Any update on your situation?
Resolution: Not fixable
I created a SolarWinds ticket for this and got some responses but all of the steps were basic items I already tried and they ended up not being able to help me. I gave up on trying to troubleshoot the issue and also closed the support ticket with SolarWinds.
The two ESXi 5.0 Hosts are still showing their heath status as undefined and are unable to be polled for hardware health. All other VMware polling using SNMP and the VMware API work and I see all the VM information.
What I cant see (or get alerts on) without the CIM polling working in SolarWinds is if there is a hardware issue on the ESXi Host such as with the RAID controller or one of the drives.
I did a bunch of tests myself and discovered a few new tools I had not used before for troubleshooting - slptools and CIM polling with Powershell.
1. I get the same 501 HTTP error from all Hosts (5.0 and 5.5) when I attempt to go to https://host_IP_address:5989 . I think this error is not the true reason for the issue.
2. I can query the SLP service on the network where the Hosts are and see that both 5.0 and 5.5 ESXi Hosts are listening for wbem (CIM service) and respond to queries.
C:\Program Files\OpenSLP>slptool findsrvtypes
3. I can query the CIM attributes on the 5.0 Hosts and the CIM service responds
C:\Program Files\OpenSLP>slptool findattrs service:wbem:https://esxi_host_IP:5989
(template-type=wbem),(template-version=1.0),(template-description=This template describes the attributes used for advertising WBEM Servers.),(template-url-syntax=https://esxi_host_ip:5989),(service-hi-name=sfcb),(service-hi-description=Small Footprint CIM Broker 1.3.7),(service-id=76a5b1be-f9cd-4b98-8764-771b98ff382a),(CommunicationMechanism=CIM-XML),(InteropSchemaNamespace=root/interop),(ProtocolVersion=1.0),(FunctionalProfilesSupported=Basic Read,Basic Write,Instance Manipulation,Association Traversal,Query Execution,Indications),(MultipleOperationsSupported=false),(AuthenticationMechanismsSupported=Basic),(Namespace=root/interop,root/cimv2,vmware/esxv2,root/config),(Classinfo=0,0,0,0),(RegisteredProfilesSupported=SNIA:Job Control,DMTF:Software Update,DMTF:PCI Device,DMTF:Software Inventory,DMTF:Indications,Other:IPMI OEM Extension,DMTF:Sensors,DMTF:Profile Registration,DMTF:System Memory,DMTF:Record Log,DMTF:CPU,DMTF:Fan,DMTF:Base Server,DMTF:Battery,DMTF:Physical Asset,DMTF:Power Supply,DMTF:Power State Management)
4. The 5.0 Hosts will not poll using the SolarWinds.HardwareHealthTool.exe tool. It shows the same 501 error that the NPM web console shows in the hardware health panel.
5. I can poll the 5.0 Hosts using powershell though
$ipaddress = "172.31.xxx.xxx"
$HostUsername = "root"
$CIOpt = New-CimSessionOption -SkipCACheck -SkipCNCheck -SkipRevocationCheck -Encoding Utf8 -UseSsl
$Session = New-CimSession -Authentication Basic -Credential $HostUsername -ComputerName $Ipaddress -port 443 -SessionOption $CIOpt
Get-CimInstance -CimSession $Session -ClassName CIM_Chassis
Caption : Chassis
ChassisPackageType : 23
ChassisTypeDescription : Rack Mount Chassis
CreationClassName : OMC_Chassis
Manufacturer : Dell Inc.
Model : PowerEdge R510
PSComputerName : 172.31.xxx.xxx
5. Hardware health appears correctly when connecting to the ESXi Hosts using the vSphere client, and when connecting to the vmk using a web browser at https://esxi_host_ip/mob and navigating through the Managed Object Browser web data.
6. I have removed the hosts from NPM and then added them back, changed the polling between a) ICMP only with VMware polling, b) SNMP polling with VMware polling c) SNMP polling without VMware polling, restarted the management interfaces on the ESXi Hosts, and verify that all services are running correctly and that there are no firewall issues.