16. Finalize Upgrade

When you are satisfied that HDP is successfully functioning with the data maintained from the HDP 1.3 or 2.0 cluster, finalize the upgrade.

	Note
	After you have finalized the upgrade, you cannot revert.

Run the following command to open a command prompt with the Hadoop user in the Hadoop Home directory:
```
runas /user:hadoop "cmd /K cd %HADOOP_HOME%\bin"
```

To finalize the upgrade, run the following command:

hadoop dfsadmin -finalizeUpgradeTroubleshooting HDP 2.1 service start