Update README.md

README.md

@@ -21,6 +21,16 @@ MetaCentrum OpenStack cloud Terraform use-case examples.
 
 ## Use cases
 
-### Create Linux VM server instances, each with FIP address `linux-vm-instances`
+### Create Linux VM server instances, each with FIP address [`linux-vm-instances`](linux-vm-instances)
 
-### Create Linux VM server instances, each with FIP address `windows-vm-instances`
+ * create [`instances_count`](common/modules/vm-instances/variables.tf) Linux VM instances
+   * you may costomize VM size (`instances_ostack_flavor`) and VM operating system (`instances_ostack_image`)
+ * create internal dedicated network for them ([`instances_ostack_network_cidr`](common/modules/vm-instances/variables.tf))
+ * each VM instance may have additional OpenStack volume ([`instances_volume_(size|count)`](common/modules/vm-instances/variables.tf))
+ * each VM gets FIP (floating IP address) from pool ([`instances_ostack_fip_pool`](common/modules/vm-instances/variables.tf))
+ * security groups are assigned to each VM ([`secgroup_rules.tf`](common/modules/vm-instances/secgroup_rules.tf))
+
+
+### Create Windows VM server instances, each with FIP address [`windows-vm-instances`](windows-vm-instances)
+
+Similar as above.