Adding a Node

Adding a Node

Add a node to the cluster during initial installation or after the installation.

Full Administrators and Cluster Administrators can use the UI, CLI, or REST API interface to add a node.

There are several methods for adding a node to a cluster. In each case, one or more nodes are marked to be added to the cluster, but it doesn't become an active member of the cluster until you rebalance the cluster.

In a CLI call, the rebalance can optionally be done while adding the new node and using the UI, rebalancing requires an extra step.

During Initial Installation

When setting up a new Couchbase Server installation, you have the option to join the new node to an existing cluster. For detailed instructions, see Initialize the Cluster.

The node will be created as a new cluster, but the pending status of the node within the new cluster will be indicated, as shown in the example below:

Using the UI

Using the same method, you can add a server that was previously part of this or another cluster. During this process, Couchbase Server must be running.

To add a new node to an existing cluster using the Web Console:

  1. From the Couchbase Web Console > Servers > click Add Server.
  2. Enter the following information and click Add Server.
Option Description
Server IP Address The IP address or FQDN (Fully Qualified Domain Name) of the server that you want to add. It is preferred that you use FQDNs, especially in a cloud hosting environment.
Assign Server Group Select the server group name from the list. For more information about server groups, see Manage Server Groups.
Username The username of the administrator account of the node to be added.
Password The password of the administrator account of the node to be added.
Services Select the appropriate check box to define the kind of services will be provided on the server node that's been added. You can add one, two, or all four services. The options are: Data Service, GSI Service, FTS Service, and Query Service.

A warning will appear indicating that the operation is destructive on the destination server. Any data currently stored on the server will be deleted, and if the server is currently part of another cluster, it will be removed and marked as failed over in that cluster.

Once the information has been entered successfully, the node will be marked as ready to be added to the cluster, and the cluster's pending rebalance count will be updated.

Important: Once a node is added with a specific service, you cannot change the type of services on that node. You must remove the node, rebalance, and then add it back to the cluster with the services of your choice.

Using the CLI

Use CLI to add one or more nodes to an existing cluster.

The new nodes must have Couchbase Server installed, and Couchbase Server must be running on each node.

To add a node:
> couchbase-cli server-add \
            --cluster=localhost:8091  --user cluster-username --password cluster-password \    
            --server-add=192.168.0.72:8091  --server-add-username=node-username \ 
            --server-add-password=node-password \
            --services=data,index,query

where:

Table 1. CLI parameters for adding a node
Parameter Description
--cluster The IP address of a node in the existing cluster.
--user The username for the existing cluster.
--password The password for the existing cluster.
--server-add The IP address of the node to be added to the cluster.
--server-add-username The username of the node to be added.
--server-add-password The password of the node to be added.

If adding was successful, you will see the following response: SUCCESS: server-add 192.168.0.72:8091

If you receive a failure message, you will be notified of the type of failure. You can add multiple nodes in one command by supplying multiple --server-add command-line options to the command.

Note: Once a node has been successfully added, the Couchbase Server cluster indicates that a rebalance is required to complete the operation.
Here’s an example of cluster rebalance after adding a new node: Request syntax with rebalancing:
couchbase-cli rebalance
            -c [localhost]:8091
            --server-add=[host]:8091
            --server-add-username=[administrator]
            --server-add-password=[password]     

You can cancel the addition of a node to a cluster without having to perform a rebalance operation. Canceling the operation removes the server from the cluster without having transferred or exchanged any data, since no rebalance operation took place. You can cancel the operation using the Couchbase Web Console.

Using the REST API

With the REST API, you can add nodes to the cluster by providing the IP address, administrator username, and password as part of the data payload.
Use the curl command to add a new node. If you are adding another service than data, which is the default, specify that service index or n1ql:
> curl -u cluster-username:cluster-password localhost:8091/controller/addNode\
          -d "hostname=192.168.0.68&user=node-username&password=node-password&services=n1ql"