StatsD is a system to collect data from any application. Applications send metrics to it, usually via non-blocking UDP communication, and StatsD servers collect these metrics, perform a few simple calculations on them and push them to backend time-series databases.
If you want to learn more about the StatsD protocol, we have written a blog post about it!
Netdata is a fully featured statsd server. It can collect statsd formatted metrics, visualize them on its dashboards and store them in it's database for long-term retention.
Netdata statsd is inside Netdata (an internal plugin, running inside the Netdata daemon), it is configured via netdata.conf
and by-default listens on standard statsd port 8125. Netdata supports both tcp and udp packets at the same time.
Since statsd is embedded in Netdata, it means you now have a statsd server embedded on all your servers.
Netdata statsd is fast. It can collect more than 1.200.000 metrics per second on modern hardware, more than 200Mbps of sustained statsd traffic, using 1 CPU core. The implementation uses two threads: one thread collects metrics, another one updates the charts from the collected data.
Netdata ships with collectors implemented using the StatsD collector. They are configuration files (as you will read below), but they function as a collector, in the sense that configuration file organize the metrics of a data source into pre-defined charts.
On these charts, we can have alarms as with any metric and chart.
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Netdata fully supports the StatsD protocol. All StatsD client libraries can be used with Netdata too.
-
Gauges
The application sends
name:value|g
, wherevalue
is any decimal/fractional number, StatsD reports the latest value collected and the number of times it was updated (events).The application may increment or decrement a previous value, by setting the first character of the value to
+
or-
(so, the only way to set a gauge to an absolute negative value, is to first set it to zero).Sampling rate is supported.
When a gauge is not collected and the setting is not to show gaps on the charts (the default), the last value will be shown, until a data collection event changes it.
-
Counters and Meters
The application sends
name:value|c
,name:value|C
orname:value|m
, wherevalue
is a positive or negative integer number of events occurred, StatsD reports the rate and the number of times it was updated (events).:value
can be omitted and StatsD will assume it is1
.|c
,|C
and|m
can be omitted an StatsD will assume it is|m
. So, the application may send justname
and StatsD will parse it asname:1|m
.- Counters use
|c
(etsy/StatsD compatible) or|C
(brubeck compatible) - Meters use
|m
Sampling rate is supported.
When a counter or meter is not collected, Netdata defaults to showing a zero value, until a data collection event changes the value.
- Counters use
-
Timers and Histograms
The application sends
name:value|ms
orname:value|h
, wherevalue
is any decimal/fractional number, StatsD reports min, max, average, sum, 95th percentile, median and standard deviation and the total number of times it was updated (events).- Timers use
|ms
- Histograms use
|h
The only difference between the two, is the
units
of the charts, as timers report milliseconds.Sampling rate is supported.
When a counter or meter is not collected, Netdata defaults to showing a zero value, until a data collection event changes the value.
- Timers use
-
Sets
The application sends
name:value|s
, wherevalue
is anything (number or text, leading and trailing spaces are removed), StatsD reports the number of unique values sent and the number of times it was updated (events).Sampling rate is not supported for Sets.
value
is always considered text.When a counter or meter is not collected, Netdata defaults to showing a zero value, until a data collection event changes the value.
The application may append |@sampling_rate
, where sampling_rate
is a number from 0.0
to 1.0
in order for StatD to extrapolate the value and predict the total for the entire period. If the application reports to StatsD a value for 1/10th of the time, it can append |@0.1
to the metrics it sends to statsd.
Netdata's StatsD server maintains different indexes for each of the types supported. This means the same metric name
may exist under different types concurrently.
Netdata accepts multiple metrics per packet if each is terminated with \n
.
Netdata listens for both TCP and UDP packets. For TCP, is it important to always append \n
on each metric, as Netdata will use the newline character to detect if a metric is split into multiple TCP packets.
On disconnect, Netdata will process the entire buffer, even if it is not terminated with a \n
.
When sending multiple packets over UDP, it is important not to exceed the network MTU, which is usually 1500 bytes.
Netdata will accept UDP packets up to 9000 bytes, but the underlying network will not exceed MTU.
You can read more about the network maximum transmission unit(MTU) in this cloudflare article.
You can find the configuration at /etc/netdata/netdata.conf
:
[statsd]
# enabled = yes
# decimal detail = 1000
# update every (flushInterval) = 1
# udp messages to process at once = 10
# create private charts for metrics matching = *
# max private charts allowed = 200
# max private charts hard limit = 1000
# private charts memory mode = save
# private charts history = 3996
# histograms and timers percentile (percentThreshold) = 95.00000
# add dimension for number of events received = yes
# gaps on gauges (deleteGauges) = no
# gaps on counters (deleteCounters) = no
# gaps on meters (deleteMeters) = no
# gaps on sets (deleteSets) = no
# gaps on histograms (deleteHistograms) = no
# gaps on timers (deleteTimers) = no
# listen backlog = 4096
# default port = 8125
# bind to = udp:localhost:8125 tcp:localhost:8125
-
enabled = yes|no
controls if StatsD will be enabled for this Netdata. The default is enabled.
-
default port = 8125
controls the default port StatsD will use if no port is defined in the following setting.
-
bind to = udp:localhost tcp:localhost
is a space separated list of IPs and ports to listen to. The format is
PROTOCOL:IP:PORT
- ifPORT
is omitted, thedefault port
will be used. IfIP
is IPv6, it needs to be enclosed in[]
.IP
can also be*
(to listen on all IPs) or even a hostname. -
update every (flushInterval) = 1
seconds, controls the frequency StatsD will push the collected metrics to Netdata charts. -
decimal detail = 1000
controls the number of fractional digits in gauges and histograms. Netdata collects metrics using signed 64 bit integers and their fractional detail is controlled using multipliers and divisors. This setting is used to multiply all collected values to convert them to integers and is also set as the divisors, so that the final data will be a floating point number with this fractional detail (1000 = X.0 - X.999, 10000 = X.0 - X.9999, etc).
The rest of the settings are discussed below.
Netdata can visualize StatsD collected metrics in 2 ways:
-
Each metric gets its own private chart. This is the default and does not require any configuration. You can adjust the default parameters.
-
Synthetic charts can be created, combining multiple metrics, independently of their metric types. For this type of charts, special configuration is required, to define the chart title, type, units, its dimensions, etc.
Private charts are controlled with create private charts for metrics matching = *
. This setting accepts a space-separated list of simple patterns. Netdata will create private charts for all metrics by default.
For example, to render charts for all myapp.*
metrics, except myapp.*.badmetric
, use:
create private charts for metrics matching = !myapp.*.badmetric myapp.*
You can specify Netdata StatsD to have a different memory mode
than the rest of the Netdata Agent. You can read more about memory mode
in the documentation.
The default behavior is to use the same settings as the rest of the Netdata Agent. If you wish to change them, edit the following settings:
private charts memory mode
private charts history
If you have thousands of metrics, each with its own private chart, you may notice that your web browser becomes slow when you view the Netdata dashboard (this is a web browser issue we need to address at the Netdata UI). So, Netdata has a protection to stop creating charts when max private charts allowed = 200
(soft limit) is reached.
The metrics above this soft limit are still processed by Netdata and will be available to be sent to backend time-series databases, up to max private charts hard limit = 1000
. So, between 200 and 1000 charts, Netdata will still generate charts, but they will automatically be created with memory mode = none
(Netdata will not maintain a database for them). These metrics will be sent to backend time series databases, if the backend configuration is set to as collected
.
Metrics above the hard limit are still collected, but they can only be used in synthetic charts (once a metric is added to chart, it will be sent to backend servers too).
Example private charts (automatically generated without any configuration):
- Scope: count the events of something (e.g. number of file downloads)
- Format:
name:INTEGER|c
orname:INTEGER|C
orname|c
- StatsD increments the counter by the
INTEGER
number supplied (positive, or negative).
- Scope: report the value of something (e.g. cache memory used by the application server)
- Format:
name:FLOAT|g
- StatsD remembers the last value supplied, and can increment or decrement the latest value if
FLOAT
begins with+
or-
.
- Scope: statistics on a size of events (e.g. statistics on the sizes of files downloaded)
- Format:
name:FLOAT|h
- StatsD maintains a list of all the values supplied and provides statistics on them.
The same chart with sum
unselected, to show the detail of the dimensions supported:
This is identical to counter
.
- Scope: count the events of something (e.g. number of file downloads)
- Format:
name:INTEGER|m
orname|m
or justname
- StatsD increments the counter by the
INTEGER
number supplied (positive, or negative).
- Scope: count the unique occurrences of something (e.g. unique filenames downloaded, or unique users that downloaded files)
- Format:
name:TEXT|s
- StatsD maintains a unique index of all values supplied, and reports the unique entries in it.
- Scope: statistics on the duration of events (e.g. statistics for the duration of file downloads)
- Format:
name:FLOAT|ms
- StatsD maintains a list of all the values supplied and provides statistics on them.
The same chart with the sum
unselected:
Use synthetic charts to create dedicated sections on the dashboard to render your StatsD charts.
Synthetic charts are organized in
- application aka section in Netdata Dashboard.
- charts for each application aka family in Netdata Dashboard.
- StatsD metrics for each chart /aka charts and context Netdata Dashboard.
You can read more about how the Netdata Agent organizes information in the relevant documentation
For each application you need to create a .conf
file in /etc/netdata/statsd.d
.
For example, if you want to monitor the application myapp
using StatsD and Netdata, create the file /etc/netdata/statsd.d/myapp.conf
, with this content:
[app]
name = myapp
metrics = myapp.*
private charts = no
gaps when not collected = no
history = 60
# memory mode = ram
[dictionary]
m1 = metric1
m2 = metric2
# replace 'mychart' with the chart id
# the chart will be named: myapp.mychart
[mychart]
name = mychart
title = my chart title
family = my family
context = chart.context
units = tests/s
priority = 91000
type = area
dimension = myapp.metric1 m1
dimension = myapp.metric2 m2
Using the above configuration myapp
should get its own section on the dashboard, having one chart with 2 dimensions.
[app]
starts a new application definition. The supported settings in this section are:
-
name
defines the name of the app. -
metrics
is a Netdata simple pattern. This pattern should match all the possible StatsD metrics that will be participating in the applicationmyapp
. -
private charts = yes|no
, enables or disables private charts for the metrics matched. -
gaps when not collected = yes|no
, enables or disables gaps on the charts of the application in case that no metrics are collected. -
memory mode
sets the memory mode for all charts of the application. The default is the global default for Netdata (not the global default for StatsD private charts). We suggest not to use this (we have commented it out in the example) and let your app use the global default for Netdata, which is our dbengine. -
history
sets the size of the round robin database for this application. The default is the global default for Netdata (not the global default for StatsD private charts). This is only relevant if you usememory mode = save
. Read more on our [metrics storage(]/docs/store/change-metrics-storage.md) doc.
[dictionary]
defines name-value associations. These are used to renaming metrics, when added to synthetic charts. Metric names are also defined at each dimension
line. However, using the dictionary dimension names can be declared globally, for each app and is the only way to rename dimensions when using patterns. Of course the dictionary can be empty or missing.
Then, add any number of charts. Each chart should start with [id]
. The chart will be called app_name.id
. family
controls the submenu on the dashboard. context
controls the alarm templates. priority
controls the ordering of the charts on the dashboard. The rest of the settings are informational.
Add any number of metrics to a chart, using dimension
lines. These lines accept 5 space separated parameters:
- the metric name, as it is collected (it has to be matched by the
metrics =
pattern of the app) - the dimension name, as it should be shown on the chart
- an optional selector (type) of the value to shown (see below)
- an optional multiplier
- an optional divider
- optional flags, space separated and enclosed in quotes. All the external plugins
DIMENSION
flags can be used. Currently the only usable flag ishidden
, to add the dimension, but not show it on the dashboard. This is usually needed to have the values available for percentage calculation, or use them in alarms.
So, the format is this:
dimension = [pattern] METRIC NAME TYPE MULTIPLIER DIVIDER OPTIONS
pattern
is a keyword. When set, METRIC
is expected to be a Netdata simple pattern that will be used to match all the StatsD metrics to be added to the chart. So, pattern
automatically matches any number of StatsD metrics, all of which will be added as separate chart dimensions.
TYPE
, MULTIPLIER
, DIVIDER
and OPTIONS
are optional.
TYPE
can be:
events
to show the number of events received by StatsD for this metriclast
to show the last value, as calculated at the flush interval of the metric (the default)
Then for histograms and timers the following types are also supported:
min
, show the minimum valuemax
, show the maximum valuesum
, show the sum of all valuesaverage
(same aslast
)percentile
, show the 95th percentile (or any other percentile, as configured at StatsD global config)median
, show the median of all values (i.e. sort all values and get the middle value)stddev
, show the standard deviation of the values
StatsD metrics: foo
and bar
.
Contents of file /etc/netdata/stats.d/foobar.conf
:
[app]
name = foobarapp
metrics = foo bar
private charts = yes
[foobar_chart1]
title = Hey, foo and bar together
family = foobar_family
context = foobarapp.foobars
units = foobars
type = area
dimension = foo 'foo me' last 1 1
dimension = bar 'bar me' last 1 1
Metrics sent to statsd: foo:10|g
and bar:20|g
.
Private charts:
Synthetic chart:
You can define a dictionary to rename metrics sent by StatsD clients. This enables you to send response "200"
and Netdata visualize it as succesful connection
The [dictionary]
section accepts any number of name = value
pairs.
Netdata uses this dictionary as follows:
-
When a
dimension
has a non-emptyNAME
, that name is looked up at the dictionary. -
If the above lookup gives nothing, or the
dimension
has an emptyNAME
, the original StatsD metric name is looked up at the dictionary. -
If any of the above succeeds, Netdata uses the
value
of the dictionary, to set the name of the dimension. The dimensions will have as ID the original StatsD metric name, and as name, the dictionary value.
Use the dictionary in 2 ways:
- set
dimension = myapp.metric1 ''
and have at the dictionarymyapp.metric1 = metric1 name
- set
dimension = myapp.metric1 'm1'
and have at the dictionarym1 = metric1 name
In both cases, the dimension will be added with ID myapp.metric1
and will be named metric1 name
. So, in alarms use either of the 2 as ${myapp.metric1}
or ${metric1 name}
.
keep in mind that if you add multiple times the same StatsD metric to a chart, Netdata will append
TYPE
to the dimension ID, somyapp.metric1
will be added asmyapp.metric1_last
ormyapp.metric1_events
, etc. If you add multiple times the same metric with the sameTYPE
to a chart, Netdata will also append an incremental counter to the dimension ID, i.e.myapp.metric1_last1
,myapp.metric1_last2
, etc.
Netdata allows adding multiple dimensions to a chart, by matching the StatsD metrics with a Netdata simple pattern.
Assume we have an API that provides StatsD metrics for each response code per method it supports, like these:
myapp.api.get.200
myapp.api.get.400
myapp.api.get.500
myapp.api.del.200
myapp.api.del.400
myapp.api.del.500
myapp.api.post.200
myapp.api.post.400
myapp.api.post.500
myapp.api.all.200
myapp.api.all.400
myapp.api.all.500
In order to add all the response codes of myapp.api.get
to a chart, we simply make the following configuration:
[api_get_responses]
...
dimension = pattern 'myapp.api.get.* '' last 1 1
The above will add dimension named 200
, 400
and 500
. Netdata extracts the wildcard part of the metric name - so the dimensions will be named with whatever the *
matched.
You can rename the dimensions with this:
[dictionary]
get.200 = 200 ok
get.400 = 400 bad request
get.500 = 500 cannot connect to db
[api_get_responses]
...
dimension = pattern 'myapp.api.get.* 'get.' last 1 1
Note that we added a NAME
to the dimension line with get.
. This is prefixed to the wildcarded part of the metric name, to compose the key for looking up the dictionary. So 500
became get.500
which was looked up to the dictionary to find value 500 cannot connect to db
. This way we can have different dimension names, for each of the API methods (i.e. get.500 = 500 cannot connect to db
while post.500 = 500 cannot write to disk
).
To add all API methods to a chart, you can do this:
[ok_by_method]
...
dimension = pattern 'myapp.api.*.200 '' last 1 1
The above will add get
, post
, del
and all
to the chart.
If all
is not wanted (a stacked
chart does not need the all
dimension, since the sum of the dimensions provides the total), the line should be:
[ok_by_method]
...
dimension = pattern '!myapp.api.all.* myapp.api.*.200 '' last 1 1
With the above, all methods except all
will be added to the chart.
To automatically rename the methods, you can use this:
[dictionary]
method.get = GET
method.post = ADD
method.del = DELETE
[ok_by_method]
...
dimension = pattern '!myapp.api.all.* myapp.api.*.200 'method.' last 1 1
Using the above, the dimensions will be added as GET
, ADD
and DELETE
.
It's really easy to instrument your python application with StatsD, for example using jsocol/pystatsd.
import statsd
c = statsd.StatsClient('localhost', 8125)
c.incr('foo') # Increment the 'foo' counter.
for i in range(100000000):
c.incr('bar')
c.incr('foo')
if i % 3:
c.decr('bar')
c.timing('stats.timed', 320) # Record a 320ms 'stats.timed'.
You can find detailed documentation in their documentation page.
Using the client library by sivy/node-statsd, you can easily embed StatsD into your Node.js project.
var StatsD = require('node-statsd'),
client = new StatsD();
// Timing: sends a timing command with the specified milliseconds
client.timing('response_time', 42);
// Increment: Increments a stat by a value (default is 1)
client.increment('my_counter');
// Decrement: Decrements a stat by a value (default is -1)
client.decrement('my_counter');
// Using the callback
client.set(['foo', 'bar'], 42, function(error, bytes){
//this only gets called once after all messages have been sent
if(error){
console.error('Oh noes! There was an error:', error);
} else {
console.log('Successfully sent', bytes, 'bytes');
}
});
// Sampling, tags and callback are optional and could be used in any combination
client.histogram('my_histogram', 42, 0.25); // 25% Sample Rate
client.histogram('my_histogram', 42, ['tag']); // User-defined tag
client.histogram('my_histogram', 42, next); // Callback
client.histogram('my_histogram', 42, 0.25, ['tag']);
client.histogram('my_histogram', 42, 0.25, next);
client.histogram('my_histogram', 42, ['tag'], next);
client.histogram('my_histogram', 42, 0.25, ['tag'], next);
You can also use StatsD with:
- Golang, thanks to alexcesaro/statsd
- Ruby, thanks to reinh/statsd
- Java, thanks to DataDog/java-dogstatsd-client
Getting the proper support for a programming language is not always easy, but the Unix shell is available on most Unix systems. You can use shell and nc
to instrument your systems and send metric data to Netdata's StatsD implementation. Here's how:
The command you need to run is:
echo "NAME:VALUE|TYPE" | nc -u --send-only localhost 8125
Where:
NAME
is the metric nameVALUE
is the value for that metric (gauges|g
, timers|ms
and histograms|h
accept decimal/fractional numbers, counters|c
and meters|m
accept integers, sets|s
accept anything)TYPE
is one ofg
,ms
,h
,c
,m
,s
to select the metric type.
So, to set metric1
as gauge to value 10
, use:
echo "metric1:10|g" | nc -u --send-only localhost 8125
To increment metric2
by 10
, as a counter, use:
echo "metric2:10|c" | nc -u --send-only localhost 8125
You can send multiple metrics like this:
# send multiple metrics via UDP
printf "metric1:10|g\nmetric2:10|c\n" | nc -u --send-only localhost 8125
Remember, for UDP communication each packet should not exceed the MTU. So, if you plan to push too many metrics at once, prefer TCP communication:
# send multiple metrics via TCP
printf "metric1:10|g\nmetric2:10|c\n" | nc --send-only localhost 8125
You can also use this little function to take care of all the details:
#!/usr/bin/env bash
STATSD_HOST="localhost"
STATSD_PORT="8125"
statsd() {
local udp="-u" all="${*}"
# if the string length of all parameters given is above 1000, use TCP
[ "${#all}" -gt 1000 ] && udp=
while [ ! -z "${1}" ]
do
printf "${1}\n"
shift
done | nc ${udp} --send-only ${STATSD_HOST} ${STATSD_PORT} || return 1
return 0
}
You can use it like this:
# first, source it in your script
source statsd.sh
# then, at any point:
StatsD "metric1:10|g" "metric2:10|c" ...
The function is smart enough to call nc
just once and pass all the metrics to it. It will also automatically switch to TCP if the metrics to send are above 1000 bytes.
If you have gotten thus far, make sure to check out our community forums to share your experience using Netdata with StatsD.