Heads up! Watch your NIC order when adding more hosts to VCF

VMware Cloud Foundation is a unified SDDC platform for the hybrid cloud. It is based on VMware’s compute, storage, and network virtualization.

VCF can be expanded with more workload domains by adding further hosts, or it can be stretched over two availability zones (AZ). The expansion is initiated by and under control of the SDDC-Manager. The procedure is fairly straightforward and SDDC-Manger does all the configuration tasks in the background, i.e. forming vSAN clusters, networks, kernel ports, vCenters and NSX control planes.

  • setup hosts with ESXi base image
  • confige a management IP address
  • set root credentials
  • configure DNS and NTP
  • import new hosts into SDDC-Manager
  • deploy new WLD

There is a pitfall that can be easily overseen: The order of the new host’s NICs. Before we can import new hosts, we’ll get to see a checklist about the host requirements. The hosts need to have two NICs with at least 10 GBit.

While reading the list there’s a little detail that is often overlooked. Traditional numbering means that both NICs must have numbers vmnic0 and vmnic1. Unfortunately this seems to be hard coded and cannot be changed (as of current version 4.2). To make matters worse, many server systems have onboard 1 GBit network adapters. There’s a KB article that explains how VMware ESXi determines the order in which names are assigned to network devices. It’ll start with onboard NICs and then continues with PCIe cards. As a result you’ll might end up with two 1 GBit onboard NICs as vmnic0 and vmnic1. In this case the bringup of the VCF expansion will fail.

While you can choose NICs during initial VCF bringup, this is not possible during expansion and this time there’s no such thing as a bringup sheet. You can’t select more than two NICs either when using SDDC-Manager. In that case you’ll need to use API-calls.


Currently there’s no other way than to disable onboard NICs in the system BIOS. If your desired NICs still show a higher number you’ll need to put the PCIe card into a lane with lower number.

Reset and re-use VCF 4 Cloud Builder Appliance

As part of a VMware Cloud Foundation (VCF) greenfield deployment, the Cloud Builder appliance is used for one-time use. It automatically deploys the management infrastructure of a VCF cluster and can be discarded afterwards.

The ideal situation is that the previously created workbook or JSON is processed and the cluster is successfully created.

In the UI of the Cloud Builder, however, there is no option to reset the wizard and restart it from zero. For example, when requirements have changed and a new or adapted workbook is to be used. Or you want to use the appliance for another rollout. In this case, the appliance would have to be completely redeployed. Any errors in the JSON file cannot be corrected this way either.

However, there is a trick to reset the Cloud Builder to zero and feed it with a modified JSON file. This is thanks to an API call that may have been ‘forgotten’ during development. In order to do so, we have to log in to the console of the Cloud Builder as user root.

[Optional] It may be easier to grant the root user temporary SSH access. Log in to the VM console as root and edit the sshd configuration.

sudo vi /etc/ssh/sshd_config

Browse the sshd_config and look for the line PermitRootLogin no. Disable the line by putting a # in front of it.

# PermitRootLogin no

Save the configuration and open a SSH session as user root. We now can execute an API call as user root.

curl -X GET http://localhost:9080/bringup-app/bringup/sddcs/test/deleteAll

Login to the web UI of the Cloud Builder appliance. You now can start from the beginning.


VMware Cloud Platform Tech Zone – Re-use Cloud Builder for Another Deployment