SNMP device monitoring with Netdata

Collects data from any SNMP device and uses the gosnmp package.

It supports:

• all SNMP versions: SNMPv1, SNMPv2c and SNMPv3.
• any number of SNMP devices.
• each SNMP device can be used to collect data for any number of charts.
• each chart may have any number of dimensions.
• each SNMP device may have a different update frequency.
• each SNMP device will accept one or more batches to report values (you can set max_request_size per SNMP server, to control the size of batches).

Configuration

Edit the go.d/snmp.conf configuration file using edit-config from the Netdata config directory, which is typically at /etc/netdata.

cd /etc/netdata # Replace this path with your Netdata config directory
sudo ./edit-config go.d/snmp.conf

The configuration file is a list of data collection jobs. Jobs allow you to collect values from multiple sources, each source will have its own set of charts.

Generally the format is:

jobs:
  - name: name1
    ...  # other configuration parameters
  - name: name2
    ...  # other configuration parameters
  - name: name3
    ...  # other configuration parameters

Job configuration parameters

Parameter	Default value	Description
name	-	the data collection job name
update_every	10	the update frequency for each target, in seconds
hostname	127.0.0.1	the target ipv4 address
community	public	SNMPv1/2 community string
options.version	2	SNMP version
options.port	161	the target port
options.retries	1	the number of retries to attempt
options.timeout	10	the timeout for one SNMP request/response
options.max_request_size	60	the maximum number of oids allowed in one one SNMP request
user.name	-	the SNMPv3 user name
user.level	-	the security level of SNMPv3 messages
user.auth_proto	-	the authentication protocol for SNMPv3 messages
user.auth_key	-	the authentication protocol pass phrase
user.priv_proto	-	the privacy protocol for SNMPv3 messages
user.priv_key	-	the privacy protocol pass phrase
charts	[]	the list of charts
charts.id	-	is used to uniquely identify the chart
charts.title	Untilted chart	the text above the chart
charts.units	num	the label of the vertical axis of the chart
charts.family	charts.id	the name of the dashboard submenu under which each chart will be displayed
charts.type	line	the chart type (one of line, area or stacked)
charts.priority	70000	the priority of the chart as rendered on the web page
charts.multiply_range	[]	is used when you need to define many charts using incremental OIDs
charts.dimensions	[]	the list of chart dimensions
charts.dimensions.oid	-	the OID path to the metric you want to collect
charts.dimensions.name	-	the name of the dimension as it will appear at the legend of the chart
charts.dimensions.algorithm	absolute	the dimension algorithm (one of absolute, incremental)
charts.dimensions.multiplier	1	the value to multiply the collected value, applied to convert it properly to units
charts.dimensions.divisor	1	the value to divide the collected value, applied to convert it properly to units

Example: Using SNMPv1/2

In this example:

• the SNMP device is 192.0.2.1.
• the SNMP version is 2.
• the SNMP community is public.
• we will update the values every 10 seconds.
• we define 2 charts bandwidth_port1 and bandwidth_port2, each having 2 dimensions: in and out.

SNMPv1: just set options.version to 1.

jobs:
  - name: switch
    update_every: 10
    hostname: "192.0.2.1"
    community: public
    options:
      version: 2
    charts:
      - id: "bandwidth_port1"
        title: "Switch Bandwidth for port 1"
        units: "kilobits/s"
        type: "area"
        family: "ports"
        dimensions:
          - name: "in"
            oid: "1.3.6.1.2.1.2.2.1.10.1"
            algorithm: "incremental"
            multiplier: 8
            divisor: 1000
          - name: "out"
            oid: "1.3.6.1.2.1.2.2.1.16.1"
            multiplier: -8
            divisor: 1000
      - id: "bandwidth_port2"
        title: "Switch Bandwidth for port 2"
        units: "kilobits/s"
        type: "area"
        family: "ports"
        dimensions:
          - name: "in"
            oid: "1.3.6.1.2.1.2.2.1.10.2"
            algorithm: "incremental"
            multiplier: 8
            divisor: 1000
          - name: "out"
            oid: "1.3.6.1.2.1.2.2.1.16.2"
            multiplier: -8
            divisor: 1000

Example: Using SNMPv3

To use SNMPv3:

• use user instead of community.
• set options.version to 3.

The rest of the configuration is the same as in the SNMPv1/2 example.

jobs:
  - name: switch
    update_every: 10
    hostname: "192.0.2.1"
    options:
      version: 3
    user:
      name: "username"
      level: "authPriv"
      auth_proto: "sha256"
      auth_key: "auth_protocol_passphrase"
      priv_proto: "aes256"
      priv_key: "priv_protocol_passphrase"

SNMPv3 message authentication and privacy configuration options

The security of an SNMPv3 message as per RFC 3414 (user.level):

String value	Int value	Description
none	1	no message authentication or encryption
authNoPriv	2	message authentication and no encryption
authPriv	3	message authentication and encryption

The digest algorithm for SNMPv3 messages that require authentication (user.auth_proto):

String value	Int value	Description
none	1	no message authentication
md5	2	MD5 message authentication (HMAC-MD5-96)
sha	3	SHA message authentication (HMAC-SHA-96)
sha224	4	SHA message authentication (HMAC-SHA-224)
sha256	5	SHA message authentication (HMAC-SHA-256)
sha384	6	SHA message authentication (HMAC-SHA-384)
sha512	7	SHA message authentication (HMAC-SHA-512)

The encryption algorithm for SNMPv3 messages that require privacy (user.priv_proto):

String value	Int value	Description
none	1	no message encryption
des	2	ES encryption (CBC-DES)
aes	3	128-bit AES encryption (CFB-AES-128)
aes192	4	192-bit AES encryption (CFB-AES-192) with "Blumenthal" key localization
aes256	5	256-bit AES encryption (CFB-AES-256) with "Blumenthal" key localization
aes192c	6	192-bit AES encryption (CFB-AES-192) with "Reeder" key localization
aes256c	7	256-bit AES encryption (CFB-AES-256) with "Reeder" key localization

Example: Using charts.multiply_range option

If you need to define many charts using incremental OIDs, you can use the charts.multiply_range option.

This is like the SNMPv1/2 example, but the option will multiply the current chart from 1 to 24 inclusive, producing 24 charts in total for the 24 ports of the switch 192.0.2.1.

Each of the 24 new charts will have its id (1-24) appended at:

• its chart unique id, i.e. bandwidth_port_1 to bandwidth_port_24.
• its title, i.e. Switch Bandwidth for port 1 to Switch Bandwidth for port 24.
• its oid (for all dimensions), i.e. dimension in will be 1.3.6.1.2.1.2.2.1.10.1 to 1.3.6.1.2.1.2.2.1.10.24.
• its priority will be incremented for each chart so that the charts will appear on the dashboard in this order.

jobs:
  - name: switch
    update_every: 10
    hostname: "192.0.2.1"
    community: public
    options:
      version: 2
    charts:
      - id: "bandwidth_port"
        title: "Switch Bandwidth for port"
        units: "kilobits/s"
        type: "area"
        family: "ports"
        multiply_range: [1, 24]
        dimensions:
          - name: "in"
            oid: "1.3.6.1.2.1.2.2.1.10"
            algorithm: "incremental"
            multiplier: 8
            divisor: 1000
          - name: "out"
            oid: "1.3.6.1.2.1.2.2.1.16"
            multiplier: -8
            divisor: 1000

Data collection speed

Keep in mind that many SNMP switches and routers are very slow. They may not be able to report values per second. go.d.plugin reports the time it took for the SNMP device to respond when executed in the debug mode.

Also, if many SNMP clients are used on the same SNMP device at the same time, values may be skipped. This is a problem of the SNMP device, not this collector. In this case, consider reducing the frequency of data collection ( increasing update_every).

Finding OIDs

Use snmpwalk, like this:

snmpwalk -t 20 -O fn -v 2c -c public 192.0.2.1

• -t 20 is the timeout in seconds.
• -O fn will display full OIDs in numeric format.
• -v 2c is the SNMP version.
• -c public is the SNMP community.
• 192.0.2.1 is the SNMP device.

Troubleshooting

To troubleshoot issues with the snmp collector, run the go.d.plugin with the debug option enabled. The output should give you clues as to why the collector isn't working.

First, navigate to your plugins directory, usually at /usr/libexec/netdata/plugins.d/. If that's not the case on your system, open netdata.conf and look for the setting plugins directory. Once you're in the plugin's directory, switch to the netdata user.

cd /usr/libexec/netdata/plugins.d/
sudo -u netdata -s

You can now run the go.d.plugin to debug the collector:

./go.d.plugin -d -m snmp