Upgrading ESXi 5.0 to 6.0 U1? Watch out for SNMP

Recently, I upgraded a couple of VMware vSphere ESXi 5.0 servers all the way up to ESXi 6.0 U1 (quite the jump). The process itself is pretty smooth as long as you make sure all your environment compatibility levels check out.
If the ESXi servers are joined to an AD domain via Authentication Services, I’d recommend removing it and setting it back to Local Authentication before starting the upgrade. This can potentially help you avoid an issue where the ESXi server hangs in the upgrade process as it starts to look for the domain (you can always add it back later).
Another caveat that can easily slip by without warning, and the main reason for this post, is the status of the SNMP Server service. It may not start even though it is set to start up with the host. A quick look at the firewall properties will show the service stopped, and if you try to start it you’ll receive “An error occurred during host configuration” popup error:

Call “HostServiceSystem.Start” for object “serviceSystem-1974” on vCenter Server “<server_name>” failed.

The reason for this is that the snmp.xml file in the host gets corrupted during the v5.0 to v6 upgrade process.
To correct this issue I applied VMware KB2056832

1. SSH to ESXi server.
2. Navigate to:

cd /etc/vmware

3. Make a backup copy of snmp.xml:

cp snmp.xml snmp.xml.backup

4. Edit the snmp.xml file:

vi snmp.xml
Press i key for insert mode

5. Delete the corrupted configuration.
6. Copy & paste the following into the snmp.xml file:

<?xml version=”1.0″ encoding=”ISO-8859-1″?>
<config>
<snmpSettings>
<enable>true</enable>
<port>161</port>
<syscontact></syscontact>
<syslocation></syslocation>
<EnvEventSource>indications</EnvEventSource>
<communities>public</communities>
<loglevel>info</loglevel>
<authProtocol></authProtocol>
<privProtocol></privProtocol>
</snmpSettings>
</config>
 

7. Save & close file:

Type <Esc> key then :wq
Press <Enter>

8. Restart snmp service:

/etc/init.d/snmpd restart
 
You should now have a working SNMP service!
About Anexinet
Anexinet is a leading professional consulting and services company, providing a broad range of services and solutions around digital disruption, analytics (and big data), and hybrid and private cloud strategies. Anexinet brings insight into how technology will impact how business decisions will be made and how our clients interact with their customers in the future.
Josue Molina, jmolina@anexinet.com