Rudder

User story #11618

Updated by François ARMAND over 6 years ago

We want to have a system to be able to override node properties values (or add new ones) from the node itself, by third-party system (so the values are not managed by Rudder, just use by it).  

 The values would be usable only on the node, and so in techniques or if the ${node.properties[...] | node} is used.  

 From an implementation point of view, we propose to add a @/var/rudder/local/properties.d/@ directories on node.  

 External systems can put json file into it, with the same convention as node properties json file, i.e: 

 <pre> 
 { 
   "properties":{ 
     "property_key1":"local node prop", "property_key1":"simple string value", 
     "property_key2":{ 
       "more":"local node prop", "more":"json", 
       "and":"local node prop", "and":"even more", 
     }, 
   } 
 } 
 </pre> 

 The agent then load node properties from @/var/rudder/cfengine-community/inputs/properties.d/@ and from @/var/rudder/local/properties.d/@, and merge them at the "properties"'s children level with local properties winning;  

 So if Rudder properties was:  

 <pre> 
 { 
   "properties":{ 
     "property_key0":"from rudder", 
     "property_key1":{ 
       "key1":"from rudder", "key1":"json", 
       "key2":"even more", 
     }, 
   } 
 } 
 </pre> 

 The results would be:  

 <pre> 
 { 
   "properties":{ 
     "property_key0":"from rudder", 
     "property_key1":"local node prop", "property_key1":"simple string value", 
     "property_key2":{ 
       "more":"local node prop", "more":"json", 
       "and":"local node prop", "and":"even more", 
     }, 
   } 
 } 
 </pre> 

 So property_key0 was kept from Rudder's node properties (because no override), property_key1 was overriden (from a json value to a string one in the example, but it's not mandatory to be it like that), and property_key2 was only present in local node property and was added to context.  

 

Back