To enable fault tolerance (FT) in a vSphere cluster, follow these steps:
1. Ensure that the vSphere hosts in the cluster meet the requirements for FT, including having processors that support FT and having shared storage.
1. Create a new virtual machine (VM) or select an existing VM to enable FT for.
1. Right-click the selected VM and choose Fault Tolerance > Turn On Fault Tolerance.
1. On the Configure Fault Tolerance wizard, choose the secondary host for the FT VM.
1. Select storage for the VM and click Next.
1. Configure FT networking and choose the appropriate options in the wizard.
1. Review the configuration and click Finish to complete the configuration.
1. The primary VM and the secondary VM will be created, and the FT configuration will be enabled.
1. Monitor the FT VM to ensure it stays synchronized and to troubleshoot any issues that may arise.
1. Once FT is enabled, ensure that the vSphere cluster is configured for admission control to ensure that there is always sufficient capacity and resources to accommodate the FT VMs.
