=head2 Plugin C<amqp>
-The I<AMQMP plugin> can be used to communicate with other instances of
+The I<AMQP plugin> can be used to communicate with other instances of
I<collectd> or third party applications using an AMQP message broker. Values
are sent to or received from the broker, which handles routing, queueing and
-possibly filtering or messages.
+possibly filtering out messages.
+
+B<Synopsis:>
<Plugin "amqp">
# Send values to an AMQP broker
</Query>
<Database "product_information">
Driver "mysql"
+ Interval 120
DriverOption "host" "localhost"
DriverOption "username" "collectd"
DriverOption "password" "aZo6daiw"
=over 4
+=item B<Interval> I<Interval>
+
+Sets the interval (in seconds) in which the values will be collected from this
+database. By default the global B<Interval> setting will be used.
+
=item B<Driver> I<Driver>
Specifies the driver to use to connect to the database. In many cases those
=head2 Plugin C<fhcount>
The C<fhcount> plugin provides statistics about used, unused and total number of
-file handles.
+file handles on Linux.
The I<fhcount plugin> provides the following configuration options:
=back
+=head2 Plugin C<mqtt>
+
+The I<MQTT plugin> can send metrics to MQTT (B<Publish> blocks) and receive
+values from MQTT (B<Subscribe> blocks).
+
+B<Synopsis:>
+
+ <Plugin mqtt>
+ <Publish "name">
+ Host "mqtt.example.com"
+ Prefix "collectd"
+ </Publish>
+ <Subscribe "name">
+ Host "mqtt.example.com"
+ Topic "collectd/#"
+ </Subscribe>
+ </Plugin>
+
+The plugin's configuration is in B<Publish> and/or B<Subscribe> blocks,
+configuring the sending and receiving direction respectively. The plugin will
+register a write callback named C<mqtt/I<name>> where I<name> is the string
+argument given to the B<Publish> block. Both types of blocks share many but not
+all of the following options. If an option is valid in only one of the blocks,
+it will be mentioned explicitly.
+
+B<Options:>
+
+=over 4
+
+=item B<Host> I<Hostname>
+
+Hostname of the MQTT broker to connect to.
+
+=item B<Port> I<Service>
+
+Port number or service name of the MQTT broker to connect to.
+
+=item B<User> I<UserName>
+
+Username used when authenticating to the MQTT broker.
+
+=item B<Password> I<Password>
+
+Password used when authenticating to the MQTT broker.
+
+=item B<ClientId> I<ClientId>
+
+MQTT client ID to use. Defaults to the hostname used by I<collectd>.
+
+=item B<QoS> [B<0>-B<2>]
+
+Sets the I<Quality of Service>, with the values C<0>, C<1> and C<2> meaning:
+
+=over 4
+
+=item B<0>
+
+At most once
+
+=item B<1>
+
+At least once
+
+=item B<2>
+
+Exactly once
+
+=back
+
+In B<Publish> blocks, this option determines the QoS flag set on outgoing
+messages and defaults to B<0>. In B<Subscribe> blocks, determines the maximum
+QoS setting the client is going to accept and defaults to B<2>. If the QoS flag
+on a message is larger than the maximum accepted QoS of a subscriber, the
+message's QoS will be downgraded.
+
+=item B<Prefix> I<Prefix> (Publish only)
+
+This plugin will use one topic per I<value list> which will looks like a path.
+I<Prefix> is used as the first path element and defaults to B<collectd>.
+
+An example topic name would be:
+
+ collectd/cpu-0/cpu-user
+
+=item B<Retain> B<false>|B<true> (Publish only)
+
+Controls whether the MQTT broker will retain (keep a copy of) the last message
+sent to each topic and deliver it to new subscribers. Defaults to B<false>.
+
+=item B<StoreRates> B<true>|B<false> (Publish only)
+
+Controls whether C<DERIVE> and C<COUNTER> metrics are converted to a I<rate>
+before sending. Defaults to B<true>.
+
+=item B<CleanSession> B<true>|B<false> (Subscribe only)
+
+Controls whether the MQTT "cleans" the session up after the subscriber
+disconnects or if it maintains the subscriber's subscriptions and all messages
+that arrive while the subscriber is disconnected. Defaults to B<true>.
+
+=item B<Topic> I<TopicName> (Subscribe only)
+
+Configures the topic(s) to subscribe to. You can use the single level C<+> and
+multi level C<#> wildcards. Defaults to B<collectd/#>, i.e. all topics beneath
+the B<collectd> branch.
+
+=item B<CACert> I<file>
+
+Path to the PEM-encoded CA certificate file. Setting this option enables TLS
+communication with the MQTT broker, and as such, B<Port> should be the TLS-enabled
+port of the MQTT broker.
+A valid TLS configuration requires B<CACert>, B<CertificateFile> and B<CertificateKeyFile>.
+
+=item B<CertificateFile> I<file>
+
+Path to the PEM-encoded certificate file to use as client certificate when
+connecting to the MQTT broker.
+A valid TLS configuration requires B<CACert>, B<CertificateFile> and B<CertificateKeyFile>.
+
+=item B<CertificateKeyFile> I<file>
+
+Path to the unencrypted PEM-encoded key file corresponding to B<CertificateFile>.
+A valid TLS configuration requires B<CACert>, B<CertificateFile> and B<CertificateKeyFile>.
+
+=item B<TLSProtocol> I<protocol>
+
+If configured, this specifies the string protocol version (e.g. C<tlsv1>,
+C<tlsv1.2>) to use for the TLS connection to the broker. If not set a default
+version is used which depends on the version of OpenSSL the Mosquitto library
+was linked against.
+
+=item B<CipherSuite> I<ciphersuite>
+
+A string describing the ciphers available for use. See L<ciphers(1)> and the
+C<openssl ciphers> utility for more information. If unset, the default ciphers
+will be used.
+
+
+=back
+
=head2 Plugin C<mysql>
The C<mysql plugin> requires B<mysqlclient> to be installed. It connects to
means to concatenate the guest name and UUID (with a literal colon character
between, thus I<"foo:1234-1234-1234-1234">).
+At the moment of writing (collectd-5.5), hostname string is limited to 62
+characters. In case when combination of fields exceeds 62 characters,
+hostname will be truncated without a warning.
+
=item B<InterfaceFormat> B<name>|B<address>
When the virt plugin logs interface data, it sets the name of the collected
B<address> means use the interface's mac address. This is useful since the
interface path might change between reboots of a guest or across migrations.
-=item B<PluginInstanceFormat> B<name|uuid>
+=item B<PluginInstanceFormat> B<name|uuid|none>
When the virt plugin logs data, it sets the plugin_instance of the collected
-data according to this setting. The default is to use the guest name as provided
-by the hypervisor, which is equal to setting B<name>.
+data according to this setting. The default is to not set the plugin_instance.
+B<name> means use the guest's name as provided by the hypervisor.
B<uuid> means use the guest's UUID.
+You can also specify combinations of the B<name> and B<uuid> fields.
+For example B<name uuid> means to concatenate the guest name and UUID
+(with a literal colon character between, thus I<"foo:1234-1234-1234-1234">).
+
=back
=head2 Plugin C<vmem>
all the data in the current send buffer will probably be lost. Defaults to 0,
which means the connection never times out.
+=item B<LogHttpError> B<false>|B<true>
+
+Enables printing of HTTP error code to log. Turned off by default.
+
The C<write_http> plugin regularly submits the collected values to the HTTP
server. How frequently this happens depends on how much data you are collecting
and the size of B<BufferSize>. The optimal value to set B<Timeout> to is
Port "6379"
Timeout 1000
Prefix "collectd/"
+ Database 1
+ MaxSetSize -1
+ StoreRates true
</Node>
</Plugin>
Values are submitted to I<Sorted Sets>, using the metric name as the key, and
the timestamp as the score. Retrieving a date range can then be done using the
-C<ZRANGEBYSCORE> I<Redis> command. Additionnally, all the identifiers of these
+C<ZRANGEBYSCORE> I<Redis> command. Additionally, all the identifiers of these
I<Sorted Sets> are kept in a I<Set> called C<collectd/values> (or
C<${prefix}/values> if the B<Prefix> option was specified) and can be retrieved
-using the C<SMEMBERS> I<Redis> command. See
+using the C<SMEMBERS> I<Redis> command. You can specify the database to use
+with the B<Database> parameter (default is C<0>). See
L<http://redis.io/commands#sorted_set> and L<http://redis.io/commands#set> for
details.
=item B<Node> I<Nodename>
The B<Node> block identifies a new I<Redis> node, that is a new I<Redis>
-instance running in an specified host and port. The name for node is a
+instance running on a specified host and port. The node name is a
canonical identifier which is used as I<plugin instance>. It is limited to
-64E<nbsp>characters in length.
+51E<nbsp>characters in length.
=item B<Host> I<Hostname>
like C<collectd/cpu-0/cpu-user>. When setting this to something different, it
is recommended but not required to include a trailing slash in I<Prefix>.
+=item B<Database> I<Index>
+
+This index selects the redis database to use for writing operations. Defaults
+to C<0>.
+
+=item B<MaxSetSize> I<Items>
+
+The B<MaxSetSize> option limits the number of items that the I<Sorted Sets> can
+hold. Negative values for I<Items> sets no limit, which is the default behavior.
+
+=item B<StoreRates> B<true>|B<false>
+
+If set to B<true> (the default), convert counter values to rates. If set to
+B<false> counter values are stored as is, i.e. as an increasing integer number.
+
=back
=head2 Plugin C<write_riemann>
=item B<AlwaysAppendDS> B<false>|B<true>
-If set the B<true>, append the name of the I<Data Source> (DS) to the
+If set to B<true>, append the name of the I<Data Source> (DS) to the
"service", i.e. the field that, together with the "host" field, uniquely
identifies a metric in I<Riemann>. If set to B<false> (the default), this is
only done when there is more than one DS.