Chapter 6. Expanding the Cluster
Once the initial cluster is running and in an active+clean state, add additional OSD nodes and Ceph Object Gateway nodes to the cluster. Apply the steps detailed in Tuning the Kernel to each node. See the Adding and Removing OSD Nodes section in the Red Hat Ceph Storage 3 Administration Guide for details on adding nodes.
For each OSD node added to the cluster, add OSDs to the cluster for each drive in the node that will store client data. See the Adding an OSD section in the Red Hat Ceph Storage 3 Administration Guide for additional details. When using Ansible to add OSD nodes, see Configuring Ansible Groups, and add the OSD nodes to the appropriate group if the cluster will support multiple use cases.
For each Ceph Object Gateway node, install a gateway instance. For details, see the Installing the Ceph Object Gateway section in the Red Hat Ceph Storage 3 Installation Guide for Red Hat Enterprise Linux.
Once the cluster returns to an active+clean state, remove any overrides and proceed with Developing Storage Strategies.
Step 3 of Adding a Node and Step 10 of Adding an OSD With the Command Line Interface will be revisited in topics beginning with Developing CRUSH Hierarchies.

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