Add templating of network interfaces

Closes #1

group_vars/default/base.yml

@@ -1,17 +1,69 @@
 ---
-# Basic information
+# Cluster domain for node FQDNs
 local_domain: upstream.local
+
+# IPMI user and password
+# > For the password, use pwgen to generate.
+# > Set these in the IPMI configuration as a user with permissions to reboot the host.
 username_ipmi_host: pvc
-passwd_ipmi_host: ""            # Use pwgen to generate (set in IPMI config)
-passwdhash_root: ""             # Use pwgen to generate and openssl passwd -1 -salt xyz <pw> to hash
-# Logrotate
+passwd_ipmi_host: ""
+
+# Root user password (as /etc/shadow hash)
+# > Use pwgen to generate and openssl passwd -1 -salt xyz <pw> to hash.
+passwdhash_root: ""
+
+# Log rotation configuration
 logrotate_keepcount: 7
 logrotate_interval: daily
-# Email
+
+# Root email name (usually "root")
 username_email_root: root
-# Administrative users
+
+# Administrative shell users for the cluster
 admin_users:
   - name: "myuser"
     uid: 500
     keys:
       - "ssh-ed25519 MyKey 2019-06"
+
+# Node network definitions (used by /etc/network/interfaces and PVC)
+# > The "type" can be one of three NIC types: "nic" for raw NIC devices, "bond" for ifenslave bonds,
+#   or "vlan" for vLAN interfaces. The PVC role will write out an interfaces file matching these specs.
+# > Three names are reserved for the PVC-specific interfaces: upstream, cluster, and storage; others
+#   may be used at will to describe the other devices.
+# > All devices should be using the newer device name format (i.e. enp1s0f0 instead of eth0).
+# > In this example configuration, the "upstream" device is an LACP bond of the first two onboard NICs,
+#   with the two other PVC networks being vLANs on top of this device.
+# > Usually, the Upstream network provides Internet connectivity for nodes in the cluster, and all
+#   nodes are part of it regardless of function for this reason; an optional, advanced, configuration
+#   will have only coordinators in the upstream network, however this configuration is out of the scope
+#   of this role.
+networks:
+  "upstream":
+    device: "bondU"
+    type: "bond"
+    bond_mode: "802.3ad"
+    bond_devices:
+      - "enp1s0f0"
+      - "enp1s0f1"
+    mtu: 1500
+    domain: "{{ local_domain }}"
+    subnet: "192.168.100.0/24"
+    floating_ip: "192.168.100.10/24"
+    gateway_ip: "192.168.100.1"
+  "cluster":
+    device: "vlan1001"
+    type: "vlan"
+    raw_device: "bondU"
+    mtu: 1500
+    domain: "pvc-cluster.local"
+    subnet: "10.0.0.0/24"
+    floating_ip: "10.0.0.254/24"
+  "storage":
+    device: "vlan1002"
+    type: "vlan"
+    raw_device: "bondU"
+    mtu: 1500
+    domain: "pvc-storage.local"
+    subnet: "10.0.1.0/24"
+    floating_ip: "10.0.1.254/24"