dc_as_zone: add dirty hack for using datacenter as zone

.gitignore

@@ -8,6 +8,9 @@ CMakeFiles
 cmake_install.cmake
 *.dylib
 *.idea
+*.vscode
+cluster.genin.yml
+inventory.yml
 __pycache__
 *pyc
 .cache

src/task/cluster.rs

@@ -628,7 +628,7 @@ impl Cluster {
     /// - that's it, when there may only be single domain name in instance's `failure_domains`.
     pub fn use_failure_domain_as_zone_for_instances(mut self, args: &ArgMatches) -> Self {
         if args.get_flag("fd-as-zone") {
-            self.hosts.use_failure_domain_as_zone();
+            self.hosts.use_failure_domain_as_zone(None);
         }
         self
     }

src/task/cluster/hst/test.rs

@@ -515,7 +515,7 @@ fn hosts_use_failure_domain_as_zone() {
     assert_eq!(failure_domain_instance_zone(&host, "cache-2-1"), None);
     assert_eq!(failure_domain_instance_zone(&host, "cache-2-2"), None);
 
-    host.use_failure_domain_as_zone();
+    host.use_failure_domain_as_zone(None);
     assert_eq!(
         failure_domain_instance_zone(&host, "cache-2-1"),
         Some("dc-2")

src/task/cluster/hst/v2.rs

@@ -774,14 +774,25 @@ impl HostV2 {
     }
 
     /// For every instance that has finalized failure domain, replace its zone with that domain name.
-    pub fn use_failure_domain_as_zone(&mut self) {
+    pub fn use_failure_domain_as_zone(&mut self, dc: Option<String>) {
+        let dc = if dc.is_some() {
+            dc
+        } else if self.name == Name::from("cluster") {
+            None
+        } else {
+            Some(self.name.to_string())
+        };
         for instance in self.instances.iter_mut() {
             if let FailureDomains::Finished(failure_domain) = &instance.failure_domains {
-                instance.config.zone = Some(failure_domain.clone());
+                if let Some(dc) = &dc {
+                    instance.config.zone = Some(dc.clone());
+                } else {
+                    instance.config.zone = Some(failure_domain.clone());
+                }
             }
         }
         for sub_host in self.hosts.iter_mut() {
-            sub_host.use_failure_domain_as_zone()
+            sub_host.use_failure_domain_as_zone(dc.clone())
         }
     }