17 April 2012 Karim Elatov

I wanted to get more host information from an ESX host when querying the host with snmp. Specifically, I was interested in the Host_Resources MIB (Configuring the Net-SNMP Agent on ESX Hosts” article, I ran the following to enable snmpd:

# service snmpd start
Starting snmpd: [ OK ]

Now querying for host resources, I only see a limited output:

# snmpwalk -v 2c -c public localhost 1.3.6.1.2.1.25
HOST-RESOURCES-MIB::hrSystemUptime.0 = Timeticks: (2568848477) 297 days, 7:41:24.77
HOST-RESOURCES-MIB::hrSystemUptime.0 = No more variables left in this MIB View (It is past the end of the MIB tree)

This is actually expected since net-snmp on ESX is not supported as per KB 1020649. However there is supposed to be a lot more output, checking out the setting for the snmpd service I see the following:

# grep 1.3.6.1.2.1.25 /etc/snmp/snmpd.conf
view systemview included .1.3.6.1.2.1.25.1.1

That MIB is limited, the root OID of the Host-Resources MIB is .1.3.6.1.2.1.25, but we are limiting the OID to be a subset of the OID (.1.3.6.1.2.1.25.1.1). More information regarding how OIDs work can be found here. So let’s go ahead and allow the whole MIB to be queried. Edit the file with vi:

# vi /etc/snmp/snmpd.conf

Scroll down to the line that looks like this:

view systemview included .1.3.6.1.2.1.25.1.1

and make it look like this:

view systemview included .1.3.6.1.2.1.25

After you make the change, exit vi (by typing “:wq”) and confirm the file was edited properly:

# grep 1.3.6.1.2.1.25 /etc/snmp/snmpd.conf
view systemview included .1.3.6.1.2.1.25

If you see the same output as above then restart the snmpd service to apply the changes:

# service snmpd restart
Stopping snmpd: [ OK ]
Starting snmpd: [ OK ]

And if you run the same query again:

# snmpwalk -v 2c -c public localhost 1.3.6.1.2.1.25
HOST-RESOURCES-MIB::hrSystemUptime.0 = Timeticks: (2568874428) 297 days, 7:45:44
.28
HOST-RESOURCES-MIB::hrSystemDate.0 = STRING: 2012-4-14,22:9:35.0,-7:0
HOST-RESOURCES-MIB::hrSystemInitialLoadDevice.0 = INTEGER: 1536
HOST-RESOURCES-MIB::hrSystemInitialLoadParameters.0 = STRING: "ro root=UUID=5ac0
8fa5-b922-441c-80e1-d22018de2419 mem=800M nousbstorage quiet
"
HOST-RESOURCES-MIB::hrSystemNumUsers.0 = Gauge32: 2
HOST-RESOURCES-MIB::hrSystemProcesses.0 = Gauge32: 103
HOST-RESOURCES-MIB::hrSystemMaxProcesses.0 = INTEGER: 0
HOST-RESOURCES-MIB::hrMemorySize.0 = INTEGER: 802360 KBytes
HOST-RESOURCES-MIB::hrStorageIndex.1 = INTEGER: 1
...
...

The output was much larger. This only works for ESX and not for ESXi and as the “2005377, the Host-Resources MIB is added for ESXi 5.0, so if you want to get that information on an ESXi host, then update to 5.0 :)


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