Cloning a Node¶
When you intend to grow your cluster, it might be interesting to clone the existing node prior to changing the cluster configuration. Once the cluster configuration is changed to two nodes, both nodes need to accept an update before it will be accepted. If the first node contains a lot of data, the second node must perform a large catchup operation (to make it in sync with the original node) before it accepts new updates. During the catchup period no new values can be added nor updated.
To minimize the catchup window, you can clone a node in the cluster before the configuration is changed. This way the catchup procedure is limited to the updates that were added since the moment of cloning.
To add a clone, you first need to add a node to the cluster as shown in the Configuring Arakoon section:
newcluster = q.manage.arakoon.getCluster('Demo_Cluster') newcluster.addNode(name='Node_4', ip='192.168.1.4', clientPort=7083, messagingPort=10003) newcluster.addLocalNode('Node_4') newcluster.createDirs('Node_4')
After creating the new node, simply call the catchupOnly function on the cluster object to clone a node:
To clone a node via the Arakoon CLI, see Arakoon CLI.