added ssh host output

ohpc-instance/main.tf

@@ -39,4 +39,8 @@ resource "openstack_compute_floatingip_associate_v2" "ohpc" {
     user        = var.ohpc_user
     private_key = file(var.ssh_private_key)
   }
+}
+
+output "ssh_host" {
+    value = format(var.host_prefix,element(split(".", var.floating_ip_ohpc),3,),)
 }
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