=encoding UTF-8

=head1 NAME

collectd-snmp - Documentation of collectd's C<snmp plugin>

=head1 SYNOPSIS

  LoadPlugin snmp
  # ...
  <Plugin snmp>
    <Data "powerplus_voltge_input">
      Table false
      Type "voltage"
      TypeInstance "input_line1"
      Scale 0.1
      Values "SNMPv2-SMI::enterprises.6050.5.4.1.1.2.1"
    </Data>
    <Data "hr_users">
      Table false
      Type "users"
      Shift -1
      Values "HOST-RESOURCES-MIB::hrSystemNumUsers.0"
    </Data>
    <Data "std_traffic">
      Table true
      Type "if_octets"
      TypeInstanceOID "IF-MIB::ifDescr"
      #FilterOID "IF-MIB::ifOperStatus"
      #FilterValues "1", "2"
      Values "IF-MIB::ifInOctets" "IF-MIB::ifOutOctets"
    </Data>

    <Host "some.switch.mydomain.org">
      Address "192.168.0.2"
      Version 1
      Community "community_string"
      Collect "std_traffic"
      Interval 120
      Timeout 10
      Retries 1
    </Host>
    <Host "some.server.mydomain.org">
      Address "192.168.0.42"
      Version 2
      Community "another_string"
      Collect "std_traffic" "hr_users"
    </Host>
    <Host "secure.router.mydomain.org">
      Address "192.168.0.7:165"
      Version 3
      SecurityLevel "authPriv"
      Username "cosmo"
      AuthProtocol "SHA"
      AuthPassphrase "setec_astronomy"
      PrivacyProtocol "AES"
      PrivacyPassphrase "too_many_secrets"
      Collect "std_traffic"
    </Host>
    <Host "some.ups.mydomain.org">
      Address "tcp:192.168.0.3"
      Version 1
      Community "more_communities"
      Collect "powerplus_voltge_input"
      Interval 300
      Timeout 5
      Retries 5
    </Host>
  </Plugin>

=head1 DESCRIPTION

The C<snmp plugin> queries other hosts using SNMP, the simple network
management protocol, and translates the value it receives to collectd's
internal format and dispatches them. Depending on the write plugins you have
loaded they may be written to disk or submitted to another instance or
whatever you configured.

Because querying a host via SNMP may produce a timeout the "complex reads"
polling method is used. The ReadThreads parameter in the main configuration
influences the number of parallel polling jobs which can be undertaken. If
you expect timeouts or some polling to take a long time, you should increase
this parameter. Note that other plugins also use the same threads.

=head1 CONFIGURATION

Since the aim of the C<snmp plugin> is to provide a generic interface to SNMP,
its configuration is not trivial and may take some time.

Since the C<Net-SNMP> library is used you can use all the environment variables
that are interpreted by that package. See L<snmpcmd(1)> for more details.

There are two types of blocks that can be contained in the
C<E<lt>PluginE<nbsp>snmpE<gt>> block: B<Data> and B<Host>:

=head2 The B<Data> block

The B<Data> block defines a list of values or a table of values that are to be
queried. The following options can be set:

=over 4

=item B<Type> I<type>

collectd's type that is to be used, e.E<nbsp>g. "if_octets" for interface
traffic or "users" for a user count. The types are read from the B<TypesDB>
(see L<collectd.conf(5)>), so you may want to check for which types are
defined. See L<types.db(5)> for a description of the format of this file.

=item B<Table> I<true|false>

Define if this is a single list of values or a table of values. The difference
is the following:

When B<Table> is set to B<false>, the OIDs given to B<Values> (see below) are
queried using the C<GET> SNMP command (see L<snmpget(1)>) and transmitted to
collectd. B<One> value list is dispatched and, eventually, one file will be
written.

When B<Table> is set to B<true>, the OIDs given to B<Values>, B<TypeInstanceOID>,
B<PluginInstanceOID>, B<HostOID> and B<FilterOID> (see below) are queried using
the C<GETNEXT> SNMP command until the subtree is left. After all
the lists (think: all columns of the table) have been read B<several> values
sets will be dispatches and, eventually, several files will be written. If you
configure a B<Type> (see above) which needs more than one data source (for
example C<if_octets> which needs C<rx> and C<tx>) you will need to specify more
than one (two, in the example case) OIDs with the B<Values> option. This has
nothing to do with the B<Table> setting.

For example, if you want to query the number of users on a system, you can use
C<HOST-RESOURCES-MIB::hrSystemNumUsers.0>. This is one value and belongs to one
value list, therefore B<Table> must be set to B<false>. Please note that, in
this case, you have to include the sequence number (zero in this case) in the
OID.

Counter example: If you want to query the interface table provided by the
C<IF-MIB>, e.E<nbsp>g. the bytes transmitted. There are potentially many
interfaces, so you will want to set B<Table> to B<true>. Because the
C<if_octets> type needs two values, received and transmitted bytes, you need to
specify two OIDs in the B<Values> setting, in this case likely
C<IF-MIB::ifHCInOctets> and C<IF-MIB::ifHCOutOctets>. But, this is because of
the B<Type> setting, not the B<Table> setting.

Since the semantic of B<Instance> and B<Values> depends on this setting you
need to set it before setting them. Doing vice versa will result in undefined
behavior.

=item B<Plugin> I<Plugin>

Use I<Plugin> as the plugin name of the values that are dispatched.
Defaults to C<snmp>.

=item B<PluginInstance> I<Instance>

Sets the plugin-instance of the values that are dispatched to I<Instance> value.

When B<Table> is set to I<true> and B<PluginInstanceOID> is set then this option
has no effect.

Defaults to an empty string.

=item B<TypeInstance> I<Instance>

Sets the type-instance of the values that are dispatched to I<Instance> value.

When B<Table> is set to I<true> and B<TypeInstanceOID> is set then this option
has no effect.

Defaults to an empty string.

=item B<TypeInstanceOID> I<OID>

=item B<PluginInstanceOID> I<OID>

=item B<HostOID> I<OID>

If B<Table> is set to I<true>, I<OID> is interpreted as an SNMP-prefix that will
return a list of values. Those values are then used as the actual type-instance,
plugin-instance or host of dispatched metrics. An example would be the
C<IF-MIB::ifDescr> subtree. L<variables(5)> from the SNMP distribution describes
the format of OIDs. When option is set to empty string, then "SUBID" will be used
as the value.

Prefix may be set for values with use of appropriate B<TypeInstancePrefix>,
B<PluginInstancePrefix> and B<HostPrefix> options.

When B<Table> is set to I<false> these options has no effect.

Defaults: When no one of these options is configured explicitly,
B<TypeInstanceOID> defaults to an empty string.

=item B<TypeInstancePrefix>

=item B<PluginInstancePrefix>

=item B<HostPrefix>

These options are intented to be used together with B<TypeInstanceOID>,
B<PluginInstanceOID> and B<HostOID> respectively.

If set, I<String> is preprended to values received by querying the agent.

When B<Table> is set to I<false> these options has no effect.

The C<UPS-MIB> is an example where you need this setting: It has voltages of
the inlets, outlets and the battery of an UPS. However, it doesn't provide a
descriptive column for these voltages. In this case having 1, 2,E<nbsp>... as
instances is not enough, because the inlet voltages and outlet voltages may
both have the subids 1, 2,E<nbsp>... You can use this setting to distinguish
between the different voltages.

=item B<Instance> I<Instance>

Attention: this option exists for backwards compatibility only and will be
removed in next major release. Please use B<TypeInstance> / B<TypeInstanceOID>
instead.

The meaning of this setting depends on whether B<Table> is set to I<true> or
I<false>.

If B<Table> is set to I<true>, option behaves as B<TypeInstanceOID>.
If B<Table> is set to I<false>, option behaves as B<TypeInstance>.

Note what B<Table> option must be set before setting B<Instance>.

=item B<InstancePrefix> I<String>

Attention: this option exists for backwards compatibility only and will be
removed in next major release. Please use B<TypeInstancePrefix> instead.

=item B<Values> I<OID> [I<OID> ...]

Configures the values to be queried from the SNMP host. The meaning slightly
changes with the B<Table> setting. L<variables(5)> from the SNMP distribution
describes the format of OIDs.

If B<Table> is set to I<true>, each I<OID> must be the prefix of all the
values to query, e.E<nbsp>g. C<IF-MIB::ifInOctets> for all the counters of
incoming traffic. This subtree is walked (using C<GETNEXT>) until a value from
outside the subtree is returned.

If B<Table> is set to I<false>, each I<OID> must be the OID of exactly one
value, e.E<nbsp>g. C<IF-MIB::ifInOctets.3> for the third counter of incoming
traffic.

=item B<Scale> I<Value>

The gauge-values returned by the SNMP-agent are multiplied by I<Value>.  This
is useful when values are transferred as a fixed point real number. For example,
thermometers may transfer B<243> but actually mean B<24.3>, so you can specify
a scale value of B<0.1> to correct this. The default value is, of course,
B<1.0>.

This value is not applied to counter-values.

=item B<Shift> I<Value>

I<Value> is added to gauge-values returned by the SNMP-agent after they have
been multiplied by any B<Scale> value. If, for example, a thermometer returns
degrees Kelvin you could specify a shift of B<273.15> here to store values in
degrees Celsius. The default value is, of course, B<0.0>.

This value is not applied to counter-values.

=item B<Ignore> I<Value> [, I<Value> ...]

The ignore values allows one to ignore TypeInstances based on their name and
the patterns specified by the various values you've entered. The match is a
glob-type shell matching.

When B<Table> is set to I<false> then this option has no effect.

=item B<InvertMatch> I<true|false(default)>

The invertmatch value should be use in combination of the Ignore option.
It changes the behaviour of the Ignore option, from a blacklist behaviour
when InvertMatch is set to false, to a whitelist when specified to true.

=item B<FilterOID> I<OID>

=item B<FilterValues> I<Value> [, I<Value> ...]

=item B<FilterIgnoreSelected> I<true|false(default)>

When B<Table> is set to I<true>, these options allow to configure filtering
based on MIB values.

The B<FilterOID> declares I<OID> to fill table column with values.
The B<FilterValues> declares values list to do match. Whether table row will be
collected or ignored depends on the B<FilterIgnoreSelected> setting.
As with other plugins that use the daemon's ignorelist functionality, a string
that starts and ends with a slash is interpreted as a regular expression.

If no selection is configured at all, B<all> table rows are selected.

When B<Table> is set to I<false> then these options has no effect.

See B<Table> and F</"IGNORELISTS"> for details.

=back

=head2 The Host block

The B<Host> block defines which hosts to query, which SNMP community and
version to use and which of the defined B<Data> to query.

The argument passed to the B<Host> block is used as the hostname in the data
stored by collectd.

=over 4

=item B<Address> I<IP-Address>|I<Hostname>

Set the address to connect to. Address may include transport specifier and/or
port number.

=item B<Version> B<1>|B<2>|B<3>

Set the SNMP version to use. When giving B<2> version C<2c> is actually used.

=item B<Community> I<Community>

Pass I<Community> to the host. (Ignored for SNMPv3).

=item B<Username> I<Username>

Sets the I<Username> to use for SNMPv3 security.

=item B<SecurityLevel> I<authPriv>|I<authNoPriv>|I<noAuthNoPriv>

Selects the security level for SNMPv3 security.

=item B<Context> I<Context>

Sets the I<Context> for SNMPv3 security.

=item B<AuthProtocol> I<MD5>|I<SHA>

Selects the authentication protocol for SNMPv3 security.

=item B<AuthPassphrase> I<Passphrase>

Sets the authentication passphrase for SNMPv3 security.

=item B<PrivacyProtocol> I<AES>|I<DES>

Selects the privacy (encryption) protocol for SNMPv3 security.

=item B<PrivacyPassphrase> I<Passphrase>

Sets the privacy (encryption) passphrase for SNMPv3 security.

=item B<Collect> I<Data> [I<Data> ...]

Defines which values to collect. I<Data> refers to one of the B<Data> block
above. Since the config file is read top-down you need to define the data
before using it here.

=item B<Interval> I<Seconds>

Collect data from this host every I<Seconds> seconds. This option is meant for
devices with not much CPU power, e.E<nbsp>g. network equipment such as
switches, embedded devices, rack monitoring systems and so on. Since the
B<Step> of generated RRD files depends on this setting it's wise to select a
reasonable value once and never change it.

=item B<Timeout> I<Seconds>

How long to wait for a response. The C<Net-SNMP> library default is 1 second.

=item B<Retries> I<Integer>

The number of times that a query should be retried after the Timeout expires.
The C<Net-SNMP> library default is 5.

=back

=head1 SEE ALSO

L<collectd(1)>,
L<collectd.conf(5)>,
L<snmpget(1)>,
L<snmpgetnext(1)>,
L<variables(5)>,
L<unix(7)>

=head1 AUTHORS

Florian Forster E<lt>octo@collectd.orgE<gt>
Michael Pilat E<lt>mike@mikepilat.comE<gt>

=cut