integrate new example into microvms-host.nix example

Author: RobWalt

examples/host-static-guest.nix

@@ -10,7 +10,19 @@ nixpkgs.lib.nixosSystem {
     # this runs as a MicroVM that nests MicroVMs
     self.nixosModules.microvm
 
-    ({ config, lib, pkgs, ... }: {
+    ({ config, lib, pkgs, ... }:
+    let
+      hypervisors-with-mac = builtins.listToAttrs(
+        map (hypervisor:
+          let
+            hash = builtins.hashString "sha256" hypervisor;
+            c = off: builtins.substring off 2 hash;
+            mac = "${builtins.substring 0 1 hash}2:${c 2}:${c 4}:${c 6}:${c 8}:${c 10}";
+          in
+          { name = hypervisor; value = mac; })
+        self.lib.hypervisors);
+    in
+    {
       networking.hostName = "microvms-host";
       system.stateVersion = config.system.nixos.version;
       users.users.root.password = "";
@@ -38,38 +50,30 @@ nixpkgs.lib.nixosSystem {
       };
 
       # Nested MicroVMs (a *host* option)
-      microvm.vms = builtins.listToAttrs (
-        map (hypervisor: {
-          name = hypervisor;
-          value = {
-            config = {
-              system.stateVersion = config.system.nixos.version;
-              networking.hostName = "${hypervisor}-microvm";
+      microvm.vms = builtins.mapAttrs (hypervisor: mac:
+        {
+          config = {
+            system.stateVersion = config.system.nixos.version;
+            networking.hostName = "${hypervisor}-microvm";
 
-              microvm = {
-                inherit hypervisor;
-                interfaces = [ {
-                  type = "tap";
-                  id = "vm-${builtins.substring 0 12 hypervisor}";
-                  mac =
-                    let
-                      hash = builtins.hashString "sha256" hypervisor;
-                      c = off: builtins.substring off 2 hash;
-                    in
-                      "${builtins.substring 0 1 hash}2:${c 2}:${c 4}:${c 6}:${c 8}:${c 10}";
-                } ];
-              };
-              # Just use 99-ethernet-default-dhcp.network
-              systemd.network.enable = true;
+            microvm = {
+              inherit hypervisor;
+              interfaces = [ {
+                type = "tap";
+                id = "vm-${builtins.substring 0 12 hypervisor}";
+	        inherit mac;
+              } ];
+            };
+            # Just use 99-ethernet-default-dhcp.network
+            systemd.network.enable = true;
 
-              users.users.root.password = "";
-              services.openssh = {
-                enable = true;
-                settings.PermitRootLogin = "yes";
-              };
+            users.users.root.password = "";
+            services.openssh = {
+              enable = true;
+              settings.PermitRootLogin = "yes";
             };
           };
-        }) self.lib.hypervisors);
+        }) hypervisors-with-mac;
 
       systemd.network = {
         enable = true;
@@ -85,6 +89,16 @@ nixpkgs.lib.nixosSystem {
             DHCPServer = true;
             IPv6SendRA = true;
           };
+          dhcpServerStaticLeases =
+            [
+	      # Let DHCP assign a statically known address to the qemu vm
+              {
+                dhcpServerStaticLeaseConfig = {
+                  MACAddress = hypervisors-with-mac.qemu;
+                  Address = "10.0.13.37";
+                };
+              }
+            ];
           addresses = [ {
             addressConfig.Address = "10.0.0.1/24";
           } {

examples/microvms-host.nix

@@ -47,7 +47,6 @@
             };
           in {
             vm = nixosToApp ./examples/microvms-host.nix;
-            host-static-guest = nixosToApp ./examples/host-static-guest.nix;
             qemu-vnc = nixosToApp ./examples/qemu-vnc.nix;
             graphics = {
               type = "app";