In-Place and Restore
Review the activities involved in ensuring important metadata and data are stored on a volume that is not being used by the operating system, and leveraging component high availability to maintain maximum cluster availability before starting the upgrade to HDP intermediate bits.
This option should be used in medium to large clusters (25 or more nodes), with operational teams that have environment automation experience, and have followed best practices when setting up component High Availability and HDP directory structures (such as ensuring that the HDP component data and metadata are not stored on the root volume).
This option involves going through each host in the cluster and ensuring important metadata and data are stored on a volume that is not being used by the operating system, and leverages component high availability to maintain maximum cluster availability. When visiting each host, the host is shut down, the operating system volume is refreshed with the new version of the chosen operating system, the host is configured with the same IP address and hostname, all volumes are re-mounted, and the Ambari agent is installed and configured. After the host has rejoined the cluster, the Ambari Recover Host functionality is used to reinstall, reconfigure, and start services. To ensure that no data is lost during the reinstall of the operating system, verify that your OS volumes do not contain any HDP data or metadata. Additionally, during the OS reinstall, make sure that you do not erase or reformat any non-operating-system volumes, such as HDFS data drives, as this may result in data loss.