Add a recipe to install the zerotier ohai plugin

The attributes are saved as "automatic" attributes and look like this:

  "zerotier": {
    "version": "1.16.2",
    "node_id": "NODEID",
    "networks": {
      "NETWORKID": {
        "network_name": "networkname",
        "mac": "ff:ff:ff:ff:ff:ff",
        "status": "OK",
        "type": "PRIVATE",
        "interface": "abcdefg",
        "addresses": [
          "10.1.1.255/24"
        ]
      }
    }
  }

Refs #263

site-cookbooks/kosmos_zerotier/metadata.rb

@@ -4,7 +4,8 @@ maintainer_email 'mail@kosmos.org'
 license 'MIT'
 description 'Installs/Configures zerotier'
 long_description 'Installs/Configures zerotier'
-version '0.1.0'
+version '0.2.0'
 chef_version '>= 14.0'
 
 depends 'kosmos-base'
+depends 'zerotier'

site-cookbooks/kosmos_zerotier/recipes/ohai_plugin.rb

@@ -0,0 +1,21 @@
+#
+# Cookbook:: kosmos_zerotier
+# Recipe:: ohai_plugin
+#
+
+include_recipe "zerotier::ohai_plugin"
+
+ohai "reload_zerotier" do
+  action :reload
+  plugin "zerotier"
+  notifies :run, "ruby_block[save_chef_zero_node]", :delayed
+end
+
+# Force save the node back to disk in Chef Zero
+ruby_block "save_chef_zero_node" do
+  block do
+    node.save
+    Chef::Log.info("Node #{node.name} saved to disk with ZeroTier data")
+  end
+  action :nothing
+end