Known Limitations

This section consists of known limitations we are aware of, persisting in this release.

During the ODP upgrade, where Ambari-2.7.8.0 has already been upgraded, the following services will experience downtime. This downtime will interrupt the ODP stack upgrade when using express or rolling upgrade methods.

Affected Services:

  • Kafka
  • Ranger
  • Ranger KMS

Kafka

After completing the Ambari upgrade, during the rolling or express upgrade, Kafka needs to be up and running in a healthy mode. However, Kafka is in a stopped state due to the following errors:

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These issues occur because Kafka Connect and MirrorMaker were added in this release.

Solution

To start Kafka, add the following configurations in Ambari:

  1. Custom kafka-mirrormaker2-common

    • replication.factor =1
  2. Custom kafka-mirrormaker2-destination

    • replication.enabled=true
    • destination.cluster.name=dest
    • topics.whitelist=.*
  3. Custom kafka-mirrormaker2-source

    • replication.enabled=true
    • source.cluster.name=source
    • topics.whitelist=.*
  4. Custom kafka-connect-distributed

    • bootstrap.servers=localhost:6667

Proceed with restarting the Kafka service. It should start smoothly.

Ranger

During the cluster upgrade (after Ambari is upgraded to 2.7.8.0 but before the ODP stack is upgraded), the Ranger service will not start due to the following errors:

Error
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Error
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Solution

  1. Log in to the backend database for Ambari-server.

    • In this case, MySQL is used as the Ambari-server’s backend database.
  2. Execute the following SQL query to identify the required configurations:

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  1. Expected Response:
Bash
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  1. Update the required configurations:
  • Ranger-admin service: Update admin-log4j to admin-logback
SQL
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  • Ranger tagsync service: Update tagsync-log4j to tagsync-logback
SQL
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  • Ranger usersync service: Update usersync-log4j to usersync-logback
SQL
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  1. Restart the Ambari-server:
Bash
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Proceed with the Ranger service restart from the Ambari UI. It should start smoothly.

Ranger KMS

During the cluster upgrade (after Ambari is upgraded to 2.7.8.0 but before the ODP stack is upgraded), the Ranger-KMS service will not start due to the following error:

Error
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Actually, kms-log4j is replaced with kms-logback starting from version 3.2.3.x.

Solution

Log in to the backend database for the Ambari server.

In this case, MySQL is the backend database for the Ambari server.

SQL
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Response:

response
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Ranger-Admin Service Required Change

Update kms-log4j to kms-logback:

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From the Ambari-Server host, perform the following steps:

  1. Edit the File:

Path: /var/lib/ambari-server/resources/stacks/ODP/3.0/services/RANGER_KMS/package/scripts/kms.py

Locate the following lines:

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Comment them out as shown below:

Python
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  1. Restart the Ambari-Server:
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Proceed with restarting the Ranger-KMS service from the Ambari UI. It should start smoothly.

Update the Ranger Configuration

  1. Log in to the Ambari UI and navigate to RANGERCONFIGS -> ADVANCED -> Advanced admin-logback, update the following content, and save.
Bash
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  1. On the Ambari UI, navigate to RANGERCONFIGS -> ADVANCED -> Advanced tagsync-logback, update with the following content, and save.
Bash
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  1. On the Ambari UI, navigate to RANGERCONFIGS -> ADVANCED -> Advanced usersync-logback, update with the following content, and save.
Bash
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  1. Restart the Ranger service from the Ambari UI.

Update the Ranger KMS Configuration

  1. Log in to the Ambari UI and navigate to RANGERCONFIGS -> ADVANCED -> Advanced admin-logback, update the following content, and save.
Bash
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  1. Restart the Ranger KMS service from the Ambari UI.

Other Known Limitations

Ozone

  • Ozone service check fails when Ranger is enabled.
  • Workaround*: Create a new policy for ambari-qa user to access only ambarismokevolume as an admin.
  • Ozone mpack supports Secure Ozone only on fresh Ozone installations on Kerberized clusters.
  • Ozone 1.4.0 limits Ranger Audit due to open bugs related to performance.
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