[microvms] fix #39 Microvms are not persistent

machines/configuration.nix

@@ -45,12 +45,32 @@ let
     inputs.microvm.nixosModules.microvm
     {
       microvm = {
-        hypervisor = "qemu";
+        hypervisor = "cloud-hypervisor";
-        shares = [ {
+        mem = 2560;
-          tag = "ro-store";
+        shares = [
-          source = "/nix/store";
+          {
-          mountPoint = "/nix/.ro-store";
+            source = "/nix/store";
-        } ];
+            mountPoint = "/nix/.ro-store";
+            tag = "store";
+            proto = "virtiofs";
+            socket = "store.socket";
+          }
+          {
+            source = "/var/lib/microvms/${hostName}/etc";
+            mountPoint = "/etc";
+            tag = "etc";
+            proto = "virtiofs";
+            socket = "etc.socket";
+          }
+          {
+            source = "/var/lib/microvms/${hostName}/var";
+            mountPoint = "/var";
+            tag = "var";
+            proto = "virtiofs";
+            socket = "var.socket";
+          }
+        ];
+
         interfaces = [
           {
             type = "tap";