You can expand a stretched cluster by adding more VxRail nodes to the preferred and non-preferred sites.


You must have a stretched cluster.


  1. Use the VxRail vCenter plug-in to add the additional hosts in availability zone 1 or availability zone 2 to the cluster by performing the VxRail Manager cluster expansion work flow.
    Refer to the Dell EMC VxRail documentation for more details.
  2. Log in to SDDC Manager and run the script to trigger the workflow to import the newly added hosts in the SDDC Manager inventory.
    In the script, provide the root credentials for each host and specify which fault domain the host should be added to.
  3. Using SSH, log in to the SDDC Manager VM with the username vcf and the password you specified in the deployment parameter workbook.
  4. Run the following command to expand the stretched cluster:
    python --workflow expand-stretch-cluster --sc-domain <SDDC-valid-domain-name> --sc-cluster <valid cluster name which is a part of the domain to be stretched> --sc-hosts <valid host names> --witness-host-fqdn <witness host/appliance IP or fqdn> --witness-vsan-ip <witness vsan IP address> --witness-vsan-cidr <witness-vsan-network-IP-address-with-mask> 
    Replace <SDDC-valid-domain-name>, <valid cluster name which is a part of the domain to be stretched>, <valid host names>, <witness vsan IP address>, <witness host/appliance IP or fqdn>, <witness vsan IP address>, and <witness-vsan-network-IP-address-with-mask> with the correct values for your environment.
  5. When prompted, enter the following information:
    • SSO user name and password
    • Root user password for ESXi hosts
    • Fault domain for ESXi hosts
    • vSAN gateway IP for the preferred (primary) and non-preferred (secondary) site
    • vSAN CIDR for the preferred (primary) and non-preferred (secondary) site
    • Confirm the SSH thumbprints for the hosts
  6. Once the workflow is triggered, track the task status in the SDDC Manager UI.
    If the task fails, debug and fix the issue and retry from SDDC Manager UI. Do not run the script again.

What to do next

If you add hosts to a stretched cluster configured for witness traffic separation, perform the following tasks for the added hosts: