1SYSLOG-NG.CONF(5) The syslog-ng.conf manual page SYSLOG-NG.CONF(5)
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6 syslog-ng.conf - syslog-ng configuration file
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9 syslog-ng.conf
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12 This manual page is only an abstract, for the complete documentation of
13 syslog-ng, see The Administrator Guide[1] or the official syslog-ng
14 website[2].
15 The application is a flexible and highly scalable system logging
17 application. Typically, syslog-ng is used to manage log messages and
18 implement centralized logging, where the aim is to collect the log
19 messages of several devices on a single, central log server. The
20 different devices - called syslog-ng clients - all run syslog-ng, and
21 collect the log messages from the various applications, files, and
22 other sources. The clients send all important log messages to the
23 remote syslog-ng server, where the server sorts and stores them.
24
26 The syslog-ng application reads incoming messages and forwards them to
27 the selected destinations. The syslog-ng application can receive
28 messages from files, remote hosts, and other sources.
29 Log messages enter syslog-ng in one of the defined sources, and are
31 sent to one or more destinations.
32 Sources and destinations are independent objects, log paths define what
34 syslog-ng does with a message, connecting the sources to the
35 destinations. A log path consists of one or more sources and one or
36 more destinations: messages arriving from a source are sent to every
37 destination listed in the log path. A log path defined in syslog-ng is
38 called a log statement.
39 Optionally, log paths can include filters. Filters are rules that
41 select only certain messages, for example, selecting only messages sent
42 by a specific application. If a log path includes filters, syslog-ng
43 sends only the messages satisfying the filter rules to the destinations
44 set in the log path.
45 Other optional elements that can appear in log statements are parsers
47 and rewriting rules. Parsers segment messages into different fields to
48 help processing the messages, while rewrite rules modify the messages
49 by adding, replacing, or removing parts of the messages.
50
52 • The main body of the configuration file consists of object
53 definitions: sources, destinations, logpaths define which log
54 message are received and where they are sent. All identifiers,
55 option names and attributes, and any other strings used in the
56 syslog-ng configuration file are case sensitive. Object definitions
57 (also called statements) have the following syntax:
58 type-of-the-object identifier-of-the-object {<parameters>};
60 • Type of the object: One of source, destination, log, filter,
62 parser, rewrite rule, or template.
63 • Identifier of the object: A unique name identifying the object.
65 When using a reserved word as an identifier, enclose the
66 identifier in quotation marks.
67 All identifiers, attributes, and any other strings used in the
69 syslog-ng configuration file are case sensitive.
70 Tip
72 Use identifiers that refer to the type of the object they
73 identify. For example, prefix source objects with s_,
74 destinations with d_, and so on.
75 Note
77 Repeating a definition of an object (that is, defining the
78 same object with the same id more than once) is not
79 allowed, unless you use the @define allow-config-dups 1
80 definition in the configuration file.
81 • Parameters: The parameters of the object, enclosed in braces
83 {parameters}.
84 • Semicolon: Object definitions end with a semicolon (;).
86 For example, the following line defines a source and calls it
88 s_internal.
89 source s_internal { internal(); };
91 The object can be later referenced in other statements using its
93 ID, for example, the previous source is used as a parameter of the
94 following log statement:
95 log { source(s_internal); destination(d_file); };
97 • The parameters and options within a statement are similar to
99 function calls of the C programming language: the name of the
100 option followed by a list of its parameters enclosed within
101 brackets and terminated with a semicolon.
102 option(parameter1, parameter2); option2(parameter1, parameter2);
104 For example, the file() driver in the following source statement
106 has three options: the filename (/var/log/apache/access.log),
107 follow-freq(), and flags(). The follow-freq() option also has a
108 parameter, while the flags() option has two parameters.
109 source s_tail { file("/var/log/apache/access.log"
111 follow-freq(1) flags(no-parse, validate-utf8)); };
112 Objects may have required and optional parameters. Required
114 parameters are positional, meaning that they must be specified in a
115 defined order. Optional parameters can be specified in any order
116 using the option(value) format. If a parameter (optional or
117 required) is not specified, its default value is used. The
118 parameters and their default values are listed in the reference
119 section of the particular object.
120 Example 1. Using required and optional parameters The unix-stream()
122 source driver has a single required argument: the name of the
123 socket to listen on. Optional parameters follow the socket name in
124 any order, so the following source definitions have the same
125 effect:
126 source s_demo_stream1 {
128 unix-stream("<path-to-socket>" max-connections(10) group(log)); };
129 source s_demo_stream2 {
130 unix-stream("<path-to-socket>" group(log) max-connections(10)); };
131 • Some options are global options, or can be set globally, for
133 example, whether should use DNS resolution to resolve IP addresses.
134 Global options are detailed in ???.
135 options { use-dns(no); };
137 • Objects can be used before definition.
139 • Objects can be defined inline as well. This is useful if you use
141 the object only once (for example, a filter). For details, see ???.
142 • To add comments to the configuration file, start a line with # and
144 write your comments. These lines are ignored by syslog-ng.
145 # Comment: This is a stream source
147 source s_demo_stream {
148 unix-stream("<path-to-socket>" max-connections(10) group(log)); };
149 The syntax of log statements is as follows:
151 log {
153 source(s1); source(s2); ...
154 optional_element(filter1|parser1|rewrite1);
155 optional_element(filter2|parser2|rewrite2);
156 ...
157 destination(d1); destination(d2); ...
158 flags(flag1[, flag2...]);
159 };
160 The following log statement sends all messages arriving to the
162 localhost to a remote server.
163 source s_localhost { network(ip(127.0.0.1) port(1999)); };
165 destination d_tcp { network("10.1.2.3" port(1999) localport(999)); };
166 log { source(s_localhost); destination(d_tcp); };
167 The syslog-ng application has a number of global options governing DNS
169 usage, the timestamp format used, and other general points. Each option
170 may have parameters, similarly to driver specifications. To set global
171 options, add an option statement to the syslog-ng configuration file
172 using the following syntax:
173 options { option1(params); option2(params); ... };
175 Example 2. Using global options
177 To disable domain name resolving, add the following line to the
179 syslog-ng configuration file:
180 options { use-dns(no); };
182 The sources, destinations, and filters available in syslog-ng are
184 listed below. For details, see The syslog-ng Administrator Guide.
185 Table 1. Source drivers available in syslog-ng
187 ┌──────────────────┬────────────────────────────┐
188 │Name │ Description │
189 ├──────────────────┼────────────────────────────┤
190 │file() │ Opens the specified file │
191 │ │ and reads messages. │
192 ├──────────────────┼────────────────────────────┤
193 │internal() │ Messages generated │
194 │ │ internally in syslog-ng. │
195 ├──────────────────┼────────────────────────────┤
196 │network() │ Receives messages from │
197 │ │ remote hosts using the │
198 │ │ BSD-syslog protocol over │
199 │ │ IPv4 and IPv6. Supports │
200 │ │ the TCP, UDP, and TLS │
201 │ │ network protocols. │
202 ├──────────────────┼────────────────────────────┤
203 │pipe() │ Opens the specified named │
204 │ │ pipe and reads messages. │
205 ├──────────────────┼────────────────────────────┤
206 │program() │ Opens the specified │
207 │ │ application and reads │
208 │ │ messages from its standard │
209 │ │ output. │
210 ├──────────────────┼────────────────────────────┤
211 │sun-stream(), │ Opens the specified │
212 │sun-streams() │ STREAMS device on Solaris │
213 │ │ systems and reads incoming │
214 │ │ messages. │
215 ├──────────────────┼────────────────────────────┤
216 │syslog() │ Listens for incoming │
217 │ │ messages using the new │
218 │ │ IETF-standard syslog │
219 │ │ protocol. │
220 ├──────────────────┼────────────────────────────┤
221 │system() │ Automatically detects │
222 │ │ which platform is running │
223 │ │ on, and collects the │
224 │ │ native log messages of │
225 │ │ that platform. │
226 ├──────────────────┼────────────────────────────┤
227 │systemd-journal() │ Collects messages directly │
228 │ │ from the journal of │
229 │ │ platforms that use │
230 │ │ systemd. │
231 ├──────────────────┼────────────────────────────┤
232 │systemd-syslog() │ Collects messages from the │
233 │ │ journal using a socket on │
234 │ │ platforms that use │
235 │ │ systemd. │
236 ├──────────────────┼────────────────────────────┤
237 │unix-dgram() │ Opens the specified unix │
238 │ │ socket in SOCK_DGRAM mode │
239 │ │ and listens for incoming │
240 │ │ messages. │
241 ├──────────────────┼────────────────────────────┤
242 │unix-stream() │ Opens the specified unix │
243 │ │ socket in SOCK_STREAM mode │
244 │ │ and listens for incoming │
245 │ │ messages. │
246 └──────────────────┴────────────────────────────┘
247 Table 2. Destination drivers available in syslog-ng
249 ┌───────────────┬────────────────────────────┐
250 │Name │ Description │
251 ├───────────────┼────────────────────────────┤
252 │elasticsearch2 │ Sends messages to an │
253 │ │ Elasticsearch server. The │
254 │ │ elasticsearch2 driver │
255 │ │ supports Elasticsearch │
256 │ │ version 2 and newer. │
257 ├───────────────┼────────────────────────────┤
258 │file() │ Writes messages to the │
259 │ │ specified file. │
260 ├───────────────┼────────────────────────────┤
261 │hdfs() │ Sends messages into a file │
262 │ │ on a Hadoop Distributed │
263 │ │ File System (HDFS)[3] │
264 │ │ node. │
265 ├───────────────┼────────────────────────────┤
266 │kafka() │ Publishes log messages to │
267 │ │ the Apache Kafka[4] │
268 │ │ message bus, where │
269 │ │ subscribers can access │
270 │ │ them. │
271 ├───────────────┼────────────────────────────┤
272 │loggly() │ Sends log messages to the │
273 │ │ Loggly[5] │
274 │ │ Logging-as-a-Service │
275 │ │ provider. │
276 ├───────────────┼────────────────────────────┤
277 │logmatic() │ Sends log messages to the │
278 │ │ Logmatic.io[6] │
279 │ │ Logging-as-a-Service │
280 │ │ provider. │
281 ├───────────────┼────────────────────────────┤
282 │mongodb() │ Sends messages to a │
283 │ │ MongoDB[7] database. │
284 ├───────────────┼────────────────────────────┤
285 │network() │ Sends messages to a remote │
286 │ │ host using the BSD-syslog │
287 │ │ protocol over IPv4 and │
288 │ │ IPv6. Supports the TCP, │
289 │ │ UDP, and TLS network │
290 │ │ protocols. │
291 ├───────────────┼────────────────────────────┤
292 │pipe() │ Writes messages to the │
293 │ │ specified named pipe. │
294 ├───────────────┼────────────────────────────┤
295 │program() │ Forks and launches the │
296 │ │ specified program, and │
297 │ │ sends messages to its │
298 │ │ standard input. │
299 ├───────────────┼────────────────────────────┤
300 │sql() │ Sends messages into an SQL │
301 │ │ database. In addition to │
302 │ │ the standard syslog-ng │
303 │ │ packages, the sql() │
304 │ │ destination requires │
305 │ │ database-specific packages │
306 │ │ to be installed. Refer to │
307 │ │ the section appropriate │
308 │ │ for your platform in ???. │
309 ├───────────────┼────────────────────────────┤
310 │syslog() │ Sends messages to the │
311 │ │ specified remote host │
312 │ │ using the IETF-syslog │
313 │ │ protocol. The IETF │
314 │ │ standard supports message │
315 │ │ transport using the UDP, │
316 │ │ TCP, and TLS networking │
317 │ │ protocols. │
318 ├───────────────┼────────────────────────────┤
319 │unix-dgram() │ Sends messages to the │
320 │ │ specified unix socket in │
321 │ │ SOCK_DGRAM style (BSD). │
322 ├───────────────┼────────────────────────────┤
323 │unix-stream() │ Sends messages to the │
324 │ │ specified unix socket in │
325 │ │ SOCK_STREAM style (Linux). │
326 ├───────────────┼────────────────────────────┤
327 │usertty() │ Sends messages to the │
328 │ │ terminal of the specified │
329 │ │ user, if the user is │
330 │ │ logged in. │
331 └───────────────┴────────────────────────────┘
332 Table 3. Filter functions available in
334 ┌──────────────────────┬────────────────────────────┐
335 │Name │ Description │
336 ├──────────────────────┼────────────────────────────┤
337 │facility() │ Filter messages based on │
338 │ │ the sending facility. │
339 ├──────────────────────┼────────────────────────────┤
340 │filter() │ Call another filter │
341 │ │ function. │
342 ├──────────────────────┼────────────────────────────┤
343 │host() │ Filter messages based on │
344 │ │ the sending host. │
345 ├──────────────────────┼────────────────────────────┤
346 │inlist() │ File-based whitelisting │
347 │ │ and blacklisting. │
348 ├──────────────────────┼────────────────────────────┤
349 │level() or priority() │ Filter messages based on │
350 │ │ their priority. │
351 ├──────────────────────┼────────────────────────────┤
352 │match() │ Use a regular expression │
353 │ │ to filter messages based │
354 │ │ on a specified header or │
355 │ │ content field. │
356 ├──────────────────────┼────────────────────────────┤
357 │message() │ Use a regular expression │
358 │ │ to filter messages based │
359 │ │ on their content. │
360 ├──────────────────────┼────────────────────────────┤
361 │netmask() │ Filter messages based on │
362 │ │ the IP address of the │
363 │ │ sending host. │
364 ├──────────────────────┼────────────────────────────┤
365 │program() │ Filter messages based on │
366 │ │ the sending application. │
367 ├──────────────────────┼────────────────────────────┤
368 │source() │ Select messages of the │
369 │ │ specified source │
370 │ │ statement. │
371 ├──────────────────────┼────────────────────────────┤
372 │tags() │ Select messages having the │
373 │ │ specified tag. │
374 └──────────────────────┴────────────────────────────┘
375
377 /usr/local/
378 /usr/local/etc/syslog-ng.conf
380
382 syslog-ng(8)
383 Note
385 For the detailed documentation of see The 3.30 Administrator
386 Guide[8]
387 If you experience any problems or need help with syslog-ng, visit
389 the syslog-ng mailing list[9].
390 For news and notifications about of syslog-ng, visit the syslog-ng
392 blogs[10].
393
395 This manual page was written by the Balabit Documentation Team
396 <documentation@balabit.com>.
397
400 1. The Administrator Guide
401 https://www.balabit.com/support/documentation/
402 2. the official syslog-ng website
404 https://www.balabit.com/log-management
405 3. Hadoop Distributed File System (HDFS)
407 http://hadoop.apache.org/
408 4. Apache Kafka
410 http://kafka.apache.org
411 5. Loggly
413 https://www.loggly.com/
414 6. Logmatic.io
416 https://logmatic.io/
417 7. MongoDB
419 https://www.mongodb.com
420 8. The 3.30 Administrator Guide
422 https://www.balabit.com/documents/syslog-ng-ose-latest-guides/en/syslog-ng-ose-guide-admin/html/index.html
423 9. syslog-ng mailing list
425 https://lists.balabit.hu/mailman/listinfo/syslog-ng
426 10. syslog-ng blogs
428 https://syslog-ng.org/blogs/
4293.30 11/18/2020 SYSLOG-NG.CONF(5)