doc: describe nocloud network-config v2 subset

README.md

@@ -41,6 +41,13 @@ instance:
 
 Other cloud specific and user-data handler specific actions may also occur.
 
+For the NoCloud provider, Tiny Cloud also supports a subset of
+`network-config` version 2. The currently supported keys are:
+`version: 2`, `ethernets`, `dhcp4`, `dhcp6`, `accept-ra`,
+`match.macaddress`, `set-name`, `addresses`, `gateway4`, `gateway6`,
+`nameservers.addresses`, `dhcp4-overrides.route-metric`, and
+`dhcp6-overrides.route-metric`.
+
 Also included is a handy `imds` client script for easy access to an instance's
 IMDS data.
 

docs/tiny-cloud.8.scd

@@ -74,6 +74,35 @@ Otherwise, the selected phase action list is loaded from the tiny-cloud init
 library. Each action is run in order. If an action fails, *tiny-cloud* exits
 with a non-zero status.
 
+# NOCLOUD NETWORKING
+
+For the *nocloud* provider, *tiny-cloud* supports the legacy
+*meta-data* *network-interfaces* and a subset of NoCloud
+*network-config* version 2.
+
+Supported *network-config* keys are:
+
+- *version: 2*
+- *ethernets*
+- *dhcp4*
+- *dhcp6*
+- *accept-ra*
+- *match.macaddress*
+- *set-name*
+- *addresses*
+- *gateway4*
+- *gateway6*
+- *nameservers.addresses*
+- *dhcp4-overrides.route-metric*
+- *dhcp6-overrides.route-metric*
+
+When `match.macaddress` and `set-name` are used, *tiny-cloud* writes
+_/etc/iftab_, configures _/etc/conf.d/macifrename_ to use it, and enables
+and starts the `macifrename` OpenRC service if available.
+
+Unsupported `network-config` versions or unsupported v2 layouts are ignored
+with a warning, and normal network fallback behavior applies.
+
 # FILES
 
 _/etc/tiny-cloud.conf_
@@ -82,6 +111,16 @@ _/etc/tiny-cloud.conf_
 _/etc/tiny-cloud.disabled_
 	When present, suppresses phase execution.
 
+_/etc/network/interfaces_
+	Generated network interface configuration.
+
+_/etc/iftab_
+	MAC-based interface rename rules generated from NoCloud *network-config*
+	version 2.
+
+_/etc/conf.d/macifrename_
+	OpenRC service configuration used when _/etc/iftab_ is generated.
+
 _/var/lib/cloud/.bootstrap-complete_
 	Bootstrap completion marker.