1PMDASTATSD(1) General Commands Manual PMDASTATSD(1)
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6 pmdastatsd - StatsD protocol performance metric domain agent (PMDA)
7
9 $PCP_PMDAS_DIR/statsd/pmdastatsd [-Z maximum udp packet size] [-P port]
10 [-v] [-g] [-o debug output filename] [-s] [-r parser type] [-a port]
11 [-z maximum of unprocessed packets]
12
14 StatsD is simple, text-based UDP protocol for receiving monitoring data
15 of applications in architecture client-server. pmdastatsd is an Per‐
16 formance Metrics Domain Agent that collects StatsD data, aggregates
17 them and makes them available to any Performance Co-Pilot client, which
18 is ideal for easily tracking stats in your application.
19 The statsd PMDA supports Counter, Gauge and Duration (with instances
21 for minimum, maximum, median, average, 90th percentile, 95th per‐
22 centile, 99th percentile, count and standard deviation) metric types,
23 offers multiple parsing options: Ragel or handwritten/custom parser,
24 offers multiple aggregating options for duration metric type: basic
25 histogram or HDR histogram, supports custom form of labels, logging,
26 exports multiple metrics about itself and may be configured either with
27 an ini file or command line options.
28
30 A brief description of the pmdastatsd command line options follows:
31 -Z, --max-udp=<value>
33 Maximum allowed packet size, any larger then this will be thrown
34 away. Default: 1472
35 -P, --port=<value>
37 Which port agent will listen to for incoming trafic. Default:
38 8125
39 -v, --verbose
41 Verbosity level. Prints info about agent execution into logfile.
42 Valid values are 0-2. 0 = Default value, shows config information,
43 read socket state, and first 100 dropped messages. 1 = Shows PMNS
44 and related information. 2 = Most detailed verbosity level, also
45 shows dropped messages above 100. All levels include those be‐
46 lows.
47 -o, --debug-output-filename=<value>
49 You can send USR1 signal that 'asks' agent to output basic infor‐
50 mation about all aggregated metric into a
51 $PCP_LOG_DIR/pmcd/statsd_{name} file. Default: 0
52 -s, --version
54 Flag controlling whether or not to log current agent version on
55 start. Default: 0
56 -p, --parser-type=<value>
58 Flag specifying which parser to use for incoming packets; Basic =
59 0, Ragel = 1. Default: 0
60 -a, --duration-aggregation-type=<value>
62 Flag specifying which aggregation scheme to use for duration met‐
63 rics; basic histogram = 0, HDR histogram = 1. Default: 1
64 -z, -max-unprocessed-packets=<value>
66 Maximum size of packet queue that the agent will save in memory.
67 There are 2 queues: one for packets that are waiting to be parsed
68 and one for parsed packets before they are aggregated. Default:
69 2048
70 The agent also looks for a pmdastatsd.ini file in the $PCP_PM‐
72 DAS_DIR/statsd directory. There, the same options may be specified,
73 albeit with slightly different names as follows:
74 max_udp_packet_size=<value>
76 port=<value>
77 verbose=<value>
78 debug=<value>
79 debug_output_filename=<value>
80 version=<value>
81 parser_type=<value>
82 duration_aggregation_type=<value>
83 max_unprocessed_packets=<value>
84 Should an option be specified in both pmdastatsd.ini and command line,
86 then the latter takes precedence. Most of the time you will want to
87 configure the agent with an ini file, as the agent should never be exe‐
88 cuted directly.
89 Location of the log file. By default, a log file named statsd.log is
91 written in the current directory of pmcd(1) when pmdastatsd is started,
92 i.e. $PCP_LOG_DIR/pmcd. If the log file cannot be created or is not
93 writable, output is written to standard error instead.
94
96 If you want to install the pmdastatsd, do the following as root:
97 # cd $PCP_PMDAS_DIR/statsd
99 # ./Install
100 To uninstall, do the following as root:
102 # cd $PCP_PMDAS_DIR/statsd
104 # ./Remove
105 pmdastatsd is launched by pmcd(1) and should never be executed di‐
107 rectly. The Install and Remove scripts notify pmcd(1) when the agent
108 is installed or removed.
109
111 Once started, pmdastatsd will listen on specified port for any content
112 in a form of:
113 <metricname>:<value>|<type>
115 There may be multiple such messages in single datagram, split by a new‐
117 line character, so this:
118 <metricname>:<value>|<type>\n<metricname>:<value>|<type>
120 is valid as well. Constraints for each of the above variables are:
122 <metricname> = [a-z][a-zA-Z0-9_.]*
124 <value> = described further in each metric type subsection
125 <type> = One of the following: c , g or ms
126 If verbose logging is turned on, agent will log every message parsed
128 and related failures.
129 All recorded metrics will, if parsed and aggregated successfully, be
131 made available under statsd.* namespace.
132 1 Counter metric
134 Stores metrics as simple counters, adding any incoming values to al‐
135 ready existing ones.
136 <metricname>:<value>|c
138 Where value is positive number.
140 Example:
142 After aggregating following messages:
144 metric:20|c
146 metric:10|c
147 metric:3.3|c
148 Value available to PCP will be:
150 # pminfo --fetch statsd.metric
152 inst [0 or '/'] value 33.3
154 2 Gauge metric
156 Stores metrics as modifiable values, with an option to either set, in‐
157 crement or decrement values.
158 <metricname>:<value>|g
160 Where value can be in a form of:
162 '-{value}', when negative value is supplied agent will substract
164 value stored with the value passed
165 '+{value}', when positive value with a leading plus sign is sup‐
167 plied, the agent will add the passed value to the value stored
168 '{value}', when a value without any leading sign is supplied, the
170 agent will set the metric to the passed value.
171 Initial value for metric of gauge type is 0.
173 Example:
175 After aggregating following messages:
177 metric:20|g
179 metric:+10|g
180 metric:-3.3|g
181 Value available to PCP will be:
183 # pminfo --fetch statsd.metric
185 inst [0 or '/'] value 26.7
187 3 Duration metric
189 Aggregates values either via HDR histogram or simply stores all values
190 and then calculates instances from all values received.
191 <metricname>:<value>|ms
193 Where value is a positive number.
195 Example:
197 With larger message count, the values may vary based on selected dura‐
199 tion aggregation scheme.
200 After aggregating following messages:
202 metric:10|ms
204 metric:20|ms
205 Values available to PCP will be:
207 # pminfo --fetch statsd.metric
209 inst[0 or '/min'] value 10
211 inst[1 or '/max'] value 20
212 inst[2 or '/median'] value 10
213 inst[3 or '/average'] value 15
214 inst[4 or '/percentile90'] value 20
215 inst[5 or '/percentile95'] value 20
216 inst[6 or '/percentile99'] value 20
217 inst[7 or '/count'] value 2
218 inst[8 or '/std_deviation'] value 5
219 Note:
221 Once you send given metricname with specified type, the agent will no
223 longer aggregate any messages with same. metricname but different type
224 and will throw them away.
225 4 Labels
227 StatsD datagrams may also contain key:value pairs separated by commas
228 like so:
229 metric,tagX=X,tagW=W:5|c
231 OR
233 metric:5|ms|#tagX:X,tagW:W
235 Where tagX is a key, X is a value and tagW is a key, W is a value.
237 Both key and value of such a pair are [a-ZA-Z0-9_.]{1,}.
239 Both formats are interchangeable and you may combine them together.
241 When key is not unique, right most value takes precendence. This is
242 valid:
243 metric,tagX=1:5|c|#tagX:2
245 Pair with key tagX will have value of 2.
247 You may use these labels to map specific values to some PCP instances.
249 PCP labels are also assigned to these PCP instances. Pairs are ordered
250 by key in resulting instance name and label descriptor.
251 Single label:
253 metric,tagX=X:5|c
255 Such a payload would map to PCP as follows (non-related labels were om‐
257 mited):
258 # pminfo --fetch --labels statsd.metric
260 inst [0 or '/tagX=X'] value 5
262 inst [0 or '/tagX=X'] labels {'tagX':'X'}
263 As shown earlier you may also send payload with multiple labels. When
265 multiple labels are supplied they are split in instance name by '::'.
266 Example:
267 metric,tagX=X,tagW=W:5|c
269 This resolves to:
271 # pminfo --fetch --labels statsd.metric
273 inst [0 or '/tagX=X::tagW=W'] value 5
275 inst [0 or '/tagX=X::tagW=W'] labels {'tagX':'X','tagW':'W'}
276 Note:
278 Be mindful of the fact that duration metric type already maps to in‐
280 stances even without any labels. Sending labeled value to such a met‐
281 ric creates another 9 (as there are that many hardcoded) instances.
282 Example:
284 metric:200|ms
286 metric:100|ms
287 metric,target=cpu2:10|ms
288 metric,target=cpu2:100|ms
289 metric,target=cpu2:1000|ms
290 Creates 18 instances. Duration data type and label name compose in‐
292 stance name in following manner:
293 # pminfo --fetch --labels statsd.metric
295 ...
297 inst [10 or '/max::target=cpu0'] value 1000
298 inst [10 or '/max::target=cpu0'] labels {'target':'cpu0'}
299 ...
300 5 Hardcoded stats
302 Agent also exports metrics about itself:
303 statsd.pmda.received
305 Number of datagrams that the agent has received
306 statsd.pmda.parsed
308 Number of datagrams that were successfully parsed
309 statsd.pmda.dropped
311 Number of datagrams that were dropped
312 statsd.pmda.aggregated
314 Number of datagrams that were aggregated
315 statsd.pmda.metrics_tracked
317 This metric has 3 instances. counter - Number of tracked counter
318 metrics. gauge - Number of tracked gauge metrics. duration -
319 Number of tracked duration metrics. total - Number of tracked
320 metrics total.
321 statsd.pmda.time_spent_parsing
323 Total time in microseconds spent parsing metrics. Includes time
324 spent parsing a datagram and failing midway.
325 statsd.pmda.time_spent_aggregating
327 Total time in microseconds spent aggregating metrics. Includes
328 time spent aggregating a metric and failing midway.
329 statsd.pmda.settings.max_udp_packet_size
331 Maximum UDP packet size
332 statsd.pmda.settings.max_unprocessed_packets
334 Maximum size of unprocessed packets Q
335 statsd.pmda.settings.verbose
337 Verbosity flag
338 statsd.pmda.settings.debug_output_filename
340 Debug output filename
341 statsd.pmda.settings.port
343 Port that is listened to
344 statsd.pmda.settings.parser_type
346 Used parser type
347 statsd.pmda.settings.duration_aggregation_type
349 Used duration aggregation type
350 These names are blocklisted for user usage. No messages with these
352 names will processed. While not yet reserved, the whole statsd.pmda.*
353 namespace is not recommended to use for user metrics.
354
356 $PCP_PMCDCONF_PATH
357 command line options used to launch pmdastatsd
358 $PCP_PMDAS_DIR/statsd/Install
359 installation script for the pmdastatsd agent
360 $PCP_PMDAS_DIR/statsd/Remove
361 undo installation script for the pmdastatsd agent
362 $PCP_LOG_DIR/pmcd/statsd.log
363 default log file for error messages and other information
364 from pmdastatsd
365
367 Environment variables with the prefix PCP_ are used to parameterize the
368 file and directory names used by PCP. On each installation, the file
369 /etc/pcp.conf contains the local values for these variables. The
370 $PCP_CONF variable may be used to specify an alternative configuration
371 file, as described in pcp.conf(5).
372
374 PCPIntro(1), pmcd(1), pcp.conf(5) and pcp.env(5).
375Performance Co-Pilot PCP PMDASTATSD(1)