Performing a Rolling Upgrade
About This Task
You can use a Rolling Upgrade to upgrade a cluster while preserving cluster operations and minimizing service impact. A Rolling Upgrade takes longer to complete an Express Upgrade. You can perform a rolling upgrade from any HDF 3.0.x release. However, Rolling Downgrade is not supported.
![[Note]](../common/images/admon/note.png) | Note |
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Rolling Upgrade is not supported for NiFi. During the Rolling Upgrade, each NiFi instance is stopped, upgraded, and restarted. |
Before You Begin
You have disabled Auto Start. To do so, go to Admin | Service Auto Start, disable the Auto Start option, and click Save.
You have backed up your SAM and Schema Registry databases
| Note |
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You cannot edit any SAM applications or schemas managed by Schema Registry while the rolling upgrade is in progress. |
Steps
From Admin | Stack and Versions | Versions, click Upgrade.
In the Upgrade Options pop-up window, click Rolling Upgrade, and specify if you would like customized upgrade failure tolerance.
Review any service Checks by clicking the Checks link from the Rolling Upgrade option.
Note You may encounter a
Storm Downtime During Upgradewarning. This message displays in error and it is safe to proceed.Click Proceed and confirm that you want to proceed.
The Rolling Upgrade takes some time to proceed. Monitor the progress in the Upgrade in Progress status bar.
When the Rolling Upgrade stages complete, you may choose to Finalize the upgrade, to Finalize Later or to Downgrade. Finalizing later gives you a chance to perform more validation on the cluster. Downgrade moves the cluster version back to the previous version (basically: reverses the upgrade process stages). Once finalized, you cannot downgrade back to the previous version.
Note If you choose to finalize later, both versions will be listed on the Stack and Versions tab with the starting version displaying as Current. It is not until you finalize that Ambari makes the target version the current version. Also, until you finalize, you will not be able to perform operational changes to the cluster (such as move components, change configurations, etc).