specify
different limits for each data source, you can use the DataSource
option to have a threshold apply only to one data source.
Invert true|false
If set to true the range of acceptable values is inverted, i.e.
values between FailureMin and FailureMax (WarningMin and
WarningMax) are not okay. Defaults to false.
Persist true|false
Sets how often notifications are generated. If set to true one
notification will be generated for each value that is out of the
acceptable range. If set to false (the default) then a notification
is only generated if a value is out of range but the previous value
was okay.
This applies to missing values, too: If set to true a notification
about a missing value is generated once every Interval seconds. If
set to false only one such notification is generated until the
value appears again.
PersistOK true|false
Sets how OKAY notifications act. If set to true one notification
will be generated for each value that is in the acceptable range.
If set to false (the default) then a notification is only generated
if a value is in range but the previous value was not.
Percentage true|false
If set to true, the minimum and maximum values given are
interpreted as percentage value, relative to the other data
sources. This is helpful for example for the "df" type, where you
may want to issue a warning when less than 5 % of the total space
is available. Defaults to false.
Hits Value
Sets the number of occurrences which the threshold must be raised
before to dispatch any notification or, in other words, the number
of Intervals that the threshold must be match before dispatch any
notification.
Hysteresis Value
Sets the hysteresis value for threshold. The hysteresis is a method
to prevent flapping between states, until a new received value for
a previously matched threshold down below the threshold condition
(WarningMax, FailureMin or everything else) minus the hysteresis
value, the failure (respectively warning) state will be keep.
Interesting true|false
If set to true (the default), a notification with severity
"FAILURE" will be created when a matching value list is no longer
updated and purged from the internal cache. When this happens
depends on the interval of the value list and the global Timeout
setting. See the Interval and Timeout settings in collectd.conf(5)
for details. If set to false, this event will be ignored.
SEE ALSO
collectd(1), collectd.conf(5)
AUTHOR
Florian Forster <octo at collectd.org>
5.11.0.94.g41b1e33 2020-07-20 COLLECTD-THRESHOLD(5)
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