1. Prerequisites

To perform an HDP upgrade using Ambari, your cluster must meet the following prerequisites. These prerequisites are required regardless of Rolling or Express upgrade because these checks are important for Ambari to know the cluster is in a healthy operating mode and can be successfully managed from Ambari. However, there are additional prerequisites for a Rolling Upgrade that require your cluster to be configured a certain way to support the rolling upgrade orchestration process.

Check	Description
HDP Version	All hosts must have the target HDP version installed. See the Register and Install Target Version section for more information.
Disk Space	Be sure to have adequate space on `/usr/hdp` for the target HDP version. Each complete install of an HDP version will occupy about 2.5 GB of disk space.
Ambari Agent Heartbeats	All Ambari Agents must be communicating and heartbeating to Ambari Server. Any hosts that are not heartbeating must be in Maintenance Mode.
Host Maintenance Mode	The following two scenarios are checked: Any hosts in Maintenance Mode must not be hosting any Service Master Components. Any host in Maintenance Mode that is not hosting Master Components is allowed but you will receive a warning. You can proceed with your upgrade but these hosts will not be upgraded and before you can finalize the upgrade, you must delete the hosts from the cluster.
Service Maintenance Mode	No Services can be in Maintenance Mode.
Services Started	All Services must be started.
Service Checks	All Service Checks must pass. Be sure to run Service Actions > Run Service Check on all services (and remediate if necessary) prior to attempting an HDP upgrade.

	Important
If your cluster has Kerberos enabled, includes Kafka and you are running HDP 2.2, since Kafka in HDP 2.2 did not support running Kerberized, after upgrade to HDP 2.3 or later (regardless if you perform an Express or Rolling Upgrade), Kafka will then be Kerberos enabled. Plan to adjust your use of Kafka accordingly. Ambari will perform a check to see if your cluster would encounter this issue and warn you prior to performing the HDP upgrade.

Important

If your cluster has Kerberos enabled, includes Kafka and you are running HDP 2.2, since Kafka in HDP 2.2 did not support running Kerberized, after upgrade to HDP 2.3 or later (regardless if you perform an Express or Rolling Upgrade), Kafka will then be Kerberos enabled. Plan to adjust your use of Kafka accordingly. Ambari will perform a check to see if your cluster would encounter this issue and warn you prior to performing the HDP upgrade.

​1. Prerequisites

1. Prerequisites