snmp_notifier

SNMP Notifier

snmp_notifier receives alerts from the Prometheus' Alertmanager and routes them as SNMP traps.

Overview

The SNMP notifier receives alerts and sends them as SNMP traps to any given SNMP poller.

It has been created to handle older monitoring and alerting systems such as Nagios or Centreon.

Prometheus' Alertmanager sends the alerts to the SNMP notifier on its HTTP API. The SNMP notifier then looks for OID in the given alerts' labels. Each trap is sent with a unique ID, which allows, if the alert is updated or once it is resolved, to send additional traps with updated status and data.

Install

There are various ways to install the SNMP notifier:

Helm Chart

The SNMP notifier chart is available via the Prometheus Community Kubernetes Helm Charts:

helm repo add prometheus-community https://prometheus-community.github.io/helm-charts
helm install snmp-notifier prometheus-community/alertmanager-snmp-notifier --set 'snmpNotifier.snmpDestinations={my-snmp-server:162}'

Refer to the chart values to see the available options.

Docker Images

Docker images are available on the Docker Hub.

Precompiled binaries

Precompiled binaries are available in the release section of this repository.

Compiling the binary

Check out the source code and build it manually:

git clone https://github.com/maxwo/snmp_notifier.git
cd snmp_notifier
make build
./snmp_notifier

Running and configuration

Prometheus' alerts configuration

OID may be added to the alert labels to identify the kind of trap to be sent:

A default OID is specified in the SNMP notifier if none is found in the alert. This can be useful if you want all the alerts to share the same OID.

groups:
  - name: service
    rules:
      - alert: ServiceIsDown
        expr: up == 0
        for: 5m
        labels:
          severity: "critical"
          type: "service"
          oid: "1.3.6.1.4.1.123.0.10.1.1.1.5.1"
          environment: "production"
        annotations:
          description: "Service {{ $labels.job }} on {{ $labels.instance }} is down"
          summary: "A service is down."

Alertmanager configuration

The Alertmanager should be configured with the SNMP notifier as alert receiver:

receivers:
  - name: "snmp_notifier"
    webhook_configs:
      - send_resolved: true
        url: http://snmp.notifier.service:9464/alerts

Note that the send_resolved option allows the notifier to update the trap status to normal.

SNMP notifier configuration

Launch the snmp_notifier executable with the help flag to see the available options.

$ ./snmp_notifier --help
usage: snmp_notifier [<flags>]

A tool to relay Prometheus alerts as SNMP traps


Flags:
  -h, --[no-]help                Show context-sensitive help (also try --help-long and --help-man).
      --web.listen-address=:9464 ...
                                 Addresses on which to expose metrics and web interface. Repeatable for multiple addresses.
      --web.config.file=""       [EXPERIMENTAL] Path to configuration file that can enable TLS or authentication. See:
                                 https://github.com/prometheus/exporter-toolkit/blob/master/docs/web-configuration.md
      --alert.severity-label="severity"
                                 Label where to find the alert severity.
      --alert.severities="critical,warning,info"
                                 The ordered list of alert severities, from more priority to less priority.
      --alert.default-severity="critical"
                                 The alert severity if none is provided via labels.
      --snmp.version=V2c         SNMP version. V2c and V3 are currently supported.
      --snmp.destination=127.0.0.1:162 ...
                                 SNMP trap server destination.
      --snmp.retries=1           SNMP number of retries
      --snmp.trap-oid-label="oid"
                                 Label where to find the trap OID.
      --snmp.trap-default-oid="1.3.6.1.4.1.98789"
                                 Trap OID to send if none is found in the alert labels.
      --snmp.trap-description-template=description-template.tpl
                                 SNMP description template.
      --snmp.extra-field-template=4=extra-field-template.tpl ...
                                 SNMP extra field templates, eg. --snmp.extra-field-templates=4=new-field.template.tpl to add a 4th
                                 field to the trap, with the given template file. You may add several fields using that flag several
                                 times.
      --snmp.timeout=5s          SNMP timeout duration
      --snmp.community="public"  SNMP community (V2c only). Passing secrets to the command line is not recommended, consider using the
                                 SNMP_NOTIFIER_COMMUNITY environment variable instead. ($SNMP_NOTIFIER_COMMUNITY)
      --[no-]snmp.authentication-enabled
                                 Enable SNMP authentication (V3 only).
      --snmp.authentication-protocol=MD5
                                 Protocol for password encryption (V3 only). MD5 and SHA are currently supported.
      --snmp.authentication-username=USERNAME
                                 SNMP authentication username (V3 only). Passing secrets to the command line is not
                                 recommended, consider using the SNMP_NOTIFIER_AUTH_USERNAME environment variable instead.
                                 ($SNMP_NOTIFIER_AUTH_USERNAME)
      --snmp.authentication-password=PASSWORD
                                 SNMP authentication password (V3 only). Passing secrets to the command line is not
                                 recommended, consider using the SNMP_NOTIFIER_AUTH_PASSWORD environment variable instead.
                                 ($SNMP_NOTIFIER_AUTH_PASSWORD)
      --[no-]snmp.private-enabled
                                 Enable SNMP encryption (V3 only).
      --snmp.private-protocol=DES
                                 Protocol for SNMP data transmission (V3 only). DES and AES are currently supported.
      --snmp.private-password=SECRET
                                 SNMP private password (V3 only). Passing secrets to the command line is not recommended, consider using
                                 the SNMP_NOTIFIER_PRIV_PASSWORD environment variable instead. ($SNMP_NOTIFIER_PRIV_PASSWORD)
      --snmp.security-engine-id=SECURITY_ENGINE_ID
                                 SNMP security engine ID (V3 only).
      --snmp.context-engine-id=CONTEXT_ENGINE_ID
                                 SNMP context engine ID (V3 only).
      --snmp.context-name=CONTEXT_ENGINE_NAME
                                 SNMP context name (V3 only).
      --log.level=info           Only log messages with the given severity or above. One of: [debug, info, warn, error]
      --log.format=logfmt        Output format of log messages. One of: [logfmt, json]
      --[no-]version             Show application version.

Also, it is recommended to use the following environment variables to set the SNMP secrets:

Any Go template directive may be used in the snmp.trap-description-template file.

Examples

Simple Usage

Here are 2 example traps received with the default configuration. It includes 2 firing alerts sharing the same OID, and 1 resolved alert.

Traps include 3 fields:

• a trap unique ID;
• the alert/trap status;
• a description of the alerts.

$ snmptrapd -m ALL -m +SNMP-NOTIFIER-MIB -f -Of -Lo -c scripts/snmptrapd.conf
 Agent Address: 0.0.0.0
 Agent Hostname: localhost
 Date: 1 - 0 - 0 - 1 - 1 - 1970
 Enterprise OID: .
 Trap Type: Cold Start
 Trap Sub-Type: 0
 Community/Infosec Context: TRAP2, SNMP v2c, community public
 Uptime: 0
 Description: Cold Start
 PDU Attribute/Value Pair Array:
.iso.org.dod.internet.mgmt.mib-2.system.sysUpTime.sysUpTimeInstance = Timeticks: (853395100) 98 days, 18:32:31.00
.iso.org.dod.internet.snmpV2.snmpModules.snmpMIB.snmpMIBObjects.snmpTrap.snmpTrapOID.0 = OID: .iso.org.dod.internet.private.enterprises.snmpNotifier.snmpNotifierDefaultTrap
.iso.org.dod.internet.private.enterprises.snmpNotifier.snmpNotifierAlertsObjects.snmpNotifierAlertId = STRING: "1.3.6.1.4.1.98789[environment=production,label=test]"
.iso.org.dod.internet.private.enterprises.snmpNotifier.snmpNotifierAlertsObjects.snmpNotifierAlertSeverity = STRING: "critical"
.iso.org.dod.internet.private.enterprises.snmpNotifier.snmpNotifierAlertsObjects.snmpNotifierAlertDescription = STRING: "2/3 alerts are firing:

Status: critical
- Alert: TestAlert
  Summary: this is the summary
  Description: this is the description on job1

Status: warning
- Alert: TestAlert
  Summary: this is the random summary
  Description: this is the description of alert 1"
 --------------

With extra fields

You may add additional fields thanks to the --snmp.extra-field-template arguments.

For instance, the template {{ len .Alerts }} alerts are firing. given in the --snmp.extra-field-template=4=alert-count.tpl argument will produce:

$ snmptrapd -m ALL -m +SNMP-NOTIFIER-MIB -f -Of -Lo -c scripts/snmptrapd.conf
 Agent Address: 0.0.0.0
 Agent Hostname: localhost
 Date: 1 - 0 - 0 - 1 - 1 - 1970
 Enterprise OID: .
 Trap Type: Cold Start
 Trap Sub-Type: 0
 Community/Infosec Context: TRAP2, SNMP v2c, community public
 Uptime: 0
 Description: Cold Start
 PDU Attribute/Value Pair Array:
.iso.org.dod.internet.mgmt.mib-2.system.sysUpTime.sysUpTimeInstance = Timeticks: (2665700) 7:24:17.00
.iso.org.dod.internet.snmpV2.snmpModules.snmpMIB.snmpMIBObjects.snmpTrap.snmpTrapOID.0 = OID: .iso.org.dod.internet.private.enterprises.snmpNotifier.snmpNotifierDefaultTrap
.iso.org.dod.internet.private.enterprises.snmpNotifier.snmpNotifierAlertsObjects.snmpNotifierAlertId = STRING: "1.3.6.1.4.1.98789[environment=production,label=test]"
.iso.org.dod.internet.private.enterprises.snmpNotifier.snmpNotifierAlertsObjects.snmpNotifierAlertSeverity = STRING: "critical"
.iso.org.dod.internet.private.enterprises.snmpNotifier.snmpNotifierAlertsObjects.snmpNotifierAlertDescription = STRING: "2/3 alerts are firing:

Status: critical
- Alert: TestAlert
  Summary: this is the summary
  Description: this is the description on job1

Status: warning
- Alert: TestAlert
  Summary: this is the random summary
  Description: this is the description of alert 1"
.iso.org.dod.internet.private.enterprises.snmpNotifier.snmpNotifierAlertsObjects.4 = STRING: "2 alerts are firing."
--------------

Contributing

Issues, feedback, PR welcome.