| # Stacks and Services |
| |
| **Introduction** |
| |
| Ambari supports the concept of Stacks and associated Services in a Stack Definition. By leveraging the Stack Definition, Ambari has a consistent and defined interface to install, manage and monitor a set of Services and provides extensibility model for new Stacks + Services to be introduced. |
| |
| From Ambari 2.4, there is also support for the concept of Extensions and its associated custom Services in an Extension Definition. |
| |
| Terminology |
| |
| Term | Description |
| -----|------------ |
| Stack | Defines a set of Services and where to obtain the software packages for those Services. A Stack can have one or more versions, and each version can be active/inactive. For example, Stack = "HDP-1.3.3". |
| Extension | Defines a set of custom Services which can be added to a stack version. An Extension can have one or more versions. |
| Service | Defines the Components (MASTER, SLAVE, CLIENT) that make up the Service. For example, Service = "HDFS" |
| Component | The individual Components that adhere to a certain defined lifecycle (start, stop, install, etc). For example, Service = "HDFS" has Components = "NameNode (MASTER)", "Secondary NameNode (MASTER)", "DataNode (SLAVE)" and "HDFS Client (CLIENT)" |
