It is recommended to follow the upgrade process by drilling down to the services being upgraded. Especially if it might take long time (one time, the NameNode upgrade got stucked because of the Safemode status – solution is described here).
Now the upgrade can begin. Click on Perform Upgrade
Two upgrade options are available – Rolling Upgrade and Express Upgrade. The Rolling Upgrade keeps the services running, while the Express Upgrade stops the services while the upgrade is performed.
Click on Express Upgrade and click on Proceed.
Confirmation window appears. Select Yes to move on
You are asked to stop all YARN queues. This step can be passed, check the checkbox and click Proceed if you have not made any changes to the property mentioned in the warning window.
Warning about the upgrade being finalized and downgrade is not an option. Check the checkbox if the manual backup steps have been performed.
Click on Finalize.
The upgrade process is running and graphical interfce offers an insight into the process by drilling down to the services being processed. It is possible to see the out and err log files.
If there is an error in during the process, it can be fixed and that particular step can be installed again.
After the upgrade process is finished, a report similar to the one below comes up
Clicking on Dismiss concludes the upgrade process and the current HDP version is now 188.8.131.52-169
If you check Stack and Versions under menu Admin, tab Stack, you will see that all services, installed or uninstalled, have a version number ending with 2.4