Nutanix Flow is a security feature which allows for firewall-type protection at the VM layer. However, flow goes another step further in allowing the configuration of “Security Policies” which can govern individual VMs or “Categories” of VMs or (grouped into convenient application-specific domains).
Flow is a function of Prism Central and is disabled by default. To enable it, simply access the “Microsegmentation” option from within the “Prism Central Settings” options, tick the “Enable Microsegmentation” check box and click “OK”. To note, you may first want to review the capability checks that Prism Central automatically performs on all registered clusters prior to enablement, which is also possible right from within the “Enable Microsegmentation” dialog box.
You can find more information regarding Nutanix Flow as per the FLOW MICROSEGMENTATION GUIDE found on the Nutanix Support Portal.