The Stack is the coordinated set of Hadoop components that you have installed. Use the following instructions to upgrade a current, Ambari-installed and managed instance of a 1.3.2 or later version Stack to a 2.1 version Stack. This procedure causes the upgraded stack to be managed by Ambari.
![[Note]](../common/images/admon/note.png) | Note |
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If your stack has Kerberos Security turned on, you should turn it off before performing the upgrade. On Ambari Web > Admin view > Security > click Disable Security. You can re-enable Security after performing the upgrade. |
If you are upgrading from any other 1.x version of the stack, you must upgrade to 1.3.2 or later before you can upgrade to 2.1. See Upgrading the HDP Stack to 1.3.3 for more information. Upgrades from previous 1.x versions are not supported.
