Understanding service configuration versions

Ambari creates and stores a unique configuration version when you change any property value in a config type.

It is important to understand how service configurations are organized and stored in Ambari. Properties are grouped into configuration types. A set of config types composes the set of configurations for a service.

For example, the Hadoop Distributed File System (HDFS) service includes the hdfs-site, core-site, hdfs-log4j, hadoop-env, and hadoop-policy config types. Using Ambari Web, browse to Services > HDFS > Configs, to edit the configuration properties for these config types.

Ambari performs configuration versioning at the service level. Therefore, when you modify a configuration property in a service, Ambari creates a service config version. The following figure shows version 1 (V1) and version 2 (V2) of a service configuration with a change to a property in Config Type A. When you changie a property value in Config Type A in V1, Ambari creates V2.