You can remove Ozone DataNodes from the CDP cluster in a controlled manner using
Cloudera Manager for performing maintenance operations. If you want to remove the DataNodes
permanently or for an unknown duration, you can decommission them. If you want to make the
DataNodes unavailable for a short period of time, such as, for a few days or hours, you can
place them in offline mode.
When you initiate the process of decommissioning a DataNode, Ozone automatically ensures
that all the storage containers on that DataNode have an additional copy created on
another DataNode before the decommission completes. Similarly, when you initiate the
process of placing a DataNode in offline mode, Ozone ensures that at least two copies of
the DataNode's storage containers are present on other nodes before the particular
DataNode enters offline mode.
You can also recommission a DataNode that is already decommissioned or placed in offline
mode. When you recommission such a DataNode, Ozone automatically removes any excess
containers created during the decommission or offline process.