Configuration Properties


This guide provides details on how to configure Kylo Templates and Feeds with properties from different sources. The sources can be the following:

  1. Configuration from
  2. Configuration from Feed Metadata
  3. Configuration from Nifi environment variables

There are two property resolution options:

  1. Design-time resolution
  2. Runtime resolution

1. Configuration Sources

1.1 Configuration from

When creating Kylo feeds and templates one can refer to configuration properties which appear in /opt/kylo/kylo-services/conf/ file. Property names must begin with word config. and they should be referenced by following notation in Kylo UI ${config.<property-name>}

Here is an example of how we use this in

config.props.max-file-size=3 MB

Here is how you would refer to config.props.max-file-size in Kylo template:


Setting NiFi Processor Properties

There is a special property naming convention available for Nifi Processors and Services in too.

For Processor properties four notations are available:

  1. nifi.<processor_type>.<property_key>
  2. nifi.all_processors.<property_key>
  3. nifi.<processor_type>[<processor_name>].<property_key> (Available in Kylo 0.8.1)
  4. $nifi{} will inject the NiFi property expression into the value. (Available in Kylo 0.8.1)

where <processor_type>, <property_key>, <processor_name> should be all lowercase with spaces replaced by underscores. The <processor_name> is the display name of the processor set in NiFi. Starting in Kylo 0.8.1 you can inject a property that has NiFi Expression Language as the value. Since Spring and NiFi EL use the same notation (${property}) Kylo will detect any nifi expression in the property value if it start with $nifi{property}

  • Setting properties matching the NiFi Processor Type. Here is an example of how to set ‘Spark Home’ and ‘Driver Memory’ properties on all ‘Execute Spark Job’ Processors:

  • Setting properties for a named NiFi Processor (starting in Kylo 0.8.1). Here is an example setting the property for just the ExecuteSparkJob processor named “Validate and Split Records”:

  • Setting a property with NiFi expression language as a value (starting in Kylo 0.8.1). Here is an example of injecting a value which refers to a NiFi expression


    The “my property” on the UpdateAttribute processor named “My Processor” will get resolved to /path/to/${} in NiFi.

  • Setting all properties matching the property key. Here is an example of how to set Kerberos configuration for all processors which support it:


Setting Controller Service Properties

For Services use following notation: nifi.service.<service_name>.<property_name>. Anything prefixed with nifi.service will be used by the UI. Replace spaces in Service and Property names with underscores and make it lowercase. Here is an example of how to set ‘Database User’ and ‘Password’ properties for MySql Service:


1.2 Configuration from Feed Metadata

When creating Kylo feeds and templates you can also refer to Feed Metadata, i.e. set property values based on known information about the feed itself. These properties start with word ‘metadata’, e.g. ${metadata.<property-name>}

Here is how you would refer to Category name and Feed name in Kylo template:


1.3 Configuration from Nifi environment variables

TODO - Help us complete this section

2. Property Resolution Options

2.1 Design-time Resolution

These properties will be resolved at design-time during Feed creation from Template. They use the following notation ${property-name}. If you had property-name=value in and ${property-name} in Template then static value would be placed into Processor field in Nifi on Feed creation.

You can also provide nested properties or properties which refer to other properties ${property-name2.${property-name1}} If you had property-name1=value1 and property-name2.value1=value2 in and ${property-name1.${property-name2}} in Template then static value2 would be placed into Processor field in Nifi on Feed creation.


This type of resolution is great for properties which do not support Nifi’s Expression Language.

2.2 Runtime or Partial Resolution

If you don’t want to resolve properties at design time and would rather take advantage of property resolution at runtime by Nifi’s Expression Language then you can still refer to properties in Kylo Feeds and Template, just escape them with a dollar sign $ like so: $${config.${metadata.feedName}.input-dir}. Notice the double dollar sign at the start. This property will be resolved at design-time to ${config.<feed-name>.input-dir} and will be substituted at runtime with a value from file. So if you had a feed called users and config.users.input-dir=/var/dropzone/users in then at runtime the feed would take its data from /var/dropzone/users directory.



This type of resolution is great for creating separate configurations for multiple feeds created from the same template