Clusters
Clusters are managed deployments of Couchbase Server.
In Couchbase Cloud, a cluster is a managed deployment of Couchbase Server. A cluster consists of one or more instances of Couchbase Server, each running on an independent node.
Services
A cluster is made up of one or more services. Couchbase Services are what allow you to access and maintain your data.
The following services are available:
| Service | Description |
|---|---|
Data Service |
Supports the storing, setting, and retrieving of data-items, specified by key. All clusters must run the Data Service. At least three Data Service nodes are required for a cluster to be supported in production. Refer to Data Service. |
Query Service |
Parses queries specified in the N1QL query-language, executes the queries, and returns results. The Query Service interacts with both the Data and Index services. Refer to Query Service. |
Index Service |
Creates indexes, for use by the Query service. Refer to Index Service. |
Deploying Services (Nodes)
Each instance of a service runs on its own virtual machine (sometimes referred to as a cluster node). When configuring a cluster, you’ll pick the services you want, the types of virtual machines you want those services to run on, and the number of instances you want of each service configuration.
Each service can be deployed, maintained, and provisioned independently of one another. This is sometimes referred to as Multi-Dimensional Scaling, and it allows you to do things like:
-
Deploy different services with different virtual machine types.
For example, deploying the Data service on VMs that have a large amount of memory, while deploying the Index service on VMs that have a very high storage I/O rating.
-
Scale a service up or down by adding or removing virtual machines.
For example, if resource capacity is running low for one of the services, you can add another VM to increase capacity.
-
Scale a service up or down by changing the virtual machine type of an existing VM.
For example, if you find that a service has a lot of excess resource capacity, you can change the VM type to one with lower capacity.