make all passwords alphanumeric, use defaults instead of vars inside roles for precedence

Change-Id: I9d521d2521a1f208addec3810b13f8c030f9dcaf
diff --git a/roles/compute-node/defaults/main.yml b/roles/compute-node/defaults/main.yml
new file mode 100644
index 0000000..8bb3905
--- /dev/null
+++ b/roles/compute-node/defaults/main.yml
@@ -0,0 +1,48 @@
+---
+
+pub_ssh_key: "{{ lookup('file', '/etc/maas/.ssh/cord_rsa.pub') }}"
+
+compute_node:
+    password: "{{password_compute_node | default(lookup('password', 'passwords/compute_node.txt chars=ascii_letters,digits'))}}"
+    fabric:
+        include:
+            names: "{{ fabric_include_names | default(omit) }}"
+            module_types: "{{ fabric_include_module_types | default('i40e, mlx4_en') }}"
+            bus_types: "{{ fabric_include_bus_types | default(omit) }}"
+        exclude:
+            names: "{{ fabric_exclude_names | default(omit) }}"
+            module_types: "{{ fabric_exclude_module_types | default(omit) }}"
+            bus_types: "{{ fabric_exclude_bus_types | default(omit) }}"
+        ignore:
+            names: "{{ fabric_ignore_names | default(omit) }}"
+            module_types: "{{ fabric_ignore_module_types | default(omit) }}"
+            bus_types: "{{ fabric_ignore_bus_types | default(omit) }}"
+    management:
+        include:
+            names: "{{ management_include_names | default(omit) }}"
+            module_types: "{{ management_include_module_types | default(omit) }}"
+            bus_types: "{{ management_include_bus_types | default(omit) }}"
+        exclude:
+            names: "{{ management_exclude_names | default(omit) }}"
+            module_types: "{{ management_exclude_module_types | default(omit) }}"
+            bus_types: "{{ management_exclude_bus_types | default(omit) }}"
+        ignore:
+            names: "{{ management_ignore_names | default(omit) }}"
+            module_types: "{{ management_ignore_module_types | default(omit) }}"
+            bus_types: "{{ management_ignore_bus_types | default(omit) }}"
+
+    interfaces:
+        fabric: "{{ fabric_iface | default('fabric') }}"
+        management: "{{ management_iface | default('mgmtbr') }}"
+        external: "{{ external_iface | default(None) }}"
+        file: "{{ iface_file | default('/etc/network/interfaces') }}"
+    addresses:
+        fabric: "{{ fabric_ip | mandatory }}"
+        management: "{{ management_ip | default('dhcp') }}"
+        external: "{{ external_ip | default('manual') }}"
+    gateway:
+        external: "{{ external_gw | default(omit) }}"
+        management: "{{ management_gw | default(omit) }}"
+    broadcast:
+        external: "{{ external_bc | default(omit) }}"
+        management: "{{ management_bc | default(omit) }}"