only set vars and group, if non-nil

container.json

@@ -233,8 +233,6 @@
     "teamspeak": {
       "ipv4": "192.168.66.21/32",
       "ipv6": "2a01:4f8:210:31fd:1::15/128",
-      "group": null,
-      "vars": null,
       "backup-paths": [
         "var/lib/teamspeak3-server"
       ]
@@ -242,8 +240,6 @@
     "prosody": {
       "ipv4": "192.168.66.22/32",
       "ipv6": "2a01:4f8:210:31fd:1::16/128",
-      "group": null,
-      "vars": null,
       "rdns6": "jabber.higgsboson.tk",
       "backup-paths": [
         "var/lib/prosody"
@@ -279,55 +275,37 @@
     "etherpad": {
       "ipv4": "192.168.66.25/32",
       "ipv6": "2a01:4f8:210:31fd:1::19/128",
-      "group": null,
-      "vars": null
     },
     "pyload": {
       "ipv4": "192.168.66.26/32",
       "ipv6": "2a01:4f8:210:31fd:1::1a/128",
-      "group": null,
-      "vars": null
     },
     "squid": {
       "ipv4": "192.168.66.27/32",
       "ipv6": "2a01:4f8:210:31fd:1::1b/128",
-      "group": null,
-      "vars": null
     },
     "classifier": {
       "ipv4": "192.168.66.28/32",
       "ipv6": "2a01:4f8:210:31fd:1::1c/128",
-      "group": null,
-      "vars": null
     },
     "seafile": {
       "ipv4": "192.168.66.29/32",
       "ipv6": "2a01:4f8:210:31fd:1::1d/128",
-      "group": null,
-      "vars": null
     },
     "login": {
       "ipv4": "192.168.66.30/32",
       "ipv6": "2a01:4f8:210:31fd:1::1e/128",
-      "group": null,
+      "rdns6": "login.higgsboson.tk",
       "vars": {
         "ssh_ldap": true
       }
     },
-    "dn42": {
-      "ipv4": "192.168.66.31/32",
-      "ipv6": "2a01:4f8:210:31fd:1::1f/128",
-      "group": null,
-      "vars": null
-    },
     "halfcode": {
       "ipv4": "192.168.66.32/32",
       "ipv6": "2a01:4f8:210:31fd:1::20/128",
       "group": "php",
       "vars": {
-        "php_extensions": [
-
-        ]
+        "php_extensions": []
       }
     },
     "phonefinder": {
@@ -335,10 +313,8 @@
       "ipv6": "2a01:4f8:210:31fd:1::21/128",
       "group": "php",
       "vars": {
-        "php_extensions": [
-          "[@]"
-        ]
+        "php_extensions": []
       }
     }
   }
-}
+}

hooks/lib/lxc/container.rb

@@ -40,8 +40,8 @@ module Lxc
       c = @data["network"][@name] || {}
       c["ipv4"] = NetAddr::CIDR.create(@ipv4).to_s(Short: true)
       c["ipv6"] = NetAddr::CIDR.create(@ipv6).to_s(Short: true)
-      c["group"] = @options[:group]
-      c["vars"] = @options[:vars]
+      c["group"] = @options[:group] if @options[:group]
+      c["vars"] = @options[:vars] if @options[:vars]
       opts = @options.merge(name: @name,
                             ipv4: format_address(@ipv4, @ipv4_subnet.to_i(:netmask)),
                             ipv6: format_address(@ipv6, @ipv6_subnet.to_i(:netmask)))