Preparing Host transport node in VMware NSX fails with Error code: 100

Products

• VMware NSX Networking

Issue/Introduction

Symptoms:

• The host preparation for NSX-T fails with the below error in NSX UI:

Notification: - The operation creating a transport node from the discovered node failed: General error.
Configure NSX Dialog: - General error (Error code: 100)

• There are no NSX VIBs present on the ESXi host due to the NSX installation not starting, running the below command doesn't return an output:

[root@esxi:~]  esxcli software vib list | grep 'nsx'

• We see the following messages in the NSX-T manager log: /var/log/proton/nsxapi.log 

INFO http-nio-127.0.0.1-7440-exec-28 TransportNodeServiceImpl 89234 FABRIC [nsx@6876 comp="nsx-manager" level="INFO" reqId="65120c2a-4a90-11ee-af84-0050569d8fcf" subcomp="manager" username="admin"] For DVS vSwitch1 found following UplinkKey->UplinkValue {11=Uplink 2, 10=Uplink 1}
INFO http-nio-127.0.0.1-7440-exec-28 TransportNodeServiceImpl 89234 FABRIC [nsx@6876 comp="nsx-manager" level="INFO" reqId="905c6adb-fb16-4055-b79d-1b36fd8592c0" subcomp="manager" username="admin"] Found pnic vmnic0 associated with uplink Uplink 1 on DVS vSwitch1

INFO http-nio-127.0.0.1-7440-exec-21 VcResourceServiceImpl 10780 FABRIC [nsx@6876 comp="nsx-manager" level="INFO" reqId="65120c2a-4a90-11ee-af84-0050569d8fcf" subcomp="manager" username="admin"] VmwareDistributedVirtualSwitch found moref dvs-42
WARN http-nio-127.0.0.1-7440-exec-21 VcResourceServiceImpl 10780 FABRIC [nsx@6876 comp="nsx-manager" level="WARNING" reqId="a36d8701-3664-4ce3-a2a3-fc1b1316327d" subcomp="manager" username="admin"] Unable to fetch DVS switch uuid xx xx xx xx 27 0b 04 d1-53 0f e7 06 94 f5 8f d4
java.lang.NullPointerException: null

Environment

VMware NSX-T Data Center

Cause

You've created a Standard switch with no uplinks assigned to it, and also created a vSphere Distributed Switch (VDS) with the same name (In the example below it's vSwitch1).
Then added the ESXi Host that we need to prepare for NSX to the vDS. 
[root@esxi:~] esxcfg-vswitch -l

Switch Name  Num Ports Used Ports  Configured Ports   MTU    Uplinks
vSwitch1     476        1           128               1500

PortGroup Name    VLAN ID   Used Ports    Uplinks
DSwitch_test      0         0

DVS Name   Num Ports    Used Ports  Configured Ports   MTU     Uplinks
vSwitch1   3476          4          512                1500    vmnic0

DVPort ID                            In use         Client
10                                    1              vmnic0
11                                    0
7                                     1               vmk0 

Resolution

To resolve this issue, please rename the standard switch which has the same name as the vDS used for NSX-T preparation, which will then allow the host to be successfully prepared for NSX.

Workaround:
To workaround this issue, please rename the standard switch which has the same name as the vDS used for NSX-T preparation, which will then allow the host to be successfully prepared for NSX.