Test all VLANs presented to UCS

[JDMils]

Our existing UCS domain (Fabric1) is now full and we have commissioned a new UCS domain (Fabric2- new FIs & chassis) and have plans to add VMware hosts from Fabric2 to a shared vCenter cluster which currently has all hosts from Fabric1.

This should be fine.

However, there are 418 VLANs in the shared cluster and although we "think" we have correctly provisioned the same 418 VLANs to Fabric2, we cannot be sure unless we test each one. The problem is that is a customer virtual migrates from a host in Fabric1 to a host in Fabric2, we don't want to have a P1 outage to the virtual because the respective VLAN was either not provisioned or not correctly provisioned.

I would like to ask if there is a function in UCSM where we can test each VLAN's connectivity before bringing the domain into production?

[Kirk J]

You can issue some basic NXOS level commands such as 'show vlan' to confirm that the vlans are globally defined on each FI.

"Testing" vlan communication success is going to involve a lot more than just UCSM config, and would require testing at the ESXi layer as well to confirm vlans/.port groups are actually applying the correct vlan tag.

Standard places to check for vlan connectivity:

• Globally defined in UCSM
• Service profiles/NVICs
• Portgroup tagging( at OS/Hypervisor layer)

Kirk...

[JDMils]

Thanks Kirk. Will this verify the VLAN has connectivity? For example, if we define the VLANs in UCSM, they will of course exist in UCSM, however I would also like to verify that the VLAN has connectivity to the uplink switch as well. This is to ensure the uplink switch has trunked all the VLANs correctly to the FIs.

The only way to really test the connectivity is to have a virtual on the ESXi host, connect it to each VLAN, one-by-one, provide it with the IP details for each VLAN, and issue a PING to the gateway which if tested OK, indicates the ESXi port group has connectivity to the VLAN and thus to the "outside world". However for 400+ VLANs, this would be a nightmare to test manually.

[Kirk J]

You could put some sort of script together in ESXi that updated a VMK interface's IP info, and vlan.

The underlying VMNICs (vnic in service profile) would need to allow/trunk all the vlans in question.

esxcli network ip interface ipv4 set -i vmk1 -I ip address -N subnet -t static

esxcfg-vswitch -v VLANID -p portgroup vSwitch

vmkping  -I vmk1 x.x.x.x

It might be easier to use the vmware powertools/powershell modules, to connect to a specific ESXi host, and feed the corelating IP and VLAN from a CSV file.  See https://communities.vmware.com/t5/VMware-PowerCLI-Discussions/script-to-change-vlanid-ip-and-gateway-for-ESXi/td-p/2289007 for some discussions about using powershell for similar use.

Kirk...