Monitoring: SNMP Support

Simple Network Management Protocol (SNMP) is an Internet-standard protocol for collecting and organizing information about managed devices on IP networks. It is used primarily for monitoring network services. SNMP exposes management data in the form of variables (metrics) which describe the system status and configuration. These metrics can then be remotely queried (and, in some circumstances, manipulated) by managing applications.

In RavenDB we have support for SNMP which allows monitoring tools like Zabbix, PRTG and Datadog direct access to the internal details of RavenDB. We expose a long list of metrics: CPU and memory usage, server total requests, the loaded databases, and also database specific metrics like the number of indexed items per second, document writes per second, storage space each database takes, and so on.

You can still monitor what is going on with RavenDB directly from the Studio, or by using one of our monitoring tools. However, using SNMP might be easier in some cases. As users start running large numbers of RavenDB instances, it becomes impractical to deal with each of them individually, and using a monitoring system that can watch many servers becomes advisable.

RavenDB is already configured to support SNMP. All you have to do is enable it and restart the server. This is done by adding the following key to your settings.json file:

{
    ...
    "Monitoring.Snmp.Enabled": true
    ...
}

Configuration options

There are several configurable SNMP properties in RavenDB.

For SNMPv1:

• The SNMP port - default: 161
• List of supported SNMP versions - default: "V2C;V3"

For SNMPv2c:

• The community string - default: "ravendb"

The community string is used like a password. It is sent with each SNMP GET request and allows or denies access to the monitored device.

For SNMPv3:

• Authentication protocol - default: "SHA1"
• The user for authentication - default: "ravendb"
• The authentication password - default: null; if set to null the community string is used instead.
• Privacy protocol - default: None
• Privacy password - default: "ravendb"

You can change these properties with the following configuration keys:

{
    ...
    "Monitoring.Snmp.Port": 12345,  
    "Monitoring.Snmp.SupportedVersions": "V#",  
    "Monitoring.Snmp.Community": "yourString",  
    "Monitoring.Snmp.AuthenticationProtocol": "protocol",  
    "Monitoring.Snmp.AuthenticationUser": "yourUser",  
    "Monitoring.Snmp.AuthenticationPassword": "yourString",  
    "Monitoring.Snmp.PrivacyProtocol": "protocol",  
    "Monitoring.Snmp.PrivacyPassword": "yourString"  
    ...
}

It is usually easy to query the exposed metrics using a monitoring tool. (Example). However, you should also be able to access those directly using any SNMP agent like Net-SNMP. Each metric has a unique identifier (OID) and can be accessed individually.

The most basic SNMP commands are snmpget, snmpset and snmptrapd.
For example, using the SNMP agent you could run the following snmpget commands which get the server up-time metric.

For SNMPv2c:

snmpget -v 2c -c ravendb live-test.ravendb.net 1.3.6.1.4.1.45751.1.1.1.3

Where ravendb is the community string (configured via Monitoring.Snmp.Community configuration option) and "live-test.ravendb.net" is the host.

For SNMPv3

snmpget -v 3 -l authNoPriv -u ravendb -a SHA -A ravendb live-test.ravendb.net 1.3.6.1.4.1.45751.1.1.1.3

-l authNoPriv sets the security level to use authentication but no privacy. -u ravendb sets the user for authentication purposes to "ravendb", -a SHA sets the authentication protocol to SHA, and -A ravendb sets the authentication password to "ravendb".

Example request for server URL, and the response:

ml054@MARCIN-WIN:~$ snmpget -v 2c -c ravendb live-test.ravendb.net 1.3.6.1.4.1.45751.1.1.1.1.1
iso.3.6.1.4.1.45751.1.1.1.1.1 = STRING: "http://bf7631445baf:8080"

curl -X GET http://live-test.ravendb.net/monitoring/snmp?oid=1.3.6.1.4.1.45751.1.1.1.3

{"Value":"4.21:32:56.0700000"}

List of OIDs

Templates

For easier setup we have prepared a few templates for monitoring tools which can be found here.
These templates include the metrics and their associated OIDs.