Top-Level Goal

The top-level goal is a single API for managing cluster configuration.

The beneficiaries of this work are those who want to change the configuration of the cluster (create/destroy regions, indices or gateway receivers/senders etc), and have these changes replicated on all the applicable servers and persisted in the cluster configuration service. In addition to developers building Geode-based applications, the target user group includes developers working on different parts of the Geode code such as Spring Data for Apache, queries for Lucene index, or storage for the JDBC connector.

Problem Statement

In the current implementation:

• Most cluster configuration tasks are possible, but only by coordinating XML file-based configuration files, properties files, and gfsh commands. 
• Many of the desired outcomes are achievable through multiple paths.
• Establishing a consistent configuration and persisting it across the cluster is difficult, sometimes impossible.

Product Goals 

The developer should be able to:

• Create regions/indices on the fly.

• Persist the configuration and apply it to the cluster (when a new node joins, it has the config; when the server restarts, it has the config)

• Obtain a consistent view of the current configuration

• Apply the same change to the cluster in the same way

• Be able to change the configuration in one place

• Obtain this configuration without being on the cluster

Proposed Solution

The proposed solution includes:

• Address the multiple path issue by presenting a single public API for configuring the cluster, including such tasks as creating a region  destroying an index, or update an async event queue.
• Provide a means to persist the change in the cluster configuration.
• Save a configuration to the Cluster Management Service without having to restart the servers
• Obtain the cluster management service from a cache when calling from a client or a server
• Pass a config object to the cluster management service
• Use CRUD operations to manage config objects

This solution should meet the following requirements:

• The user needs to be authenticated and authorized for each API call based on the resource he/she is trying to access.

  • Enable Security Manager with Finer Grained Security

• User can call the API from either the client side or the server side.

• The outcome (behavior) is the same on both client and server:

•  affects cluster wide

•  idempotent

What We Have Now

Our admin rest API "sort of" already serves this purpose, but it has these shortcomings:

1. It's not a public API
2. The API is restricted to the operations implemented as gfsh commands, as the argument to the API is a gfsh command string.
3. Each command does similar things, yet commands may not be consistent with each other.

Below is a diagram of the current state of things:

From the current state of commands, It's not easy to extract a common interface for all the commands. And developers do not want to use gfsh command strings as a "makeshift" API to call into the command. We are in need of a unified interface and a unified workflow for all the commands.

Proposal

We propose a new Cluster Management Service (CMS) which has two responsibilities:

• Update runtime configuration of servers (if any running)
• Persist configuration (if enabled)

Note that in order to use this API, Cluster Configuration needs to be enabled.

The CMS API is exposed as a new endpoint as part of "Admin REST APIs", accepting configuration objects (JSON) that need to be applied to the cluster. CMS adheres to the standard REST semantics, so users can use POST, PATCH, DELETE and GET to create, update, delete or read, respectively. The API returns a JSON body that contains a message describing the result along with standard HTTP status codes.

Root End Point

{
    "number_of_locators": 3,
	"number_of_servers": 8,
	"region_url": "/geode/v2/regions",
	"gateway_receiver_url": "/geode/v2/gwr",
	"gateway_sender_url": "/geode/v2/gws"
}

{
    "message": "Missing authentication credential header(s)"
}

{
    "message": "User1 not authorized for CLUSTER:READ"
}

Create End Point

{
  "regionConfig": {
      "name": "Foo",
      "type": "REPLICATE" 
  }
}

{
  "Metadata": {
    "Url": "/geode/v2/regions/Foo"
  }
}

{
  "message": "Region /Foo already exists"
}

{
    "message": "Region type is a required parameter"
}

{
    "message": "Missing authentication credential header(s)"
}

{
    "message": "User1 not authorized for DATA:MANAGE"
}

{
    "message": "Failed to create region /Foo because of <reason>"
}

Note that the CREATE endpoint is idempotent – i.e. it should be a NOOP if the region already exists.

List End Point

{
    "Total_results": 10,
    "Regions" : [
     {
       "Name": "Foo",
       "Url": "/geode/v2/regions/Foo"
     },
     ...
     ]
}

{
    "message": "Missing authentication credential header(s)"
}

{
    "message": "User1 not authorized for CLUSTER:READ"
}

Describe End Point

{
    "Name": "Foo",
    "Data_Policy": "partition",
    "Hosting_Members": [
      "s1",
      "s2",
      "s3"
      ],
    "Size": 0,
    "Indices": [
     {
     "Id": 111,
     "Url": "/geode/v2/regions/Customer/index/111"
     }
    ]

}

{
    "message": "Missing authentication credential header(s)"
}

{
    "message": "User1 not authorized for CLUSTER:READ"
}

{
     "message": "Region with name '/Foo' does not exist"
}

Update End Point

{
  "regionConfig": {
      "gateway_sender_id": ["1","2"]
  }
}

{
  "Metadata": {
    "Url": "/geode/v2/regions/Foo"
  }
}

{
    "message": "Invalid parameter specified"
}

{
    "message": "Missing authentication credential header(s)"
}

{
    "message": "User1 not authorized for DATA:MANAGE"
}

{
    "message": "Region with name '/Foo' does not exist"
}

{
    "message": "Failed to update region /Foo because of <reason>"
}

Delete End Point

{
    "message": "Region with name '/Foo' does not exist"
}

{
    "message": "Missing authentication credential header(s)"
}

{
    "message": "User1 not authorized for DATA:MANAGE"
}

{
    "message": "Failed to delete region /Foo because of <reason>"
}

Note that the DELETE endpoint is idempotent – i.e. it should be a NOOP if the region does not exist.

Let's look at some code to see how users can use this service. The below example shows how to create a region using CMS.

Curl (any standard REST client)

curl http://locator.host:8080/geode/v2/regions -XPOST -d '
{
  "regionConfig": {
      "name": "Foo" 
      "type": "PARTITIONED"
  }
}'

On Client