Suspend and resume nodes

Learn how to suspend and resume nodes in a cluster.

The suspended node state indicates that the node has been intentionally taken offline, for example for maintenance.

Prerequisites

The database must be stopped. See Stop a database.

Procedure

The following examples use ConfD through the command-line tool confd_client, which is available on all database nodes. You can also access ConfD through XML-RPC in your own Python programs. For more information, see ConfD.

Connect to COS

Connect to the cluster operating system (COS) using c4 connect -i PLAY_ID -s cos.

Example:
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./c4 connect -i c3275f84 -s cos

To find the play ID, you can use c4 ps.

For more information about how to use c4 commands, see How to use c4.

Suspend a node

To suspend a node, use the ConfD job node_suspend with the node ID. For example, to suspend node 12 in the current deployment:

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confd_client node_suspend nid: 12

Resume a node

Starting up a node will automatically unsuspend it. You can also manually unsuspend a node using the ConfD job node_resume. For example:

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confd_client node_resume nid: 12