Trove-Replication-And-Clustering-API

Clustering and Replication

A cluster is an independent service type.

• This simplifies the configurations (ties to service_type)
• The guest impl can be different for each service_type
• We don't need cluster type and service_type when defining a cluster

Think: A instance is an instance is a cluster is an instance is NOT replication

CLUSTERING

Definition of cluster for purposes of Trove:
A cluster must provide

• High Availablility
• Fault Tolerance

A cluster object is represented as an instance with a metadata attribute containing node information. A node is a sub-resource of a cluster and has a limited number of actions that can be performed on them. A cluster is made of of equal sized nodes using all the same flavor/disk size.

Cluster Operations

Create cluster:

Create a cluster with flavor X and size Y. All nodes are of equal size.
POST /instance

{
	"name": "foobar",
	"flavor": "{flavor_id}",
	"service_type": "{service_type_id}",
	"size": 50,
	"metadata": {
		"nodes": 5,
	}
}

Delete cluster:

• Deletes all nodes in the cluster and the cluster itself.

DELETE /instance/{id}

Downsize a cluster (Delete nodes): PATCH /instance/{id}

{
	"metadata" {
		"nodes": 3
	}
}

Restart a cluster:

POST /instance/{id}/restart

{
	"empty body?"
}

Resize a cluster:

POST /instance/{id}/resize

{
	"flavor": "flavor_id",
	"volume": {
		"size": 100
	}
}

Initialize cluster:

POST /instance/{id}/initialize

{
	"pertinent data should go here..."
}

Rebalance/restripe cluster:

POST /instance/{id}/rebalance

{
	"pertinent data goes here"
}

Node Operations:

Restart a node:

POST /instance/{id}/node/{id}/restart

{
	"empty body?"
}

Initialize a node:

POST /instance/{id}/node/{id}/initialize

{
	"empty body?"
}

REPLICATION

We think of replication as a capability of some service types. Not every service type will have this capability and it should be configurable via the service types capabilities feature.

What you cannot do: - create a master and slave in one call - one call per action means simplified workflow

Replication workflow: 1. Create an instance 2. Create an Nth instance with - metadata {"master_instance": "id from 1", "replication_type": "typeid from replication_types api"} - Caveat: adding a replicated slave will alter data on the master instance and will use the agent to create the replication.

Replication Operations

Create Replication:

POST /instance

{
	"name": "foobar",
	"flavor": "flavor_id",
	"service_type": "mysql-5.1",
	"size": 50,
	"metadata": {
		"replication_type": "replication_type_id",
		"replication_data": {
			"master_instance": "instance_uuid"
		}
	}
}