is there a way for now to test cluster ve 4.x and ha with 2 nodes like "Two-Node High Availability Cluster" for proxmox 3.x ?
If you want reliable HA - and if you need HA you always want reliability - you need at least 3 nodes. This is true for a 2.x, 3.x and also for a 4.x HA cluster.
A two node setup is NEVER optimal and not recommended. If you have just two boxes, just run a cluster without HA.
 
	 
	 
 
		 
 
		 
 
		 ? If the user is in front of the failing node and is told to unplug it's power and start VMs through web interface (no, 99% users can't ssh into the box and run a script or cp for vm config) it's a fair situation, isn't it?
 ? If the user is in front of the failing node and is told to unplug it's power and start VMs through web interface (no, 99% users can't ssh into the box and run a script or cp for vm config) it's a fair situation, isn't it? 
 
		