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 it's 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), the threshold must be treated as interesting and, when a number of Timeout values will lost, then a
missing notification will be dispatched. On the other hand, if set to false, the missing notification will never dispatched for this
threshold.
SEE ALSO
collectd(1), collectd.conf(5)
AUTHOR
Florian Forster <octo at collectd.org>
5.1.0 2012-04-02 COLLECTD-THRESHOLD(5)