line which sets this option, though, so that default installations will have
this setting enabled.
+=item B<PreCacheChain> I<ChainName>
+
+=item B<PostCacheChain> I<ChainName>
+
+Configure the name of the "pre-cache chain" and the "post-cache chain". Please
+see L<FILTER CONFIGURATION> below on information on chains and how these
+setting change the daemon's behavior.
+
=back
=head1 PLUGIN OPTIONS
=back
+=head2 Plugin C<bind>
+
+Starting with BIND 9.5.0, the most widely used DNS server software provides
+extensive statistics about queries, responses and lots of other information.
+The bind plugin retrieves this information that's encoded in XML and provided
+via HTTP and submits the values to collectd.
+
+To use this plugin, you first need to tell BIND to make this information
+available. This is done with the C<statistics-channels> configuration option:
+
+ statistics-channels {
+ inet localhost port 8053;
+ };
+
+The configuration follows the grouping that can be seen when looking at the
+data with an XSLT compatible viewer, such as a modern web browser. It's
+probably a good idea to make yourself familiar with the provided values, so you
+can understand what the collected statistics actually mean.
+
+Synopsis:
+
+ <Plugin "bind">
+ URL "http://localhost:8053/"
+ OpCodes true
+ QTypes true
+
+ ServerStats true
+ ZoneMaintStats true
+ ResolverStats false
+ MemoryStats true
+
+ <View "_default">
+ QTypes true
+ ResolverStats true
+ CacheRRSets true
+
+ Zone "127.in-addr.arpa/IN"
+ </View>
+ </Plugin>
+
+The bind plugin accepts the following configuration options:
+
+=over 4
+
+=item B<URL> I<URL>
+
+URL from which to retrieve the XML data. If not specified,
+C<http://localhost:8053/> will be used.
+
+=item B<OpCodes> I<true>|I<false>
+
+When enabled, statistics about the I<"OpCodes">, for example the number of
+C<QUERY> packets, are collected.
+
+Default: Enabled.
+
+=item B<QTypes> I<true>|I<false>
+
+When enabled, the number of I<incoming> queries by query types (for example
+C<A>, C<MX>, C<AAAA>) is collected.
+
+Default: Enabled.
+
+=item B<ServerStats> I<true>|I<false>
+
+Collect global server statistics, such as requests received over IPv4 and IPv6,
+successful queries, and failed updates.
+
+Default: Enabled.
+
+=item B<ZoneMaintStats> I<true>|I<false>
+
+Collect zone maintenance statistics, mostly information about notifications
+(zone updates) and zone transfers.
+
+Default: Enabled.
+
+=item B<ResolverStats> I<true>|I<false>
+
+Collect resolver statistics, i.E<nbsp>e. statistics about outgoing requests
+(e.E<nbsp>g. queries over IPv4, lame servers). Since the global resolver
+counters apparently were removed in BIND 9.5.1 and 9.6.0, this is disabled by
+default. Use the B<ResolverStats> option within a B<View "_default"> block
+instead for the same functionality.
+
+Default: Disabled.
+
+=item B<MemoryStats>
+
+Collect global memory statistics.
+
+Default: Enabled.
+
+=item B<View> I<Name>
+
+Collect statistics about a specific I<"view">. BIND can behave different,
+mostly depending on the source IP-address of the request. These different
+configurations are called "views". If you don't use this feature, you most
+likely are only interested in the C<_default> view.
+
+Within a E<lt>B<View>E<nbsp>I<name>E<gt> block, you can specify which
+information you want to collect about a view. If no B<View> block is
+configured, no detailed view statistics will be collected.
+
+=over 4
+
+=item B<QTypes> I<true>|I<false>
+
+If enabled, the number of I<outgoing> queries by query type (e.E<nbsp>g. C<A>,
+C<MX>) is collected.
+
+Default: Enabled.
+
+=item B<ResolverStats> I<true>|I<false>
+
+Collect resolver statistics, i.E<nbsp>e. statistics about outgoing requests
+(e.E<nbsp>g. queries over IPv4, lame servers).
+
+Default: Enabled.
+
+=item B<CacheRRSets> I<true>|I<false>
+
+If enabled, the number of entries (I<"RR sets">) in the view's cache by query
+type is collected. Negative entries (queries which resulted in an error, for
+example names that do not exist) are reported with a leading exclamation mark,
+e.E<nbsp>g. "!A".
+
+Default: Enabled.
+
+=item B<Zone> I<Name>
+
+When given, collect detailed information about the given zone in the view. The
+information collected if very similar to the global B<ServerStats> information
+(see above).
+
+You can repeat this option to collect detailed information about multiple
+zones.
+
+By default no detailed zone information is collected.
+
+=back
+
+=back
+
+=head2 Plugin C<couchdb>
+
+The couchdb plugin uses B<libcurl> (L<http://curl.haxx.se/>) and B<libyajl>
+(L<http://www.lloydforge.org/projects/yajl/>) to collect values from CouchDB
+documents (stored JSON notation).
+
+The following example will collect several values from the built-in `_stats'
+runtime statistics module (L<http://wiki.apache.org/couchdb/Runtime_Statistics>).
+
+ <Plugin couchdb>
+ <URL "http://localhost:5984/_stats">
+ Instance "httpd"
+ <Key "httpd/requests/count">
+ Type "http_requests"
+ </Key>
+
+ <Key "httpd_request_methods/*/count">
+ Type "http_request_methods"
+ </Key>
+
+ <Key "httpd_status_codes/*/count">
+ Type "http_response_codes"
+ </Key>
+ </URL>
+ </Plugin>
+
+The following example will collect the status values from each database:
+
+ <URL "http://localhost:5984/_all_dbs">
+ Instance "dbs"
+ <Key "*/doc_count">
+ Type "gauge"
+ </Key>
+ <Key "*/doc_del_count">
+ Type "counter"
+ </Key>
+ <Key "*/disk_size">
+ Type "bytes"
+ </Key>
+ </URL>
+
+In the B<Plugin> block, there may be one or more B<URL> blocks, each defining
+a URL to be fetched via HTTP (libcurl) and one or more B<Key> blocks.
+The B<Key> string argument must be in a path format, of which is used to collect
+a value from a JSON map object. If a B<Key> path element is that of a I<*> wildcard,
+the values for all keys will be collectd.
+
+The following options are valid within B<URL> blocks:
+
+=over 4
+
+=item B<Instance> I<Instance>
+
+Sets the plugin instance to I<Instance>.
+
+=item B<User> I<Name>
+
+Username to use if authorization is required to read the page.
+
+=item B<Password> I<Password>
+
+Password to use if authorization is required to read the page.
+
+=item B<VerifyPeer> B<true>|B<false>
+
+Enable or disable peer SSL certificate verification. See
+L<http://curl.haxx.se/docs/sslcerts.html> for details. Enabled by default.
+
+=item B<VerifyHost> B<true>|B<false>
+
+Enable or disable peer host name verification. If enabled, the plugin checks if
+the C<Common Name> or a C<Subject Alternate Name> field of the SSL certificate
+matches the host name provided by the B<URL> option. If this identity check
+fails, the connection is aborted. Obviously, only works when connecting to a
+SSL enabled server. Enabled by default.
+
+=item B<CACert> I<file>
+
+File that holds one or more SSL certificates. If you want to use HTTPS you will
+possibly need this option. What CA certificates come bundled with C<libcurl>
+and are checked by default depends on the distribution you use.
+
+=back
+
+The following options are valid within B<Key> blocks:
+
+=over 4
+
+=item B<Type> I<Type>
+
+Sets the type used to dispatch the values to the daemon. Detailed information
+about types and their configuration can be found in L<types.db(5)>. This
+option is mandatory.
+
+=item B<Instance> I<Instance>
+
+Type-instance to use. Defaults to the current map key or current string array element value.
+
+=back
+
=head2 Plugin C<cpufreq>
This plugin doesn't have any options. It reads
Set the directory to store CSV-files under. Per default CSV-files are generated
beneath the daemon's working directory, i.E<nbsp>e. the B<BaseDir>.
+The special strings B<stdout> and B<stderr> can be used to write to the standard
+output and standard error channels, respectively. This, of course, only makes
+much sense when collectd is running in foreground- or non-daemon-mode.
=item B<StoreRates> B<true|false>
=back
+=head2 Plugin C<curl>
+
+The curl plugin uses the B<libcurl> (L<http://curl.haxx.se/>) to read web pages
+and the match infrastructure (the same code used by the tail plugin) to use
+regular expressions with the received data.
+
+The following example will read the current value of AMD stock from google's
+finance page and dispatch the value to collectd.
+
+ <Plugin curl>
+ <Page "stock_quotes">
+ URL "http://finance.google.com/finance?q=NYSE%3AAMD"
+ User "foo"
+ Password "bar"
+ <Match>
+ Regex "<span +class=\"pr\"[^>]*> *([0-9]*\\.[0-9]+) *</span>"
+ DSType "GaugeAverage"
+ # Note: `stock_value' is not a standard type.
+ Type "stock_value"
+ Instance "AMD"
+ </Match>
+ </Page>
+ </Plugin>
+
+In the B<Plugin> block, there may be one or more B<Page> blocks, each defining
+a web page and one or more "matches" to be performed on the returned data. The
+string argument to the B<Page> block is used as plugin instance.
+
+The following options are valid within B<Page> blocks:
+
+=over 4
+
+=item B<URL> I<URL>
+
+URL of the web site to retrieve. Since a regular expression will be used to
+extract information from this data, non-binary data is a big plus here ;)
+
+=item B<User> I<Name>
+
+Username to use if authorization is required to read the page.
+
+=item B<Password> I<Password>
+
+Password to use if authorization is required to read the page.
+
+=item B<VerifyPeer> B<true>|B<false>
+
+Enable or disable peer SSL certificate verification. See
+L<http://curl.haxx.se/docs/sslcerts.html> for details. Enabled by default.
+
+=item B<VerifyHost> B<true>|B<false>
+
+Enable or disable peer host name verification. If enabled, the plugin checks if
+the C<Common Name> or a C<Subject Alternate Name> field of the SSL certificate
+matches the host name provided by the B<URL> option. If this identity check
+fails, the connection is aborted. Obviously, only works when connecting to a
+SSL enabled server. Enabled by default.
+
+=item B<CACert> I<file>
+
+File that holds one or more SSL certificates. If you want to use HTTPS you will
+possibly need this option. What CA certificates come bundled with C<libcurl>
+and are checked by default depends on the distribution you use.
+
+=item B<E<lt>MatchE<gt>>
+
+One or more B<Match> blocks that define how to match information in the data
+returned by C<libcurl>. The C<curl> plugin uses the same infrastructure that's
+used by the C<tail> plugin, so please see the documentation of the C<tail>
+plugin below on how matches are defined.
+
+=back
+
+=head2 Plugin C<dbi>
+
+This plugin uses the B<dbi> library (L<http://libdbi.sourceforge.net/>) to
+connect to various databases, execute I<SQL> statements and read back the
+results. I<dbi> is an acronym for "database interface" in case you were
+wondering about the name. You can configure how each column is to be
+interpreted and the plugin will generate one or more data sets from each row
+returned according to these rules.
+
+Because the plugin is very generic, the configuration is a little more complex
+than those of other plugins. It usually looks something like this:
+
+ <Plugin dbi>
+ <Query "out_of_stock">
+ Statement "SELECT category, COUNT(*) AS value FROM products WHERE in_stock = 0 GROUP BY category"
+ # Use with MySQL 5.0.0 or later
+ MinVersion 50000
+ <Result>
+ Type "gauge"
+ InstancePrefix "out_of_stock"
+ InstancesFrom "category"
+ ValuesFrom "value"
+ </Result>
+ </Query>
+ <Database "product_information">
+ Driver "mysql"
+ DriverOption "host" "localhost"
+ DriverOption "username" "collectd"
+ DriverOption "password" "aZo6daiw"
+ DriverOption "dbname" "prod_info"
+ SelectDB "prod_info"
+ Query "out_of_stock"
+ </Database>
+ </Plugin>
+
+The configuration above defines one query with one result and one database. The
+query is then linked to the database with the B<Query> option I<within> the
+B<E<lt>DatabaseE<gt>> block. You can have any number of queries and databases
+and you can also use the B<Include> statement to split up the configuration
+file in multiple, smaller files. However, the B<E<lt>QueryE<gt>> block I<must>
+precede the B<E<lt>DatabaseE<gt>> blocks, because the file is interpreted from
+top to bottom!
+
+The following is a complete list of options:
+
+=head3 B<Query> blocks
+
+Query blocks define I<SQL> statements and how the returned data should be
+interpreted. They are identified by the name that is given in the opening line
+of the block. Thus the name needs to be unique. Other than that, the name is
+not used in collectd.
+
+In each B<Query> block, there is one or more B<Result> blocks. B<Result> blocks
+define which column holds which value or instance information. You can use
+multiple B<Result> blocks to create multiple values from one returned row. This
+is especially useful, when queries take a long time and sending almost the same
+query again and again is not desirable.
+
+Example:
+
+ <Query "environment">
+ Statement "select station, temperature, humidity from environment"
+ <Result>
+ Type "temperature"
+ # InstancePrefix "foo"
+ InstancesFrom "station"
+ ValuesFrom "temperature"
+ </Result>
+ <Result>
+ Type "humidity"
+ InstancesFrom "station"
+ ValuesFrom "humidity"
+ </Result>
+ </Query>
+
+The following options are accepted:
+
+=over 4
+
+=item B<Statement> I<SQL>
+
+Sets the statement that should be executed on the server. This is B<not>
+interpreted by collectd, but simply passed to the database server. Therefore,
+the SQL dialect that's used depends on the server collectd is connected to.
+
+The query has to return at least two columns, one for the instance and one
+value. You cannot omit the instance, even if the statement is guaranteed to
+always return exactly one line. In that case, you can usually specify something
+like this:
+
+ Statement "SELECT \"instance\", COUNT(*) AS value FROM table"
+
+(That works with MySQL but may not be valid SQL according to the spec. If you
+use a more strict database server, you may have to select from a dummy table or
+something.)
+
+Please note that some databases, for example B<Oracle>, will fail if you
+include a semicolon at the end of the statement.
+
+=item B<MinVersion> I<Version>
+
+=item B<MaxVersion> I<Value>
+
+Only use this query for the specified database version. You can use these
+options to provide multiple queries with the same name but with a slightly
+different syntax. The plugin will use only those queries, where the specified
+minimum and maximum versions fit the version of the database in use.
+
+The database version is determined by C<dbi_conn_get_engine_version>, see the
+L<libdbi documentation|http://libdbi.sourceforge.net/docs/programmers-guide/reference-conn.html#DBI-CONN-GET-ENGINE-VERSION>
+for details. Basically, each part of the version is assumed to be in the range
+from B<00> to B<99> and all dots are removed. So version "4.1.2" becomes
+"40102", version "5.0.42" becomes "50042".
+
+B<Warning:> The plugin will use B<all> matching queries, so if you specify
+multiple queries with the same name and B<overlapping> ranges, weird stuff will
+happen. Don't to it! A valid example would be something along these lines:
+
+ MinVersion 40000
+ MaxVersion 49999
+ ...
+ MinVersion 50000
+ MaxVersion 50099
+ ...
+ MinVersion 50100
+ # No maximum
+
+In the above example, there are three ranges that don't overlap. The last one
+goes from version "5.1.0" to infinity, meaning "all later versions". Versions
+before "4.0.0" are not specified.
+
+=item B<Type> I<Type>
+
+The B<type> that's used for each line returned. See L<types.db(5)> for more
+details on how types are defined. In short: A type is a predefined layout of
+data and the number of values and type of values has to match the type
+definition.
+
+If you specify "temperature" here, you need exactly one gauge column. If you
+specify "if_octets", you will need two counter columns. See the B<ValuesFrom>
+setting below.
+
+There must be exactly one B<Type> option inside each B<Result> block.
+
+=item B<InstancePrefix> I<prefix>
+
+Prepends I<prefix> to the type instance. If B<InstancesFrom> (see below) is not
+given, the string is simply copied. If B<InstancesFrom> is given, I<prefix> and
+all strings returned in the appropriate columns are concatenated together,
+separated by dashes I<("-")>.
+
+=item B<InstancesFrom> I<column0> [I<column1> ...]
+
+Specifies the columns whose values will be used to create the "type-instance"
+for each row. If you specify more than one column, the value of all columns
+will be joined together with dashes I<("-")> as separation characters.
+
+The plugin itself does not check whether or not all built instances are
+different. It's your responsibility to assure that each is unique. This is
+especially true, if you do not specify B<InstancesFrom>: B<You> have to make
+sure that only one row is returned in this case.
+
+If neither B<InstancePrefix> nor B<InstancesFrom> is given, the type-instance
+will be empty.
+
+=item B<ValuesFrom> I<column0> [I<column1> ...]
+
+Names the columns whose content is used as the actual data for the data sets
+that are dispatched to the daemon. How many such columns you need is determined
+by the B<Type> setting above. If you specify too many or not enough columns,
+the plugin will complain about that and no data will be submitted to the
+daemon.
+
+The actual data type in the columns is not that important. The plugin will
+automatically cast the values to the right type if it know how to do that. So
+it should be able to handle integer an floating point types, as well as strings
+(if they include a number at the beginning).
+
+There must be at least one B<ValuesFrom> option inside each B<Result> block.
+
+=back
+
+=head3 B<Database> blocks
+
+Database blocks define a connection to a database and which queries should be
+sent to that database. Since the used "dbi" library can handle a wide variety
+of databases, the configuration is very generic. If in doubt, refer to libdbi's
+documentationE<nbsp>- we stick as close to the terminology used there.
+
+Each database needs a "name" as string argument in the starting tag of the
+block. This name will be used as "PluginInstance" in the values submitted to
+the daemon. Other than that, that name is not used.
+
+=over 4
+
+=item B<Driver> I<Driver>
+
+Specifies the driver to use to connect to the database. In many cases those
+drivers are named after the database they can connect to, but this is not a
+technical necessity. These drivers are sometimes referred to as "DBD",
+B<D>ataB<B>ase B<D>river, and some distributions ship them in separate
+packages. Drivers for the "dbi" library are developed by the B<libdbi-drivers>
+project at L<http://libdbi-drivers.sourceforge.net/>.
+
+You need to give the driver name as expected by the "dbi" library here. You
+should be able to find that in the documentation for each driver. If you
+mistype the driver name, the plugin will dump a list of all known driver names
+to the log.
+
+=item B<DriverOption> I<Key> I<Value>
+
+Sets driver-specific options. What option a driver supports can be found in the
+documentation for each driver, somewhere at
+L<http://libdbi-drivers.sourceforge.net/>. However, the options "host",
+"username", "password", and "dbname" seem to be deE<nbsp>facto standards.
+
+Unfortunately, drivers are not too keen to report errors when an unknown option
+is passed to them, so invalid settings here may go unnoticed. This is not the
+plugin's fault, it will report errors if it gets them from the libraryE<nbsp>/
+the driver. If a driver complains about an option, the plugin will dump a
+complete list of all options understood by that driver to the log.
+
+=item B<SelectDB> I<Database>
+
+In some cases, the database name you connect with is not the database name you
+want to use for querying data. If this option is set, the plugin will "select"
+(switch to) that database after the connection is established.
+
+=item B<Query> I<QueryName>
+
+Associates the query named I<QueryName> with this database connection. The
+query needs to be defined I<before> this statement, i.E<nbsp>e. all query
+blocks you want to refer to must be placed above the database block you want to
+refer to them from.
+
+=back
+
=head2 Plugin C<df>
=over 4
Ignore packets that originate from this address.
+=item B<SelectNumericQueryTypes> B<true>|B<false>
+
+Enabled by default, collects unknown (and thus presented as numeric only) query types.
+
=back
=head2 Plugin C<email>
C<m> (megabyte), C<g> (gigabyte), C<t> (terabyte), and C<p> (petabyte). Please
note that there are 1000 bytes in a kilobyte, not 1024.
+=item B<Recursive> I<true>|I<false>
+
+Controls whether or not to recurse into subdirectories. Enabled by default.
+
+=back
+
+=head2 Plugin C<gmond>
+
+The I<gmond> plugin received the multicast traffic sent by B<gmond>, the
+statistics collection daemon of Ganglia. Mappings for the standard "metrics"
+are built-in, custom mappings may be added via B<Metric> blocks, see below.
+
+Synopsis:
+
+ <Plugin "gmond">
+ MCReceiveFrom "239.2.11.71" "8649"
+ <Metric "swap_total">
+ Type "swap"
+ TypeInstance "total"
+ DataSource "value"
+ </Metric>
+ <Metric "swap_free">
+ Type "swap"
+ TypeInstance "free"
+ DataSource "value"
+ </Metric>
+ </Plugin>
+
+The following metrics are built-in:
+
+=over 4
+
+=item *
+
+load_one, load_five, load_fifteen
+
+=item *
+
+cpu_user, cpu_system, cpu_idle, cpu_nice, cpu_wio
+
+=item *
+
+mem_free, mem_shared, mem_buffers, mem_cached, mem_total
+
+=item *
+
+bytes_in, bytes_out
+
+=item *
+
+pkts_in, pkts_out
+
+=back
+
+Available configuration options:
+
+=over 4
+
+=item B<MCReceiveFrom> I<MCGroup> [I<Port>]
+
+Sets sets the multicast group and UDP port to which to subscribe.
+
+Default: B<239.2.11.71>E<nbsp>/E<nbsp>B<8649>
+
+=item E<lt>B<Metric> I<Name>E<gt>
+
+These blocks add a new metric conversion to the internal table. I<Name>, the
+string argument to the B<Metric> block, is the metric name as used by Ganglia.
+
+=over 4
+
+=item B<Type> I<Type>
+
+Type to map this metric to. Required.
+
+=item B<TypeInstance> I<Instance>
+
+Type-instance to use. Optional.
+
+=item B<DataSource> I<Name>
+
+Data source to map this metric to. If the configured type has exactly one data
+source, this is optional. Otherwise the option is required.
+
+=back
+
=back
=head2 Plugin C<hddtemp>
=back
+=head2 Plugin C<java>
+
+The I<Java> plugin makes it possible to write extensions for collectd in Java.
+This section only discusses the syntax and semantic of the configuration
+options. For more in-depth information on the I<Java> plugin, please read
+L<collectd-java(5)>.
+
+Synopsis:
+
+ <Plugin "java">
+ JVMArg "-verbose:jni"
+ JVMArg "-Djava.class.path=/opt/collectd/lib/collectd/bindings/java"
+ LoadPlugin "org.collectd.java.Foobar"
+ <Plugin "org.collectd.java.Foobar">
+ # To be parsed by the plugin
+ </Plugin>
+ </Plugin>
+
+Available configuration options:
+
+=over 4
+
+=item B<JVMArg> I<Argument>
+
+Argument that is to be passed to the I<Java Virtual Machine> (JVM). This works
+exactly the way the arguments to the I<java> binary on the command line work.
+Execute C<javaE<nbsp>--help> for details.
+
+Please note that B<all> these options must appear B<before> (i.E<nbsp>e. above)
+any other options! When another option is found, the JVM will be started and
+later options will have to be ignored!
+
+=item B<LoadPlugin> I<JavaClass>
+
+Instantiates a new I<JavaClass> object. The constructor of this object very
+likely then registers one or more callback methods with the server.
+
+See L<collectd-java(5)> for details.
+
+When the first such option is found, the virtual machine (JVM) is created. This
+means that all B<JVMArg> options must appear before (i.E<nbsp>e. above) all
+B<LoadPlugin> options!
+
+=item B<Plugin> I<Name>
+
+The entire block is passed to the Java plugin as an
+I<org.collectd.api.OConfigItem> object.
+
+For this to work, the plugin has to register a configuration callback first,
+see L<collectd-java(5)/"config callback">. This means, that the B<Plugin> block
+must appear after the appropriate B<LoadPlugin> block. Also note, that I<Name>
+depends on the (Java) plugin registering the callback and is completely
+independent from the I<JavaClass> argument passed to B<LoadPlugin>.
+
+=back
+
=head2 Plugin C<libvirt>
This plugin allows CPU, disk and network load to be collected for virtualized
=back
+B<Note>: There is no need to notify the daemon after moving or removing the
+log file (e.E<nbsp>g. when rotating the logs). The plugin reopens the file
+for each line it writes.
+
=head2 Plugin C<mbmon>
The C<mbmon plugin> uses mbmon to retrieve temperature, voltage, etc.
=back
-=head2 Plugin C<memcached>
+=head2 Plugin C<memcachec>
-The C<memcached plugin> connects to a memcached server and queries statistics
-about cache utilization, memory and bandwidth used.
-L<http://www.danga.com/memcached/>
+The C<memcachec plugin> connects to a memcached server, queries one or more
+given I<pages> and parses the returned data according to user specification.
+The I<matches> used are the same as the matches used in the C<curl> and C<tail>
+plugins.
-=over 4
+In order to talk to the memcached server, this plugin uses the I<libmemcached>
+library. Please note that there is another library with a very similar name,
+libmemcache (notice the missing `d'), which is not applicable.
+
+Synopsis of the configuration:
+
+ <Plugin "memcachec">
+ <Page "plugin_instance">
+ Server "localhost"
+ Key "page_key"
+ <Match>
+ Regex "(\\d+) bytes sent"
+ DSType CounterAdd
+ Type "ipt_octets"
+ Instance "type_instance"
+ </Match>
+ </Page>
+ </Plugin>
+
+The configuration options are:
+
+=over 4
+
+=item E<lt>B<Page> I<Name>E<gt>
+
+Each B<Page> block defines one I<page> to be queried from the memcached server.
+The block requires one string argument which is used as I<plugin instance>.
+
+=item B<Server> I<Address>
+
+Sets the server address to connect to when querying the page. Must be inside a
+B<Page> block.
+
+=item B<Key> I<Key>
+
+When connected to the memcached server, asks for the page I<Key>.
+
+=item E<lt>B<Match>E<gt>
+
+Match blocks define which strings to look for and how matches substrings are
+interpreted. For a description of match blocks, please see L<"Plugin tail">.
+
+=back
+
+=head2 Plugin C<memcached>
+
+The C<memcached plugin> connects to a memcached server and queries statistics
+about cache utilization, memory and bandwidth used.
+L<http://www.danga.com/memcached/>
+
+=over 4
=item B<Host> I<Hostname>
=head2 Plugin C<mysql>
-The C<mysql plugin> requires B<mysqlclient> to be installed. It connects to the
-database when started and keeps the connection up as long as possible. When the
-connection is interrupted for whatever reason it will try to re-connect. The
-plugin will complaint loudly in case anything goes wrong.
+The C<mysql plugin> requires B<mysqlclient> to be installed. It connects to
+one or more databases when started and keeps the connection up as long as
+possible. When the connection is interrupted for whatever reason it will try
+to re-connect. The plugin will complaint loudly in case anything goes wrong.
+
+This plugin issues the MySQL C<SHOW STATUS> / C<SHOW GLOBAL STATUS> command
+and collects information about MySQL network traffic, executed statements,
+requests, the query cache and threads by evaluating the
+C<Bytes_{received,sent}>, C<Com_*>, C<Handler_*>, C<Qcache_*> and C<Threads_*>
+return values. Please refer to the B<MySQL reference manual>, I<5.1.6. Server
+Status Variables> for an explanation of these values.
+
+Optionally, master and slave statistics may be collected in a MySQL
+replication setup. In that case, information about the synchronization state
+of the nodes are collected by evaluating the C<Position> return value of the
+C<SHOW MASTER STATUS> command and the C<Seconds_Behind_Master>,
+C<Read_Master_Log_Pos> and C<Exec_Master_Log_Pos> return values of the
+C<SHOW SLAVE STATUS> command. See the B<MySQL reference manual>,
+I<12.5.5.21 SHOW MASTER STATUS Syntax> and
+I<12.5.5.31 SHOW SLAVE STATUS Syntax> for details.
+
+Synopsis:
+
+ <Plugin mysql>
+ <Database foo>
+ Host "hostname"
+ User "username"
+ Password "password"
+ Port "3306"
+ MasterStats true
+ </Database>
-This plugin issues the MySQL C<SHOW STATUS> command and collects information
-about MySQL network traffic, executed statements, requests, the query cache
-and threads by evaluating the C<Bytes_{received,sent}>, C<Com_*>,
-C<Handler_*>, C<Qcache_*> and C<Threads_*> return values. Please refer to the
-B<MySQL reference manual>, I<5.1.6. Server Status Variables> for an
-explanation of these values.
+ <Database bar>
+ Host "localhost"
+ Socket "/var/run/mysql/mysqld.sock"
+ SlaveStats true
+ SlaveNotifications true
+ </Database>
+ </Plugin>
-Use the following options to configure the plugin:
+A B<Database> block defines one connection to a MySQL database. It accepts a
+single argument which specifies the name of the database. None of the other
+options are required. MySQL will use default values as documented in the
+section "mysql_real_connect()" in the B<MySQL reference manual>.
=over 4
Select this database. Defaults to I<no database> which is a perfectly reasonable
option for what this plugin does.
+=item B<Port> I<Port>
+
+TCP-port to connect to. The port must be specified in its numeric form, but it
+must be passed as a string nonetheless. For example:
+
+ Port "3306"
+
+If B<Host> is set to B<localhost> (the default), this setting has no effect.
+See the documentation for the C<mysql_real_connect> function for details.
+
+=item B<Socket> I<Socket>
+
+Specifies the path to the UNIX domain socket of the MySQL server. This option
+only has any effect, if B<Host> is set to B<localhost> (the default).
+Otherwise, use the B<Port> option above. See the documentation for the
+C<mysql_real_connect> function for details.
+
+=item B<MasterStats> I<true|false>
+
+=item B<SlaveStats> I<true|false>
+
+Enable the collection of master / slave statistics in a replication setup.
+
+=item B<SlaveNotifications> I<true|false>
+
+If enabled, the plugin sends a notification if the replication slave I/O and /
+or SQL threads are not running.
+
=back
=head2 Plugin C<netlink>
=head2 Plugin C<network>
+The Network plugin sends data to a remote instance of collectd, receives data
+from a remote instance, or both at the same time. Data which has been received
+from the network is usually not transmitted again, but this can be actived, see
+the B<Forward> option below.
+
+The default IPv6 multicast group is C<ff18::efc0:4a42>. The default IPv4
+multicast group is C<239.192.74.66>. The default I<UDP> port is B<25826>.
+
+Both, B<Server> and B<Listen> can be used as single option or as block. When
+used as block, given options are valid for this socket only. For example:
+
+ <Plugin "network">
+ Server "collectd.internal.tld"
+ <Server "collectd.external.tld">
+ SecurityLevel "sign"
+ Username "myhostname"
+ Password "ohl0eQue"
+ </Server>
+ </Plugin>
+
+=over 4
+
+=item B<E<lt>Server> I<Host> [I<Port>]B<E<gt>>
+
+The B<Server> statement/block sets the server to send datagrams to. The
+statement may occur multiple times to send each datagram to multiple
+destinations.
+
+The argument I<Host> may be a hostname, an IPv4 address or an IPv6 address. The
+optional second argument specifies a port number or a service name. If not
+given, the default, B<25826>, is used.
+
+The following options are recognized within B<Server> blocks:
+
=over 4
-=item B<Listen> I<Host> [I<Port>]
+=item B<SecurityLevel> B<Encrypt>|B<Sign>|B<None>
+
+Set the security you require for network communication. When the security level
+has been set to B<Encrypt>, data sent over the network will be encrypted using
+I<AES-256>. The integrity of encrypted packets is ensured using I<SHA-1>. When
+set to B<Sign>, transmitted data is signed using the I<HMAC-SHA-256> message
+authentication code. When set to B<None>, data is sent without any security.
+
+This feature is only available if the I<network> plugin was linked with
+I<libgcrypt>.
+
+=item B<Username> I<Username>
+
+Sets the username to transmit. This is used by the server to lookup the
+password. See B<AuthFile> below. All security levels except B<None> require
+this setting.
+
+This feature is only available if the I<network> plugin was linked with
+I<libgcrypt>.
+
+=item B<Password> I<Password>
-=item B<Server> I<Host> [I<Port>]
+Sets a password (shared secret) for this socket. All security levels except
+B<None> require this setting.
-The B<Server> statement sets the server to send datagrams B<to>. The statement
-may occur multiple times to send each datagram to multiple destinations.
+This feature is only available if the I<network> plugin was linked with
+I<libgcrypt>.
+
+=back
+
+=item B<E<lt>Listen> I<Host> [I<Port>]B<E<gt>>
The B<Listen> statement sets the interfaces to bind to. When multiple
statements are found the daemon will bind to multiple interfaces.
The argument I<Host> may be a hostname, an IPv4 address or an IPv6 address. If
the argument is a multicast address the daemon will join that multicast group.
+The optional second argument specifies a port number or a service name. If not
+given, the default, B<25826>, is used.
-If no B<Listen> statement is found the server tries join both, the default IPv6
-multicast group and the default IPv4 multicast group. If no B<Server> statement
-is found the client will try to send data to the IPv6 multicast group first. If
-that fails the client will try the IPv4 multicast group.
+The following options are recognized within C<E<lt>ListenE<gt>> blocks:
-The default IPv6 multicast group is C<ff18::efc0:4a42>. The default IPv4
-multicast group is C<239.192.74.66>.
+=over 4
+
+=item B<SecurityLevel> B<Encrypt>|B<Sign>|B<None>
+
+Set the security you require for network communication. When the security level
+has been set to B<Encrypt>, only encrypted data will be accepted. The integrity
+of encrypted packets is ensured using I<SHA-1>. When set to B<Sign>, only
+signed and encrypted data is accepted. When set to B<None>, all data will be
+accepted. If an B<AuthFile> option was given (see below), encrypted data is
+decrypted if possible.
+
+This feature is only available if the I<network> plugin was linked with
+I<libgcrypt>.
-The optional I<Port> argument sets the port to use. It can either be given
-using a numeric port number or a service name. If the argument is omitted the
-default port B<25826> is assumed.
+=item B<AuthFile> I<Filename>
+
+Sets a file in which usernames are mapped to passwords. These passwords are
+used to verify signatures and to decrypt encrypted network packets. If
+B<SecurityLevel> is set to B<None>, this is optional. If given, signed data is
+verified and encrypted packets are decrypted. Otherwise, signed data is
+accepted without checking the signature and encrypted data cannot be decrypted.
+For the other security levels this option is mandatory.
+
+The file format is very simple: Each line consists of a username followed by a
+colon and any number of spaces followed by the password. To demonstrate, an
+example file could look like this:
+
+ user0: foo
+ user1: bar
+
+Each time a packet is received, the modification time of the file is checked
+using L<stat(2)>. If the file has been changed, the contents is re-read. While
+the file is being read, it is locked using L<fcntl(2)>.
+
+=back
=item B<TimeToLive> I<1-255>
=back
+=head2 Plugin C<olsrd>
+
+The I<olsrd> plugin connects to the TCP port opened by the I<txtinfo> plugin of
+the Optimized Link State Routing daemon and reads information about the current
+state of the meshed network.
+
+The following configuration options are understood:
+
+=over 4
+
+=item B<Host> I<Host>
+
+Connect to I<Host>. Defaults to B<"localhost">.
+
+=item B<Port> I<Port>
+
+Specifies the port to connect to. This must be a string, even if you give the
+port as a number rather than a service name. Defaults to B<"2006">.
+
+=item B<CollectLinks> B<No>|B<Summary>|B<Detail>
+
+Specifies what information to collect about links, i.E<nbsp>e. direct
+connections of the daemon queried. If set to B<No>, no information is
+collected. If set to B<Summary>, the number of links and the average of all
+I<link quality> (LQ) and I<neighbor link quality> (NLQ) values is calculated.
+If set to B<Detail> LQ and NLQ are collected per link.
+
+Defaults to B<Detail>.
+
+=item B<CollectRoutes> B<No>|B<Summary>|B<Detail>
+
+Specifies what information to collect about routes of the daemon queried. If
+set to B<No>, no information is collected. If set to B<Summary>, the number of
+routes and the average I<metric> and I<ETX> is calculated. If set to B<Detail>
+metric and ETX are collected per route.
+
+Defaults to B<Summary>.
+
+=item B<CollectTopology> B<No>|B<Summary>|B<Detail>
+
+Specifies what information to collect about the global topology. If set to
+B<No>, no information is collected. If set to B<Summary>, the number of links
+in the entire topology and the average I<link quality> (LQ) is calculated.
+If set to B<Detail> LQ and NLQ are collected for each link in the entire topology.
+
+Defaults to B<Summary>.
+
+=back
+
=head2 Plugin C<onewire>
B<EXPERIMENTAL!> See notes below.
B<Sensor> is inverted: All selected interfaces are ignored and all other
interfaces are collected.
+=item B<Interval> I<Seconds>
+
+Sets the interval in which all sensors should be read. If not specified, the
+global B<Interval> setting is used.
+
=back
B<EXPERIMENTAL!> The C<onewire> plugin is experimental, because it doesn't yet
or two, reading all values will take more than ten seconds (the default
interval). We will probably add some separate thread for reading the sensors
and some cache or something like that, but it's not done yet. We will try to
-maintain backwards compatibility in the future, but we can't probmise. So in
-short: If it works for you: Great! But kaap in mind that the config I<might>
+maintain backwards compatibility in the future, but we can't promise. So in
+short: If it works for you: Great! But keep in mind that the config I<might>
change, though this is unlikely. Oh, and if you want to help improving this
plugin, just send a short notice to the mailing list. ThanksE<nbsp>:)
+=head2 Plugin C<openvpn>
+
+The OpenVPN plugin reads a status file maintained by OpenVPN and gathers
+traffic statistics about connected clients.
+
+To set up OpenVPN to write to the status file periodically, use the
+B<--status> option of OpenVPN. Since OpenVPN can write two different formats,
+you need to set the required format, too. This is done by setting
+B<--status-version> to B<2>.
+
+So, in a nutshell you need:
+
+ openvpn $OTHER_OPTIONS \
+ --status "/var/run/openvpn-status" 10 \
+ --status-version 2
+
+Available options:
+
+=over 4
+
+=item B<StatusFile> I<File>
+
+Specifies the location of the status file.
+
+=back
+
+=head2 Plugin C<oracle>
+
+The "oracle" plugin uses the Oracle® Call Interface I<(OCI)> to connect to an
+Oracle® Database and lets you execute SQL statements there. It is very similar
+to the "dbi" plugin, because it was written around the same time. See the "dbi"
+plugin's documentation above for details.
+
+ <Plugin oracle>
+ <Query "out_of_stock">
+ Statement "SELECT category, COUNT(*) AS value FROM products WHERE in_stock = 0 GROUP BY category"
+ <Result>
+ Type "gauge"
+ # InstancePrefix "foo"
+ InstancesFrom "category"
+ ValuesFrom "value"
+ </Result>
+ </Query>
+ <Database "product_information">
+ ConnectID "db01"
+ Username "oracle"
+ Password "secret"
+ Query "out_of_stock"
+ </Database>
+ </Plugin>
+
+=head3 B<Query> blocks
+
+The Query blocks are handled identically to the Query blocks of the "dbi"
+plugin. Please see its documentation above for details on how to specify
+queries.
+
+=head3 B<Database> blocks
+
+Database blocks define a connection to a database and which queries should be
+sent to that database. Each database needs a "name" as string argument in the
+starting tag of the block. This name will be used as "PluginInstance" in the
+values submitted to the daemon. Other than that, that name is not used.
+
+=over 4
+
+=item B<ConnectID> I<ID>
+
+Defines the "database alias" or "service name" to connect to. Usually, these
+names are defined in the file named C<$ORACLE_HOME/network/admin/tnsnames.ora>.
+
+=item B<Username> I<Username>
+
+Username used for authentication.
+
+=item B<Password> I<Password>
+
+Password used for authentication.
+
+=item B<Query> I<QueryName>
+
+Associates the query named I<QueryName> with this database connection. The
+query needs to be defined I<before> this statement, i.E<nbsp>e. all query
+blocks you want to refer to must be placed above the database block you want to
+refer to them from.
+
+=back
+
=head2 Plugin C<perl>
This plugin embeds a Perl-interpreter into collectd and provides an interface
=head2 Plugin C<ping>
+The I<Ping> plugin starts a new thread which sends ICMP "ping" packets to the
+configured hosts periodically and measures the network latency. Whenever the
+C<read> function of the plugin is called, it submits the average latency, the
+standard deviation and the drop rate for each host.
+
+Available configuration options:
+
=over 4
=item B<Host> I<IP-address>
Host to ping periodically. This option may be repeated several times to ping
multiple hosts.
+=item B<Interval> I<Seconds>
+
+Sets the interval in which to send ICMP echo packets to the configured hosts.
+This is B<not> the interval in which statistics are queries from the plugin but
+the interval in which the hosts are "pinged". Therefore, the setting here
+should be smaller than or equal to the global B<Interval> setting. Fractional
+times, such as "1.24" are allowed.
+
+Default: B<1.0>
+
+=item B<Timeout> I<Seconds>
+
+Time to wait for a response from the host to which an ICMP packet had been
+sent. If a reply was not received after I<Seconds> seconds, the host is assumed
+to be down or the packet to be dropped. This setting must be smaller than the
+B<Interval> setting above for the plugin to work correctly. Fractional
+arguments are accepted.
+
+Default: B<0.9>
+
=item B<TTL> I<0-255>
Sets the Time-To-Live of generated ICMP packets.
<Plugin postgresql>
<Query magic>
- Query "SELECT magic, spells FROM wizard WHERE host = $1;"
+ Statement "SELECT magic FROM wizard WHERE host = $1;"
Param hostname
- Column gauge magic
- Column counter spells
+ <Result>
+ Type gauge
+ InstancePrefix "magic"
+ ValuesFrom magic
+ </Result>
+ </Query>
+
+ <Query rt36_tickets>
+ Statement "SELECT COUNT(type) AS count, type \
+ FROM (SELECT CASE \
+ WHEN resolved = 'epoch' THEN 'open' \
+ ELSE 'resolved' END AS type \
+ FROM tickets) type \
+ GROUP BY type;"
+ <Result>
+ Type counter
+ InstancePrefix "rt36_tickets"
+ InstancesFrom "type"
+ ValuesFrom "count"
+ </Result>
</Query>
<Database foo>
KRBSrvName "kerberos_service_name"
Query magic
</Database>
+
<Database bar>
Service "service_name"
+ Query backend # predefined
+ Query rt36_tickets
</Database>
</Plugin>
The B<Query> block defines one database query which may later be used by a
database definition. It accepts a single mandatory argument which specifies
-the name of the query. The names of all queries have to be unique. The
-following configuration options are available to define the query:
+the name of the query. The names of all queries have to be unique (see the
+B<MinPGVersion> and B<MaxPGVersion> options below for an exception to this
+rule). The following configuration options are available to define the query:
+
+In each B<Query> block, there is one or more B<Result> blocks. B<Result>
+blocks define how to handle the values returned from the query. They define
+which column holds which value and how to dispatch that value to the daemon.
+Multiple B<Result> blocks may be used to extract multiple values from a single
+query.
=over 4
-=item B<Query> I<sql query>
+=item B<Statement> I<sql query statement>
-Specify the I<sql query> which the plugin should execute. The string may
-contain the tokens B<$1>, B<$2>, etc. which are used to reference the first,
-second, etc. parameter. The value of the parameters is specified by the
+Specify the I<sql query statement> which the plugin should execute. The string
+may contain the tokens B<$1>, B<$2>, etc. which are used to reference the
+first, second, etc. parameter. The value of the parameters is specified by the
B<Param> configuration option - see below for details. To include a literal
B<$> character followed by a number, surround it with single quotes (B<'>).
allowed. Note, however, that only a single command may be used. Semicolons are
allowed as long as a single non-empty command has been specified only.
-=item B<Param> I<hostname>|I<database>|I<username>
+The returned lines will be handled separately one after another.
+
+=item B<Query> I<sql query statement>
+
+This is a deprecated synonym for B<Statement>. It will be removed in version 5
+of collectd.
+
+=item B<Param> I<hostname>|I<database>|I<username>|I<interval>
Specify the parameters which should be passed to the SQL query. The parameters
are referred to in the SQL query as B<$1>, B<$2>, etc. in the same order as
The username used to connect to the database.
+=item I<interval>
+
+The interval collectd is using (as specified by the B<Interval> option).
+
=back
Please note that parameters are only supported by PostgreSQL's protocol
version 3 and above which was introduced in version 7.4 of PostgreSQL.
+=item B<Type> I<type>
+
+The I<type> name to be used when dispatching the values. The type describes
+how to handle the data and where to store it. See L<types.db(5)> for more
+details on types and their configuration. The number and type of values (as
+selected by the B<ValuesFrom> option) has to match the type of the given name.
+
+This option is required inside a B<Result> block.
+
+=item B<InstancePrefix> I<prefix>
+
+=item B<InstancesFrom> I<column0> [I<column1> ...]
+
+Specify how to create the "TypeInstance" for each data set (i.E<nbsp>e. line).
+B<InstancePrefix> defines a static prefix that will be prepended to all type
+instances. B<InstancesFrom> defines the column names whose values will be used
+to create the type instance. Multiple values will be joined together using the
+hyphen (C<->) as separation character.
+
+The plugin itself does not check whether or not all built instances are
+different. It is your responsibility to assure that each is unique.
+
+Both options are optional. If none is specified, the type instance will be
+empty.
+
+=item B<ValuesFrom> I<column0> [I<column1> ...]
+
+Names the columns whose content is used as the actual data for the data sets
+that are dispatched to the daemon. How many such columns you need is
+determined by the B<Type> setting as explained above. If you specify too many
+or not enough columns, the plugin will complain about that and no data will be
+submitted to the daemon.
+
+The actual data type, as seen by PostgreSQL, is not that important as long as
+it represents numbers. The plugin will automatically cast the values to the
+right type if it know how to do that. For that, it uses the L<strtoll(3)> and
+L<strtod(3)> functions, so anything supported by those functions is supported
+by the plugin as well.
+
+This option is required inside a B<Result> block and may be specified multiple
+times. If multiple B<ValuesFrom> options are specified, the columns are read
+in the given order.
+
=item B<Column> I<type> [I<type instance>]
-Specify the I<type> and optional I<type instance> used to dispatch the value
-of each result column. Detailed information about types and their
-configuration can be found in L<types.db(5)>. The number and order of the
-B<Column> options has to match the columns of the query result.
+This is a deprecated alternative to a B<Result> block. It will be removed in
+version 5 of collectd. It is equivalent to the following B<Result> block:
+
+ <Result>
+ Type I<type>
+ InstancePrefix I<type instance>
+ ValuesFrom I<name of the x. column>
+ </Result>
+
+The order of the B<Column> options defines which columns of the query result
+should be used. The first option specifies the data found in the first column,
+the second option that of the second column, and so on.
=item B<MinPGVersion> I<version>
(RSS), user- and system-time used, number of processes and number of threads,
and minor and major pagefaults.
+=item B<ProcessMatch> I<name> I<regex>
+
+Similar to the B<Process> option this allows to select more detailed
+statistics of processes matching the specified I<regex> (see L<regex(7)> for
+details). The statistics of all matching processes are summed up and
+dispatched to the daemon using the specified I<name> as an identifier. This
+allows to "group" several processes together. I<name> must not contain
+slashes.
+
+=back
+
+=head2 Plugin C<protocols>
+
+Collects a lot of information about various network protocols, such as I<IP>,
+I<TCP>, I<UDP>, etc.
+
+Available configuration options:
+
+=over 4
+
+=item B<Value> I<Selector>
+
+Selects whether or not to select a specific value. The string being matched is
+of the form "I<Protocol>:I<ValueName>", where I<Protocol> will be used as the
+plugin instance and I<ValueName> will be used as type instance. An example of
+the string being used would be C<Tcp:RetransSegs>.
+
+You can use regular expressions to match a large number of values with just one
+configuration option. To select all "extended" I<TCP> values, you could use the
+following statement:
+
+ Value "/^TcpExt:/"
+
+Whether only matched values are selected or all matched values are ignored
+depends on the B<IgnoreSelected>. By default, only matched values are selected.
+If no value is configured at all, all values will be selected.
+
+=item B<IgnoreSelected> B<true>|B<false>
+
+If set to B<true>, inverts the selection made by B<Value>, i.E<nbsp>e. all
+matching values will be ignored.
+
+=back
+
+=head2 Plugin C<rrdcached>
+
+The C<rrdcached> plugin uses the RRDTool accelerator daemon, L<rrdcached(1)>,
+to store values to RRD files in an efficient manner. The combination of the
+C<rrdcached> B<plugin> and the C<rrdcached> B<daemon> is very similar to the
+way the C<rrdtool> plugin works (see below). The added abstraction layer
+provides a number of benefits, though: Because the cache is not within
+C<collectd> anymore, it does not need to be flushed when C<collectd> is to be
+restarted. This results in much shorter (if any) gaps in graphs, especially
+under heavy load. Also, the C<rrdtool> command line utility is aware of the
+daemon so that it can flush values to disk automatically when needed. This
+allows to integrate automated flushing of values into graphing solutions much
+more easily.
+
+There are disadvantages, though: The daemon may reside on a different host, so
+it may not be possible for C<collectd> to create the appropriate RRD files
+anymore. And even if C<rrdcached> runs on the same host, it may run in a
+different base directory, so relative paths may do weird stuff if you're not
+careful.
+
+So the B<recommended configuration> is to let C<collectd> and C<rrdcached> run
+on the same host, communicating via a UNIX domain socket. The B<DataDir>
+setting should be set to an absolute path, so that a changed base directory
+does not result in RRD files being createdE<nbsp>/ expected in the wrong place.
+
+=over 4
+
+=item B<DaemonAddress> I<Address>
+
+Address of the daemon as understood by the C<rrdc_connect> function of the RRD
+library. See L<rrdcached(1)> for details. Example:
+
+ <Plugin "rrdcached">
+ DaemonAddress "unix:/var/run/rrdcached.sock"
+ </Plugin>
+
+=item B<DataDir> I<Directory>
+
+Set the base directory in which the RRD files reside. If this is a relative
+path, it is relative to the working base directory of the C<rrdcached> daemon!
+Use of an absolute path is recommended.
+
+=item B<CreateFiles> B<true>|B<false>
+
+Enables or disables the creation of RRD files. If the daemon is not running
+locally, or B<DataDir> is set to a relative path, this will not work as
+expected. Default is B<true>.
+
=back
=head2 Plugin C<rrdtool>
The trade off is that the graphs kind of "drag behind" and that more memory is
used.
-=item B<WritesPerSecond> B<Updates>
+=item B<WritesPerSecond> I<Updates>
When collecting many statistics with collectd and the C<rrdtool> plugin, you
will run serious performance problems. The B<CacheFlush> setting and the
=back
+=head2 Plugin C<table>
+
+The C<table plugin> provides generic means to parse tabular data and dispatch
+user specified values. Values are selected based on column numbers. For
+example, this plugin may be used to get values from the Linux L<proc(5)>
+filesystem or CSV (comma separated values) files.
+
+ <Plugin table>
+ <Table "/proc/slabinfo">
+ Instance "slabinfo"
+ Separator " "
+ <Result>
+ Type gauge
+ InstancePrefix "active_objs"
+ InstancesFrom 0
+ ValuesFrom 1
+ </Result>
+ <Result>
+ Type gauge
+ InstancePrefix "objperslab"
+ InstancesFrom 0
+ ValuesFrom 4
+ </Result>
+ </Table>
+ </Plugin>
+
+The configuration consists of one or more B<Table> blocks, each of which
+configures one file to parse. Within each B<Table> block, there are one or
+more B<Result> blocks, which configure which data to select and how to
+interpret it.
+
+The following options are available inside a B<Table> block:
+
+=over 4
+
+=item B<Instance> I<instance>
+
+If specified, I<instance> is used as the plugin instance. So, in the above
+example, the plugin name C<table-slabinfo> would be used. If omitted, the
+filename of the table is used instead, with all special characters replaced
+with an underscore (C<_>).
+
+=item B<Separator> I<string>
+
+Any character of I<string> is interpreted as a delimiter between the different
+columns of the table. A sequence of two or more contiguous delimiters in the
+table is considered to be a single delimiter, i.E<nbsp>e. there cannot be any
+empty columns. The plugin uses the L<strtok_r(3)> function to parse the lines
+of a table - see its documentation for more details. This option is mandatory.
+
+A horizontal tab, newline and carriage return may be specified by C<\\t>,
+C<\\n> and C<\\r> respectively. Please note that the double backslashes are
+required because of collectd's config parsing.
+
+=back
+
+The following options are available inside a B<Result> block:
+
+=over 4
+
+=item B<Type> I<type>
+
+Sets the type used to dispatch the values to the daemon. Detailed information
+about types and their configuration can be found in L<types.db(5)>. This
+option is mandatory.
+
+=item B<InstancePrefix> I<prefix>
+
+If specified, prepend I<prefix> to the type instance. If omitted, only the
+B<InstancesFrom> option is considered for the type instance.
+
+=item B<InstancesFrom> I<column0> [I<column1> ...]
+
+If specified, the content of the given columns (identified by the column
+number starting at zero) will be used to create the type instance for each
+row. Multiple values (and the instance prefix) will be joined together with
+dashes (I<->) as separation character. If omitted, only the B<InstancePrefix>
+option is considered for the type instance.
+
+The plugin itself does not check whether or not all built instances are
+different. It’s your responsibility to assure that each is unique. This is
+especially true, if you do not specify B<InstancesFrom>: B<You> have to make
+sure that the table only contains one row.
+
+If neither B<InstancePrefix> nor B<InstancesFrom> is given, the type instance
+will be empty.
+
+=item B<ValuesFrom> I<column0> [I<column1> ...]
+
+Specifies the columns (identified by the column numbers starting at zero)
+whose content is used as the actual data for the data sets that are dispatched
+to the daemon. How many such columns you need is determined by the B<Type>
+setting above. If you specify too many or not enough columns, the plugin will
+complain about that and no data will be submitted to the daemon. The plugin
+uses L<strtoll(3)> and L<strtod(3)> to parse counter and gauge values
+respectively, so anything supported by those functions is supported by the
+plugin as well. This option is mandatory.
+
+=back
+
=head2 Plugin C<tail>
-The C<tail plugin> plugins follows logfiles, just like L<tail(1)> does, parses
+The C<tail plugin> follows logfiles, just like L<tail(1)> does, parses
each line and dispatches found values. What is matched can be configured by the
user using (extended) regular expressions, as described in L<regex(7)>.
=back
+=head2 Plugin C<ted>
+
+The I<TED> plugin connects to a device of "The Energy Detective", a device to
+measure power consumption. These devices are usually connected to a serial
+(RS232) or USB port. The plugin opens a configured device and tries to read the
+current energy readings. For more information on TED, visit
+L<http://www.theenergydetective.com/>.
+
+Available configuration options:
+
+=over 4
+
+=item B<Device> I<Path>
+
+Path to the device on which TED is connected. collectd will need read and write
+permissions on that file.
+
+Default: B</dev/ttyUSB0>
+
+=item B<Retries> I<Num>
+
+Apparently reading from TED is not that reliable. You can therefore configure a
+number of retries here. You only configure the I<retries> here, to if you
+specify zero, one reading will be performed (but no retries if that fails); if
+you specify three, a maximum of four readings are performed. Negative values
+are illegal.
+
+Default: B<0>
+
+=back
+
=head2 Plugin C<tcpconns>
The C<tcpconns plugin> counts the number of currently established TCP
The B<VServer> homepage can be found at L<http://linux-vserver.org/>.
+B<Note>: The traffic collected by this plugin accounts for the amount of
+traffic passing a socket which might be a lot less than the actual on-wire
+traffic (e.E<nbsp>g. due to headers and retransmission). If you want to
+collect on-wire traffic you could, for example, use the logging facilities of
+iptables to feed data for the guest IPs into the iptables plugin.
+
=head1 THRESHOLD CONFIGURATION
Starting with version C<4.3.0> collectd has support for B<monitoring>. By that
=back
+=head1 FILTER CONFIGURATION
+
+Starting with collectd 4.6 there is a powerful filtering infrastructure
+implemented in the daemon. The concept has mostly been copied from
+I<ip_tables>, the packet filter infrastructure for Linux. We'll use a similar
+terminology, so that users that are familiar with iptables feel right at home.
+
+=head2 Terminology
+
+The following are the terms used in the remainder of the filter configuration
+documentation. For an ASCII-art schema of the mechanism, see
+L<"General structure"> below.
+
+=over 4
+
+=item B<Match>
+
+A I<match> is a criteria to select specific values. Examples are, of course, the
+name of the value or it's current value.
+
+Matches are implemented in plugins which you have to load prior to using the
+match. The name of such plugins starts with the "match_" prefix.
+
+=item B<Target>
+
+A I<target> is some action that is to be performed with data. Such actions
+could, for example, be to change part of the value's identifier or to ignore
+the value completely.
+
+Some of these targets are built into the daemon, see L<"Built-in targets">
+below. Other targets are implemented in plugins which you have to load prior to
+using the target. The name of such plugins starts with the "target_" prefix.
+
+=item B<Rule>
+
+The combination of any number of matches and at least one target is called a
+I<rule>. The target actions will be performed for all values for which B<all>
+matches apply. If the rule does not have any matches associated with it, the
+target action will be performed for all values.
+
+=item B<Chain>
+
+A I<chain> is a list of rules and possibly default targets. The rules are tried
+in order and if one matches, the associated target will be called. If a value
+is handled by a rule, it depends on the target whether or not any subsequent
+rules are considered or if traversal of the chain is aborted, see
+L<"Flow control"> below. After all rules have been checked, the default targets
+will be executed.
+
+=back
+
+=head2 General structure
+
+The following shows the resulting structure:
+
+ +---------+
+ ! Chain !
+ +---------+
+ !
+ V
+ +---------+ +---------+ +---------+ +---------+
+ ! Rule !->! Match !->! Match !->! Target !
+ +---------+ +---------+ +---------+ +---------+
+ !
+ V
+ +---------+ +---------+ +---------+
+ ! Rule !->! Target !->! Target !
+ +---------+ +---------+ +---------+
+ !
+ V
+ :
+ :
+ !
+ V
+ +---------+ +---------+ +---------+
+ ! Rule !->! Match !->! Target !
+ +---------+ +---------+ +---------+
+ !
+ V
+ +---------+
+ ! Default !
+ ! Target !
+ +---------+
+
+=head2 Flow control
+
+There are four ways to control which way a value takes through the filter
+mechanism:
+
+=over 4
+
+=item B<jump>
+
+The built-in B<jump> target can be used to "call" another chain, i.E<nbsp>e.
+process the value with another chain. When the called chain finishes, usually
+the next target or rule after the jump is executed.
+
+=item B<stop>
+
+The stop condition, signaled for example by the built-in target B<stop>, causes
+all processing of the value to be stopped immediately.
+
+=item B<return>
+
+Causes processing in the current chain to be aborted, but processing of the
+value generally will continue. This means that if the chain was called via
+B<Jump>, the next target or rule after the jump will be executed. If the chain
+was not called by another chain, control will be returned to the daemon and it
+may pass the value to another chain.
+
+=item B<continue>
+
+Most targets will signal the B<continue> condition, meaning that processing
+should continue normally. There is no special built-in target for this
+condition.
+
+=back
+
+=head2 Synopsis
+
+The configuration reflects this structure directly:
+
+ PostCacheChain "PostCache"
+ <Chain "PostCache">
+ <Rule "ignore_mysql_show">
+ <Match "regex">
+ Plugin "^mysql$"
+ Type "^mysql_command$"
+ TypeInstance "^show_"
+ </Match>
+ <Target "stop">
+ </Target>
+ </Rule>
+ <Target "write">
+ Plugin "rrdtool"
+ </Target>
+ </Chain>
+
+The above configuration example will ignore all values where the plugin field
+is "mysql", the type is "mysql_command" and the type instance begins with
+"show_". All other values will be sent to the C<rrdtool> write plugin via the
+default target of the chain. Since this chain is run after the value has been
+added to the cache, the MySQL C<show_*> command statistics will be available
+via the C<unixsock> plugin.
+
+=head2 List of configuration options
+
+=over 4
+
+=item B<PreCacheChain> I<ChainName>
+
+=item B<PostCacheChain> I<ChainName>
+
+Configure the name of the "pre-cache chain" and the "post-cache chain". The
+argument is the name of a I<chain> that should be executed before and/or after
+the values have been added to the cache.
+
+To understand the implications, it's important you know what is going on inside
+I<collectd>. The following diagram shows how values are passed from the
+read-plugins to the write-plugins:
+
+ +---------------+
+ ! Read-Plugin !
+ +-------+-------+
+ !
+ + - - - - V - - - - +
+ : +---------------+ :
+ : ! Pre-Cache ! :
+ : ! Chain ! :
+ : +-------+-------+ :
+ : ! :
+ : V :
+ : +-------+-------+ : +---------------+
+ : ! Cache !--->! Value Cache !
+ : ! insert ! : +---+---+-------+
+ : +-------+-------+ : ! !
+ : ! ,------------' !
+ : V V : V
+ : +-------+---+---+ : +-------+-------+
+ : ! Post-Cache +--->! Write-Plugins !
+ : ! Chain ! : +---------------+
+ : +---------------+ :
+ : :
+ : dispatch values :
+ + - - - - - - - - - +
+
+After the values are passed from the "read" plugins to the dispatch functions,
+the pre-cache chain is run first. The values are added to the internal cache
+afterwards. The post-cache chain is run after the values have been added to the
+cache. So why is it such a huge deal if chains are run before or after the
+values have been added to this cache?
+
+Targets that change the identifier of a value list should be executed before
+the values are added to the cache, so that the name in the cache matches the
+name that is used in the "write" plugins. The C<unixsock> plugin, too, uses
+this cache to receive a list of all available values. If you change the
+identifier after the value list has been added to the cache, this may easily
+lead to confusion, but it's not forbidden of course.
+
+The cache is also used to convert counter values to rates. These rates are, for
+example, used by the C<value> match (see below). If you use the rate stored in
+the cache B<before> the new value is added, you will use the old, B<previous>
+rate. Write plugins may use this rate, too, see the C<csv> plugin, for example.
+The C<unixsock> plugin uses these rates too, to implement the C<GETVAL>
+command.
+
+Last but not last, the B<stop> target makes a difference: If the pre-cache
+chain returns the stop condition, the value will not be added to the cache and
+the post-cache chain will not be run.
+
+=item B<Chain> I<Name>
+
+Adds a new chain with a certain name. This name can be used to refer to a
+specific chain, for example to jump to it.
+
+Within the B<Chain> block, there can be B<Rule> blocks and B<Target> blocks.
+
+=item B<Rule> [I<Name>]
+
+Adds a new rule to the current chain. The name of the rule is optional and
+currently has no meaning for the daemon.
+
+Within the B<Rule> block, there may be any number of B<Match> blocks and there
+must be at least one B<Target> block.
+
+=item B<Match> I<Name>
+
+Adds a match to a B<Rule> block. The name specifies what kind of match should
+be performed. Available matches depend on the plugins that have been loaded.
+
+The arguments inside the B<Match> block are passed to the plugin implementing
+the match, so which arguments are valid here depends on the plugin being used.
+If you do not need any to pass any arguments to a match, you can use the
+shorter syntax:
+
+ Match "foobar"
+
+Which is equivalent to:
+
+ <Match "foobar">
+ </Match>
+
+=item B<Target> I<Name>
+
+Add a target to a rule or a default target to a chain. The name specifies what
+kind of target is to be added. Which targets are available depends on the
+plugins being loaded.
+
+The arguments inside the B<Target> block are passed to the plugin implementing
+the target, so which arguments are valid here depends on the plugin being used.
+If you do not need any to pass any arguments to a target, you can use the
+shorter syntax:
+
+ Target "stop"
+
+This is the same as writing:
+
+ <Target "stop">
+ </Target>
+
+=back
+
+=head2 Built-in targets
+
+The following targets are built into the core daemon and therefore need no
+plugins to be loaded:
+
+=over 4
+
+=item B<return>
+
+Signals the "return" condition, see the L<"Flow control"> section above. This
+causes the current chain to stop processing the value and returns control to
+the calling chain. The calling chain will continue processing targets and rules
+just after the B<jump> target (see below). This is very similar to the
+B<RETURN> target of iptables, see L<iptables(8)>.
+
+This target does not have any options.
+
+Example:
+
+ Target "return"
+
+=item B<stop>
+
+Signals the "stop" condition, see the L<"Flow control"> section above. This
+causes processing of the value to be aborted immediately. This is similar to
+the B<DROP> target of iptables, see L<iptables(8)>.
+
+This target does not have any options.
+
+Example:
+
+ Target "stop"
+
+=item B<write>
+
+Sends the value to "write" plugins.
+
+Available options:
+
+=over 4
+
+=item B<Plugin> I<Name>
+
+Name of the write plugin to which the data should be sent. This option may be
+given multiple times to send the data to more than one write plugin.
+
+=back
+
+If no plugin is explicitly specified, the values will be sent to all available
+write plugins.
+
+Example:
+
+ <Target "write">
+ Plugin "rrdtool"
+ </Target>
+
+=item B<jump>
+
+Starts processing the rules of another chain, see L<"Flow control"> above. If
+the end of that chain is reached, or a stop condition is encountered,
+processing will continue right after the B<jump> target, i.E<nbsp>e. with the
+next target or the next rule. This is similar to the B<-j> command line option
+of iptables, see L<iptables(8)>.
+
+Available options:
+
+=over 4
+
+=item B<Chain> I<Name>
+
+Jumps to the chain I<Name>. This argument is required and may appear only once.
+
+=back
+
+Example:
+
+ <Target "jump">
+ Chain "foobar"
+ </Target>
+
+=back
+
+=head2 Available matches
+
+=over 4
+
+=item B<regex>
+
+Matches a value using regular expressions.
+
+Available options:
+
+=over 4
+
+=item B<Host> I<Regex>
+
+=item B<Plugin> I<Regex>
+
+=item B<PluginInstance> I<Regex>
+
+=item B<Type> I<Regex>
+
+=item B<TypeInstance> I<Regex>
+
+Match values where the given regular expressions match the various fields of
+the identifier of a value. If multiple regular expressions are given, B<all>
+regexen must match for a value to match.
+
+=back
+
+Example:
+
+ <Match "regex">
+ Host "customer[0-9]+"
+ Plugin "^foobar$"
+ </Match>
+
+=item B<timediff>
+
+Matches values that have a time which differs from the time on the server.
+
+This match is mainly intended for servers that receive values over the
+C<network> plugin and write them to disk using the C<rrdtool> plugin. RRDtool
+is very sensitive to the timestamp used when updating the RRD files. In
+particular, the time must be ever increasing. If a misbehaving client sends one
+packet with a timestamp far in the future, all further packets with a correct
+time will be ignored because of that one packet. What's worse, such corrupted
+RRD files are hard to fix.
+
+This match lets one match all values B<outside> a specified time range
+(relative to the server's time), so you can use the B<stop> target (see below)
+to ignore the value, for example.
+
+Available options:
+
+=over 4
+
+=item B<Future> I<Seconds>
+
+Matches all values that are I<ahead> of the server's time by I<Seconds> or more
+seconds. Set to zero for no limit. Either B<Future> or B<Past> must be
+non-zero.
+
+=item B<Past> I<Seconds>
+
+Matches all values that are I<behind> of the server's time by I<Seconds> or
+more seconds. Set to zero for no limit. Either B<Future> or B<Past> must be
+non-zero.
+
+=back
+
+Example:
+
+ <Match "timediff">
+ Future 300
+ Past 3600
+ </Match>
+
+This example matches all values that are five minutes or more ahead of the
+server or one hour (or more) lagging behind.
+
+=item B<value>
+
+Matches the actual value of data sources against given minimumE<nbsp>/ maximum
+values. If a data-set consists of more than one data-source, all data-sources
+must match the specified ranges for a positive match.
+
+Available options:
+
+=over 4
+
+=item B<Min> I<Value>
+
+Sets the smallest value which still results in a match. If unset, behaves like
+negative infinity.
+
+=item B<Max> I<Value>
+
+Sets the largest value which still results in a match. If unset, behaves like
+positive infinity.
+
+=item B<Invert> B<true>|B<false>
+
+Inverts the selection. If the B<Min> and B<Max> settings result in a match,
+no-match is returned and vice versa. Please note that the B<Invert> setting
+only effects how B<Min> and B<Max> are applied to a specific value. Especially
+the B<DataSource> and B<Satisfy> settings (see below) are not inverted.
+
+=item B<DataSource> I<DSName> [I<DSName> ...]
+
+Select one or more of the data sources. If no data source is configured, all
+data sources will be checked. If the type handled by the match does not have a
+data source of the specified name(s), this will always result in no match
+(independent of the B<Invert> setting).
+
+=item B<Satisfy> B<Any>|B<All>
+
+Specifies how checking with several data sources is performed. If set to
+B<Any>, the match succeeds if one of the data sources is in the configured
+range. If set to B<All> the match only succeeds if all data sources are within
+the configured range. Default is B<All>.
+
+Usually B<All> is used for positive matches, B<Any> is used for negative
+matches. This means that with B<All> you usually check that all values are in a
+"good" range, while with B<Any> you check if any value is within a "bad" range
+(or outside the "good" range).
+
+=back
+
+Either B<Min> or B<Max>, but not both, may be unset.
+
+Example:
+
+ # Match all values smaller than or equal to 100. Matches only if all data
+ # sources are below 100.
+ <Match "value">
+ Max 100
+ Satisfy "All"
+ </Match>
+
+ # Match if the value of any data source is outside the range of 0 - 100.
+ <Match "value">
+ Min 0
+ Max 100
+ Invert true
+ Satisfy "Any"
+ </Match>
+
+=back
+
+=head2 Available targets
+
+=over 4
+
+=item B<notification>
+
+Creates and dispatches a notification.
+
+Available options:
+
+=over 4
+
+=item B<Message> I<String>
+
+This required option sets the message of the notification. The following
+placeholders will be replaced by an appropriate value:
+
+=over 4
+
+=item B<%{host}>
+
+=item B<%{plugin}>
+
+=item B<%{plugin_instance}>
+
+=item B<%{type}>
+
+=item B<%{type_instance}>
+
+These placeholders are replaced by the identifier field of the same name.
+
+=item B<%{ds:>I<name>B<}>
+
+These placeholders are replaced by a (hopefully) human readable representation
+of the current rate of this data source. If you changed the instance name
+(using the B<set> or B<replace> targets, see below), it may not be possible to
+convert counter values to rates.
+
+=back
+
+Please note that these placeholders are B<case sensitive>!
+
+=item B<Severity> B<"FATAL">|B<"WARNING">|B<"OKAY">
+
+Sets the severity of the message. If omitted, the severity B<"WARNING"> is
+used.
+
+=back
+
+Example:
+
+ <Target "notification">
+ Message "Oops, the %{type_instance} temperature is currently %{ds:value}!"
+ Severity "WARNING"
+ </Target>
+
+=item B<replace>
+
+Replaces parts of the identifier using regular expressions.
+
+Available options:
+
+=over 4
+
+=item B<Host> I<Regex> I<Replacement>
+
+=item B<Plugin> I<Regex> I<Replacement>
+
+=item B<PluginInstance> I<Regex> I<Replacement>
+
+=item B<TypeInstance> I<Regex> I<Replacement>
+
+Match the appropriate field with the given regular expression I<Regex>. If the
+regular expression matches, that part that matches is replaced with
+I<Replacement>. If multiple places of the input buffer match a given regular
+expression, only the first occurrence will be replaced.
+
+You can specify each option multiple times to use multiple regular expressions
+one after another.
+
+=back
+
+Example:
+
+ <Target "replace">
+ # Replace "example.net" with "example.com"
+ Host "\\<example.net\\>" "example.com"
+
+ # Strip "www." from hostnames
+ Host "\\<www\\." ""
+ </Target>
+
+=item B<set>
+
+Sets part of the identifier of a value to a given string.
+
+Available options:
+
+=over 4
+
+=item B<Host> I<String>
+
+=item B<Plugin> I<String>
+
+=item B<PluginInstance> I<String>
+
+=item B<TypeInstance> I<String>
+
+Set the appropriate field to the given string. The strings for plugin instance
+and type instance may be empty, the strings for host and plugin may not be
+empty. It's currently not possible to set the type of a value this way.
+
+=back
+
+Example:
+
+ <Target "set">
+ PluginInstance "coretemp"
+ TypeInstance "core3"
+ </Target>
+
+=back
+
+=head2 Backwards compatibility
+
+If you use collectd with an old configuration, i.E<nbsp>e. one without a
+B<Chain> block, it will behave as it used to. This is equivalent to the
+following configuration:
+
+ <Chain "PostCache">
+ Target "write"
+ </Chain>
+
+If you specify a B<PostCacheChain>, the B<write> target will not be added
+anywhere and you will have to make sure that it is called where appropriate. We
+suggest to add the above snippet as default target to your "PostCache" chain.
+
+=head2 Examples
+
+Ignore all values, where the hostname does not contain a dot, i.E<nbsp>e. can't
+be an FQDN.
+
+ <Chain "PreCache">
+ <Rule "no_fqdn">
+ <Match "regex">
+ Host "^[^\.]*$"
+ </Match>
+ Target "stop"
+ </Rule>
+ Target "write"
+ </Chain>
+
=head1 SEE ALSO
L<collectd(1)>,
L<collectd-unixsock(5)>,
L<types.db(5)>,
L<hddtemp(8)>,
+L<iptables(8)>,
L<kstat(3KSTAT)>,
L<mbmon(1)>,
L<psql(1)>,
+L<regex(7)>,
L<rrdtool(1)>,
L<sensors(1)>
projects / collectd.git / blobdiff