Hello @iceqboy ,   thank you for raising your enquiry about how to upgrade the OS version on a cluster.   As a first step, please upgrade your OS.   [1] points out that temporarily - while the OS upgrade is carried out - it is supported by Cloudera to run on mixed minor version releases. It means that it is less risky to run on different minor OS releases than on different OS-es.   [2] describes that: "Upgrading the operating system to a higher version but within the same major release is called a minor release upgrade. For example, upgrading from Redhat 6.8 to 6.9. This is a relatively simple procedure that involves properly shutting down all the components, performing the operating system upgrade, and then restarting everything in reverse order."   Once the cluster is on the same OS release, the next step is to upgrade your CM [3]. The CM version has to be higher or equal to the CDH version you are upgrading to. Then please follow our documentation on how to upgrade to CDH5.16. [4]   Please let us know if we addressed your enquiry!   Best regards: Ferenc   [1] https://docs.cloudera.com/documentation/enterprise/release-notes/topics/rn_consolidated_pcm.html [2] https://docs.cloudera.com/cdp/latest/upgrade-cdh/topics/ug_os_upgrade.html [3] https://docs.cloudera.com/cdp/latest/upgrade-cdh/topics/ug_cm_upgrade.html [4] https://docs.cloudera.com/cdp/latest/upgrade-cdh/topics/ug_cdh_upgrade.html ... View more