This is a work in progress, some of which will be reverted like overlay handling.

etc/nodes.conf

@@ -1,15 +1,36 @@
+profiles:
+  default:
+    vnfs: docker://warewulf/centos-8
+    kernel version: 3.10.0-1127.el7.x86_64
+    kernel args: crashkernel=no quiet
+    runtime overlay files:
+      - path: /etc/passwd
+        source: /path/to/source/etc/ssh/sshd.conf-node2
+        mode: 0644
+      - path: /etc/
+        mode: 0755
+        directory: true
+      - path: /etc/sshd.conf
+        source: /path/to/source/etc/ssh/sshd.conf-node2
+        mode: 0644
+      - path: /etc/link
+        source: /path/to/source/
+        mode: 0644
+        link: true
+  test:
+    runtime overlay files:
+      - path: /this/is/a/test/file
+        source: /path/to/source/etc/ssh/sshd.conf-node2
+        mode: 0644
+
 nodegroups:
   default:
     comment: This is the default group
-    vnfs: docker://warewulf/centos-8
-    runtime overlay: default
     domain suffix: default
-    kernel version: ""
-    kernel args: crashkernel=no quiet
     nodes:
       n0000:
         hostname: n0000
-        kernel args: crashkernel=no
+        profiles: [default, test]
         netdevs:
           eth0:
             hwaddr: 00:0c:29:23:8b:48
@@ -25,6 +46,7 @@ nodegroups:
       n0001:
         hostname: n0001
         ipmi ipaddr: x.x.x.x
+        kernel version: BOOO
         netdevs:
           eth0:
             hwaddr: aa:bb:cc:dd:ee:b0