Fault tolerance is supported in alpha4. If no other zones show up in the user interface, this usually means that you don't have runners in other availability zones to support fault tolerance, yet.
To enable fault tolerance, you need to:
- Install Elastic Cloud Enterprise on additional hosts to create additional capacity, if you haven't already (remember to specify the first host you installed on with the --coordinator-host parameter).
- Assign roles to the additional hosts. If you already installed ECE on additional hosts, but they aren't showing up as additional zones, you likely just need to give them the allocator role in the UI.
- Resize your cluster on the same page as shown in your screen capture to use additional availability zones.
There's some more documentation around this with links to each of the steps I just described, see https://www.elastic.co/guide/en/cloud-enterprise/current/ece-add-capacity.html#ece-add-capacity.