snmp

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Published: Apr 3, 2023 License: MIT Imports: 22 Imported by: 186

README

SNMP Input Plugin

The snmp input plugin uses polling to gather metrics from SNMP agents. Support for gathering individual OIDs as well as complete SNMP tables is included.

Note about Paths

Path is a global variable, separate snmp instances will append the specified path onto the global path variable

Global configuration options

In addition to the plugin-specific configuration settings, plugins support additional global and plugin configuration settings. These settings are used to modify metrics, tags, and field or create aliases and configure ordering, etc. See the CONFIGURATION.md for more details.

SNMP backend: gosmi and netsnmp

Telegraf has two backends to translate SNMP objects. By default, Telegraf will use netsnmp, however, this option is deprecated and it is encouraged that users migrate to gosmi. If users find issues with gosmi that do not occur with netsnmp please open a project issue on GitHub.

The SNMP backend setting is a global-level setting that applies to all use of SNMP in Telegraf. Users can set this option in the [agent] configuration via the snmp_translator option. See the agent configuration for more details.

Configuration

# Retrieves SNMP values from remote agents
[[inputs.snmp]]
  ## Agent addresses to retrieve values from.
  ##   format:  agents = ["<scheme://><hostname>:<port>"]
  ##   scheme:  optional, either udp, udp4, udp6, tcp, tcp4, tcp6.
  ##            default is udp
  ##   port:    optional
  ##   example: agents = ["udp://127.0.0.1:161"]
  ##            agents = ["tcp://127.0.0.1:161"]
  ##            agents = ["udp4://v4only-snmp-agent"]
  agents = ["udp://127.0.0.1:161"]

  ## Timeout for each request.
  # timeout = "5s"

  ## SNMP version; can be 1, 2, or 3.
  # version = 2

  ## Unconnected UDP socket
  ## When true, SNMP reponses are accepted from any address not just
  ## the requested address. This can be useful when gathering from
  ## redundant/failover systems.
  # unconnected_udp_socket = false

  ## Path to mib files
  ## Used by the gosmi translator.
  ## To add paths when translating with netsnmp, use the MIBDIRS environment variable
  # path = ["/usr/share/snmp/mibs"]

  ## SNMP community string.
  # community = "public"

  ## Agent host tag
  # agent_host_tag = "agent_host"

  ## Number of retries to attempt.
  # retries = 3

  ## The GETBULK max-repetitions parameter.
  # max_repetitions = 10

  ## SNMPv3 authentication and encryption options.
  ##
  ## Security Name.
  # sec_name = "myuser"
  ## Authentication protocol; one of "MD5", "SHA", "SHA224", "SHA256", "SHA384", "SHA512" or "".
  # auth_protocol = "MD5"
  ## Authentication password.
  # auth_password = "pass"
  ## Security Level; one of "noAuthNoPriv", "authNoPriv", or "authPriv".
  # sec_level = "authNoPriv"
  ## Context Name.
  # context_name = ""
  ## Privacy protocol used for encrypted messages; one of "DES", "AES", "AES192", "AES192C", "AES256", "AES256C", or "".
  ### Protocols "AES192", "AES192", "AES256", and "AES256C" require the underlying net-snmp tools
  ### to be compiled with --enable-blumenthal-aes (http://www.net-snmp.org/docs/INSTALL.html)
  # priv_protocol = ""
  ## Privacy password used for encrypted messages.
  # priv_password = ""

  ## Add fields and tables defining the variables you wish to collect.  This
  ## example collects the system uptime and interface variables.  Reference the
  ## full plugin documentation for configuration details.
  [[inputs.snmp.field]]
    oid = "RFC1213-MIB::sysUpTime.0"
    name = "uptime"

  [[inputs.snmp.field]]
    oid = "RFC1213-MIB::sysName.0"
    name = "source"
    is_tag = true

  [[inputs.snmp.table]]
    oid = "IF-MIB::ifTable"
    name = "interface"
    inherit_tags = ["source"]

    [[inputs.snmp.table.field]]
      oid = "IF-MIB::ifDescr"
      name = "ifDescr"
      is_tag = true
Configure SNMP Requests

This plugin provides two methods for configuring the SNMP requests: fields and tables. Use the field option to gather single ad-hoc variables. To collect SNMP tables, use the table option.

Field

Use a field to collect a variable by OID. Requests specified with this option operate similar to the snmpget utility.

[[inputs.snmp]]
  # ... snip ...

  [[inputs.snmp.field]]
    ## Object identifier of the variable as a numeric or textual OID.
    oid = "RFC1213-MIB::sysName.0"

    ## Name of the field or tag to create.  If not specified, it defaults to
    ## the value of 'oid'. If 'oid' is numeric, an attempt to translate the
    ## numeric OID into a textual OID will be made.
    # name = ""

    ## If true the variable will be added as a tag, otherwise a field will be
    ## created.
    # is_tag = false

    ## Apply one of the following conversions to the variable value:
    ##   float(X):    Convert the input value into a float and divides by the
    ##                Xth power of 10. Effectively just moves the decimal left
    ##                X places. For example a value of `123` with `float(2)`
    ##                will result in `1.23`.
    ##   float:       Convert the value into a float with no adjustment. Same
    ##                as `float(0)`.
    ##   int:         Convert the value into an integer.
    ##   hwaddr:      Convert the value to a MAC address.
    ##   ipaddr:      Convert the value to an IP address.
    ##   hextoint:X:Y Convert a hex string value to integer. Where X is the Endian
    ##                and Y the bit size. For example: hextoint:LittleEndian:uint64
    ##                or hextoint:BigEndian:uint32. Valid options for the Endian are:
    ##                BigEndian and LittleEndian. For the bit size: uint16, uint32
    ##                and uint64.
    ##   enum(1):     Convert the value according to its syntax in the MIB (full).
    ##                (Only supported with gosmi translator)
    ##   enum:        Convert the value according to its syntax in the MIB.
    ##                (Only supported with gosmi translator)
    ##
    # conversion = ""
Table

Use a table to configure the collection of a SNMP table. SNMP requests formed with this option operate similarly way to the snmptable command.

Control the handling of specific table columns using a nested field. These nested fields are specified similarly to a top-level field.

By default all columns of the SNMP table will be collected - it is not required to add a nested field for each column, only those which you wish to modify. To only collect certain columns, omit the oid from the table section and only include oid settings in field sections. For more complex include/exclude cases for columns use metric filtering.

One metric is created for each row of the SNMP table.

[[inputs.snmp]]
  # ... snip ...

  [[inputs.snmp.table]]
    ## Object identifier of the SNMP table as a numeric or textual OID.
    oid = "IF-MIB::ifTable"

    ## Name of the field or tag to create.  If not specified, it defaults to
    ## the value of 'oid'.  If 'oid' is numeric an attempt to translate the
    ## numeric OID into a textual OID will be made.
    # name = ""

    ## Which tags to inherit from the top-level config and to use in the output
    ## of this table's measurement.
    ## example: inherit_tags = ["source"]
    # inherit_tags = []

    ## Add an 'index' tag with the table row number.  Use this if the table has
    ## no indexes or if you are excluding them.  This option is normally not
    ## required as any index columns are automatically added as tags.
    # index_as_tag = false

    [[inputs.snmp.table.field]]
      ## OID to get. May be a numeric or textual module-qualified OID.
      oid = "IF-MIB::ifDescr"

      ## Name of the field or tag to create.  If not specified, it defaults to
      ## the value of 'oid'. If 'oid' is numeric an attempt to translate the
      ## numeric OID into a textual OID will be made.
      # name = ""

      ## Output this field as a tag.
      # is_tag = false

      ## The OID sub-identifier to strip off so that the index can be matched
      ## against other fields in the table.
      # oid_index_suffix = ""

      ## Specifies the length of the index after the supplied table OID (in OID
      ## path segments). Truncates the index after this point to remove non-fixed
      ## value or length index suffixes.
      # oid_index_length = 0

      ## Specifies if the value of given field should be snmptranslated
      ## by default no field values are translated
      # translate = true

      ## Secondary index table allows to merge data from two tables with
      ## different index that this filed will be used to join them. There can
      ## be only one secondary index table.
      # secondary_index_table = false

      ## This field is using secondary index, and will be later merged with
      ## primary index using SecondaryIndexTable. SecondaryIndexTable and
      ## SecondaryIndexUse are exclusive.
      # secondary_index_use = false

      ## Controls if entries from secondary table should be added or not
      ## if joining index is present or not. I set to true, means that join
      ## is outer, and index is prepended with "Secondary." for missing values
      ## to avoid overlaping indexes from both tables. Can be set per field or
      ## globally with SecondaryIndexTable, global true overrides per field false.
      # secondary_outer_join = false
Two Table Join

Snmp plugin can join two snmp tables that have different indexes. For this to work one table should have translation field that return index of second table as value. Examples of such fields are:

  • Cisco portTable with translation field: CISCO-STACK-MIB::portIfIndex, which value is IfIndex from ifTable
  • Adva entityFacilityTable with translation field: ADVA-FSPR7-MIB::entityFacilityOneIndex, which value is IfIndex from ifTable
  • Cisco cpeExtPsePortTable with translation field: CISCO-POWER-ETHERNET-EXT-MIB::cpeExtPsePortEntPhyIndex, which value is index from entPhysicalTable

Such field can be used to translate index to secondary table with secondary_index_table = true and all fields from secondary table (with index pointed from translation field), should have added option secondary_index_use = true. Telegraf cannot duplicate entries during join so translation must be 1-to-1 (not 1-to-many). To add fields from secondary table with index that is not present in translation table (outer join), there is a second option for translation index secondary_outer_join = true.

Example configuration for table joins

CISCO-POWER-ETHERNET-EXT-MIB table before join:

[[inputs.snmp.table]]
name = "ciscoPower"
index_as_tag = true

[[inputs.snmp.table.field]]
name = "PortPwrConsumption"
oid = "CISCO-POWER-ETHERNET-EXT-MIB::cpeExtPsePortPwrConsumption"

[[inputs.snmp.table.field]]
name = "EntPhyIndex"
oid = "CISCO-POWER-ETHERNET-EXT-MIB::cpeExtPsePortEntPhyIndex"

Partial result (removed agent_host and host columns from all following outputs in this section):

> ciscoPower,index=1.2 EntPhyIndex=1002i,PortPwrConsumption=6643i 1621460628000000000
> ciscoPower,index=1.6 EntPhyIndex=1006i,PortPwrConsumption=10287i 1621460628000000000
> ciscoPower,index=1.5 EntPhyIndex=1005i,PortPwrConsumption=8358i 1621460628000000000

Note here that EntPhyIndex column carries index from ENTITY-MIB table, config for it:

[[inputs.snmp.table]]
name = "entityTable"
index_as_tag = true

[[inputs.snmp.table.field]]
name = "EntPhysicalName"
oid = "ENTITY-MIB::entPhysicalName"

Partial result:

> entityTable,index=1006 EntPhysicalName="GigabitEthernet1/6" 1621460809000000000
> entityTable,index=1002 EntPhysicalName="GigabitEthernet1/2" 1621460809000000000
> entityTable,index=1005 EntPhysicalName="GigabitEthernet1/5" 1621460809000000000

Now, lets attempt to join these results into one table. EntPhyIndex matches index from second table, and lets convert EntPhysicalName into tag, so second table will only provide tags into result. Configuration:

[[inputs.snmp.table]]
name = "ciscoPowerEntity"
index_as_tag = true

[[inputs.snmp.table.field]]
name = "PortPwrConsumption"
oid = "CISCO-POWER-ETHERNET-EXT-MIB::cpeExtPsePortPwrConsumption"

[[inputs.snmp.table.field]]
name = "EntPhyIndex"
oid = "CISCO-POWER-ETHERNET-EXT-MIB::cpeExtPsePortEntPhyIndex"
secondary_index_table = true    # enables joining

[[inputs.snmp.table.field]]
name = "EntPhysicalName"
oid = "ENTITY-MIB::entPhysicalName"
secondary_index_use = true      # this tag is indexed from secondary table
is_tag = true

Result:

> ciscoPowerEntity,EntPhysicalName=GigabitEthernet1/2,index=1.2 EntPhyIndex=1002i,PortPwrConsumption=6643i 1621461148000000000
> ciscoPowerEntity,EntPhysicalName=GigabitEthernet1/6,index=1.6 EntPhyIndex=1006i,PortPwrConsumption=10287i 1621461148000000000
> ciscoPowerEntity,EntPhysicalName=GigabitEthernet1/5,index=1.5 EntPhyIndex=1005i,PortPwrConsumption=8358i 1621461148000000000

Troubleshooting

Check that a numeric field can be translated to a textual field:

$ snmptranslate .1.3.6.1.2.1.1.3.0
DISMAN-EVENT-MIB::sysUpTimeInstance

Request a top-level field:

snmpget -v2c -c public 127.0.0.1 sysUpTime.0

Request a table:

snmptable -v2c -c public 127.0.0.1 ifTable

To collect a packet capture, run this command in the background while running Telegraf or one of the above commands. Adjust the interface, host and port as needed:

sudo tcpdump -s 0 -i eth0 -w telegraf-snmp.pcap host 127.0.0.1 and port 161

Metrics

The field and tags will depend on the table and fields configured.

Example Output

snmp,agent_host=127.0.0.1,source=loaner uptime=11331974i 1575509815000000000
interface,agent_host=127.0.0.1,ifDescr=wlan0,ifIndex=3,source=example.org ifAdminStatus=1i,ifInDiscards=0i,ifInErrors=0i,ifInNUcastPkts=0i,ifInOctets=3436617431i,ifInUcastPkts=2717778i,ifInUnknownProtos=0i,ifLastChange=0i,ifMtu=1500i,ifOperStatus=1i,ifOutDiscards=0i,ifOutErrors=0i,ifOutNUcastPkts=0i,ifOutOctets=581368041i,ifOutQLen=0i,ifOutUcastPkts=1354338i,ifPhysAddress="c8:5b:76:c9:e6:8c",ifSpecific=".0.0",ifSpeed=0i,ifType=6i 1575509815000000000
interface,agent_host=127.0.0.1,ifDescr=eth0,ifIndex=2,source=example.org ifAdminStatus=1i,ifInDiscards=0i,ifInErrors=0i,ifInNUcastPkts=21i,ifInOctets=3852386380i,ifInUcastPkts=3634004i,ifInUnknownProtos=0i,ifLastChange=9088763i,ifMtu=1500i,ifOperStatus=1i,ifOutDiscards=0i,ifOutErrors=0i,ifOutNUcastPkts=0i,ifOutOctets=434865441i,ifOutQLen=0i,ifOutUcastPkts=2110394i,ifPhysAddress="c8:5b:76:c9:e6:8c",ifSpecific=".0.0",ifSpeed=1000000000i,ifType=6i 1575509815000000000
interface,agent_host=127.0.0.1,ifDescr=lo,ifIndex=1,source=example.org ifAdminStatus=1i,ifInDiscards=0i,ifInErrors=0i,ifInNUcastPkts=0i,ifInOctets=51555569i,ifInUcastPkts=339097i,ifInUnknownProtos=0i,ifLastChange=0i,ifMtu=65536i,ifOperStatus=1i,ifOutDiscards=0i,ifOutErrors=0i,ifOutNUcastPkts=0i,ifOutOctets=51555569i,ifOutQLen=0i,ifOutUcastPkts=339097i,ifSpecific=".0.0",ifSpeed=10000000i,ifType=24i 1575509815000000000

Documentation

Index

Constants

This section is empty.

Variables

This section is empty.

Functions

func NewGosmiTranslator added in v1.22.0

func NewGosmiTranslator(paths []string, log telegraf.Logger) (*gosmiTranslator, error)

func NewNetsnmpTranslator added in v1.22.0

func NewNetsnmpTranslator() *netsnmpTranslator

Types

type Field added in v1.14.0

type Field struct {
	// Name will be the name of the field.
	Name string
	// OID is prefix for this field. The plugin will perform a walk through all
	// OIDs with this as their parent. For each value found, the plugin will strip
	// off the OID prefix, and use the remainder as the index. For multiple fields
	// to show up in the same row, they must share the same index.
	Oid string
	// OidIndexSuffix is the trailing sub-identifier on a table record OID that will be stripped off to get the record's index.
	OidIndexSuffix string
	// OidIndexLength specifies the length of the index in OID path segments. It can be used to remove sub-identifiers that vary in content or length.
	OidIndexLength int
	// IsTag controls whether this OID is output as a tag or a value.
	IsTag bool
	// Conversion controls any type conversion that is done on the value.
	//  "float"/"float(0)" will convert the value into a float.
	//  "float(X)" will convert the value into a float, and then move the decimal before Xth right-most digit.
	//  "int" will conver the value into an integer.
	//  "hwaddr" will convert a 6-byte string to a MAC address.
	//  "ipaddr" will convert the value to an IPv4 or IPv6 address.
	//  "enum"/"enum(1)" will convert the value according to its syntax. (Only supported with gosmi translator)
	Conversion string
	// Translate tells if the value of the field should be snmptranslated
	Translate bool
	// Secondary index table allows to merge data from two tables with different index
	//  that this filed will be used to join them. There can be only one secondary index table.
	SecondaryIndexTable bool
	// This field is using secondary index, and will be later merged with primary index
	//  using SecondaryIndexTable. SecondaryIndexTable and SecondaryIndexUse are exclusive.
	SecondaryIndexUse bool
	// Controls if entries from secondary table should be added or not if joining
	//  index is present or not. I set to true, means that join is outer, and
	//  index is prepended with "Secondary." for missing values to avoid overlaping
	//  indexes from both tables.
	// Can be set per field or globally with SecondaryIndexTable, global true overrides
	//  per field false.
	SecondaryOuterJoin bool
	// contains filtered or unexported fields
}

Field holds the configuration for a Field to look up.

type RTable added in v1.14.0

type RTable struct {
	// Name is the name of the field, copied from Table.Name.
	Name string
	// Time is the time the table was built.
	Time time.Time
	// Rows are the rows that were found, one row for each table OID index found.
	Rows []RTableRow
}

RTable is the resulting table built from a Table.

type RTableRow added in v1.14.0

type RTableRow struct {
	// Tags are all the Field values which had IsTag=true.
	Tags map[string]string
	// Fields are all the Field values which had IsTag=false.
	Fields map[string]interface{}
}

RTableRow is the resulting row containing all the OID values which shared the same index.

type Snmp

type Snmp struct {
	// The SNMP agent to query. Format is [SCHEME://]ADDR[:PORT] (e.g.
	// udp://1.2.3.4:161).  If the scheme is not specified then "udp" is used.
	Agents []string `toml:"agents"`

	// The tag used to name the agent host
	AgentHostTag string `toml:"agent_host_tag"`

	snmp.ClientConfig

	Tables []Table `toml:"table"`

	// Name & Fields are the elements of a Table.
	// Telegraf chokes if we try to embed a Table. So instead we have to embed the
	// fields of a Table, and construct a Table during runtime.
	Name   string  `toml:"name"`
	Fields []Field `toml:"field"`

	Log telegraf.Logger `toml:"-"`
	// contains filtered or unexported fields
}

Snmp holds the configuration for the plugin.

func (*Snmp) Gather

func (s *Snmp) Gather(acc telegraf.Accumulator) error

Gather retrieves all the configured fields and tables. Any error encountered does not halt the process. The errors are accumulated and returned at the end.

func (*Snmp) Init added in v1.21.0

func (s *Snmp) Init() error

func (*Snmp) SampleConfig

func (*Snmp) SampleConfig() string

func (*Snmp) SetTranslator added in v1.22.0

func (s *Snmp) SetTranslator(name string)

type Table added in v1.14.0

type Table struct {
	// Name will be the name of the measurement.
	Name string

	// Which tags to inherit from the top-level config.
	InheritTags []string

	// Adds each row's table index as a tag.
	IndexAsTag bool

	// Fields is the tags and values to look up.
	Fields []Field `toml:"field"`

	// OID for automatic field population.
	// If provided, init() will populate Fields with all the table columns of the
	// given OID.
	Oid string
	// contains filtered or unexported fields
}

Table holds the configuration for a SNMP table.

func (Table) Build added in v1.14.0

func (t Table) Build(gs snmpConnection, walk bool, tr Translator) (*RTable, error)

Build retrieves all the fields specified in the table and constructs the RTable.

func (*Table) Init added in v1.15.0

func (t *Table) Init(tr Translator) error

Init() builds & initializes the nested fields.

type Translator added in v1.22.0

type Translator interface {
	SnmpTranslate(oid string) (
		mibName string, oidNum string, oidText string,
		conversion string,
		err error,
	)

	SnmpTable(oid string) (
		mibName string, oidNum string, oidText string,
		fields []Field,
		err error,
	)

	SnmpFormatEnum(oid string, value interface{}, full bool) (
		formatted string,
		err error,
	)
}

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