Merge branch 'scanner' into 'master'

usable cdist scan

See merge request ungleich-public/cdist!993

docs/src/cdist-scan.rst

@@ -0,0 +1,82 @@
+Scan
+=====
+
+Description
+-----------
+Runs cdist as a daemon that discover/watch on hosts and reconfigure them
+periodically. It is especially useful in netboot-based environment where hosts
+boot unconfigured, and to ensure your infrastructure stays in sync with your
+configuration.
+
+This feature is still consider to be in **beta** stage, and only operate on
+IPv6 (including link-local).
+
+Usage (Examples)
+----------------
+
+Discover hosts on local network and configure those whose name is resolved by
+the name mapper script.
+
+.. code-block:: sh
+
+    $ cdist scan --beta --interface eth0 \
+      --mode scan --name-mapper path/to/script \
+      --mode trigger --mode config
+
+List known hosts and exit.
+
+.. code-block:: sh
+
+    $ cdist scan --beta --list --name-mapper path/to/script
+
+Please refer to `cdist(1)` for a detailed list of parameters.
+
+Modes
+-----
+
+The scanner has 3 modes that can be independently toggled. If the `--mode`
+parameter is not specified, only `tigger` and `scan` are enabled (= hosts are
+not configured).
+
+trigger
+  Send ICMPv6 requests to specific hosts or broadcast over IPv6 link-local to
+  trigger detection by the `scan` module.
+
+scan
+  Watch for incoming ICMPv6 replies and optionally configure detected hosts.
+
+config
+  Enable configuration of hosts detected by `scan`.
+
+Name Mapper Script
+------------------
+
+The name mapper script takes an IPv6 address as first argument and writes the
+resolved name to stdout - if any. The script must be executable.
+
+Simplest script:
+
+.. code-block:: sh
+  #!/bin/sh
+
+  case "$1" in
+  	"fe80::20d:b9ff:fe57:3524")
+  		printf "my-host-01"
+  		;;
+  	"fe80::7603:bdff:fe05:89bb")
+  		printf "my-host-02"
+  		;;
+  esac
+
+Resolving name from `PTR` DNS record:
+
+.. code-block:: sh
+  #!/bin/sh
+
+  for cmd in dig sed; do
+  	if ! command -v $cmd > /dev/null; then
+  		exit 1
+  	fi
+  done
+
+  dig +short -x "$1" | sed -e 's/.$//'

docs/src/index.rst

@@ -34,6 +34,7 @@ It natively supports IPv6 since the first release.
    cdist-parallelization
    cdist-inventory
    cdist-preos
+   cdist-scan
    cdist-integration
    cdist-reference
    cdist-best-practice

docs/src/man1/cdist.rst

@@ -88,6 +88,9 @@ SYNOPSIS
     cdist info [-h] [-a] [-c CONF_DIR] [-e] [-F] [-f] [-g CONFIG_FILE] [-t]
                [pattern]
 
+    cdist scan -I INTERFACE [--m MODE] [--name-mapper PATH_TO_SCRIPT] [--list]
+               [-d CONFIG_DELAY] [-t TRIGGER_DELAY]
+
 
 DESCRIPTION
 -----------
@@ -641,6 +644,31 @@ Display information for cdist (global explorers, types).
 **-t, --types**
     Display info for types.
 
+SCAN
+----
+
+Runs cdist as a daemon that discover/watch on hosts and reconfigure them
+periodically.
+
+**-I INTERFACE, --interfaces INTERFACE**
+    Interface to listen on. Can be specified multiple times.
+
+**-m MODE, --mode MODE**
+    Scanner components to enable. Can be specified multiple time to enable more
+    than one component. Supported modes are: scan, trigger and config. Defaults
+    to tiggger and scan.
+
+**--name-mapper PATH_TO_SCRIPT**
+    Path to script used to resolve a remote host name from an IPv6 address.
+
+**--list**
+    List known hosts and exit.
+
+**-d CONFIG_DELAY, --config-delay CONFIG_DELAY**
+    How long (seconds) to wait before reconfiguring after last try (config mode only).
+
+**-t TRIGGER_DELAY, --tigger-delay TRIGGER_DELAY**
+    How long (seconds) to wait between ICMPv6 echo requests (trigger mode only).
 
 CONFIGURATION
 -------------