In the last post here, I provided some basic information on SNMP and also shared which networking MIB modules are supported in vSphere 5.1. Before I describe how to use these MIB modules, there is one correction I would like make to the last post. I had mentioned that network related Trap is not supported, but that is not correct. SNMP agent on the host does send SNMP Trap when a physical link goes UP or DOWN. The Trap is like an interrupt. Instead of polling the values of the different network parameters, specific trap tells the user which network parameter needs attention.
Let’s take a look how you can use Networking MIBs to monitor virtual switch parameters.
In this post, I want to discuss one of the important enhancements in vSphere 5.1. It is obviously related to networking and has to do with providing monitoring support to virtual switch parameters through SNMP. We talked about the RSPAN, ERSPAN capabilities and how you can make use of these features to monitor and troubleshoot any networking issue. Similarly, using the new networking MIBs, you will have the visibility into virtual switches. Here are some of the basics on SNMP before I jump-in and discuss the enhancement in detail.
Simple Network Management Protocol (SNMP) is a standard that allows you to manage devices on IP networks. It consists of three key components: Managed devices, Agent, and Network Management System. In a physical network you will find switches, routers and other networking devices as Managed devices with SNMP Agent running on them. The Agent support on these physical network devices allows a centralized Network Management System (NMS) to get information about these devices and also set parameters centrally.
In previous releases of ESXi, only SNMP v1 and v2c was supported on the host. With the latest release of ESXi 5.1, we now have added support for SNMPv3 which provides additional security when collecting data from the ESXi host. You also have the ability to specify where to source hardware alerts using either IPMI sensors (as used by previous release of ESXi) or CIM indicators. You can also filter out specific traps you do not wish to send to your SNMP management server.
In addition to SNMPv3 support, we also now have an ESXCLI equivalent command to the old vicfg-snmp command. This means that you no longer have to use multiple commands to configure your ESXI hosts and can standardize on just using ESXCLI for all your host level configurations.