diff --git a/modules/cluster/customization/default.nix b/modules/cluster/customization/default.nix
index 5bae7c7b..e03f9444 100644
--- a/modules/cluster/customization/default.nix
+++ b/modules/cluster/customization/default.nix
@@ -62,6 +62,12 @@ in
         inherit mountPoint source;
       }) config.deployment.extraShares;
     volumes = [ {
+      image = config.skyflake.deploy.rbds.root.path;
+      mountPoint = "/";
+      # don't let microvm.nix create an image file
+      autoCreate = false;
+      size = 0;
+    } {
       image = writableStoreOverlayImage;
       mountPoint = config.microvm.writableStoreOverlay;
       size = 8 * 1024;
@@ -84,6 +90,12 @@ in
         weight = 10 + i;
       }) 10);
     };
+    deploy.rbds.root = {
+      pool = "microvms";
+      namespace = "${user}-${repo}";
+      name = "${vmName}-root";
+      size = config.deployment.rootSize;
+    };
   };
 
   networking = {
diff --git a/modules/cluster/default.nix b/modules/cluster/default.nix
index d1797901..93eca954 100644
--- a/modules/cluster/default.nix
+++ b/modules/cluster/default.nix
@@ -87,6 +87,9 @@ in {
       mons = [ "server8" "server9" "server10" ];
       mgrs = mons;
       mdss = mons;
+      rbdPools.microvms = {
+        params = { size = 2; class = "ssd"; };
+      };
 
       monKeyring = config.sops.secrets."ceph/monKeyring".path;
       adminKeyring = config.sops.secrets."ceph/adminKeyring".path;