Removing nodes

Removing a node marks the node for removal from the cluster and completely disables the node from serving any requests across the cluster.

Once a node is removed, a node is no longer part of the cluster in any way and can be switched off, or can be updated or upgraded.

Important

Before you remove a node from the cluster, ensure that you have the capacity within the remaining nodes of your cluster to handle your workload. For more information on the considerations, see Choosing when to shrink your cluster. For the best results, use swap rebalance to swap the node you want to remove out, and swap in a replacement node.

Note: Removing a node does not stop the node from servicing requests. Instead, it only marks the node ready for removal from the cluster. You must perform a rebalance operation to complete the removal process.
Warning: Occasionally, during an online upgrade, virtual machine-based configurations can swap out "old' VM nodes in place of a totally new set. If all old nodes are removed from the cluster, clients may no longer know about any nodes and fail to connect.
To prevent such problems, make sure that you provide one of the following solutions:
  • At least one of the original nodes is maintained in the cluster, and this node is listed in the client's server configuration.
  • The client's server configuration is appropriately updated to include at least one "new" node before the last old node is removed.

Like adding nodes, node can be removed either via the Web Console or CLI.

Web Console

You can remove a node from the cluster from within the Manage Server Nodes section of the Web Console, as shown in the figure below.

To remove a node, click the Remove Server button next to the node you want to remove. You will be provided with a warning to confirm that you want to remove the node. Click Remove to mark the node for removal.

Using the Command-line

You cannot mark a node for removal from the command-line without also initiating a rebalance operation. The rebalance command accepts one or more --server-add and/or --server-remove options. This adds or removes the server from the cluster, and immediately initiates a rebalance operation.

For example, to remove a node during a rebalance operation:


> couchbase-cli rebalance --cluster=127.0.0.1:8091 \
          -u Administrator -p Password \
          --server-remove=192.168.0.73