Known issues

This section lists known issues that you might run into while using the Data Hub service.

CB-11925: Knox Load Balancer API requests initiated from Knox Gateway hosts can fail with Connection timeout error

Problem: When logged into a Data Lake or Data Hub node that has a Knox Gateway service instance configured on it, making Knox API calls through the Knox load balancer can result in a connection timeout error. This is because for security reasons, the IP address of the request is preserved in the traffic passed through the load balancer. Preserving the IP address means that the load balancer will reject "loopback" traffic, meaning traffic that originates and is directed back to the same node.

Workaround: If Knox API calls need to be made while logged into a Knox gateway node, use the hostname of the node instead of the load balancer hostname in the API call.

The Knox load balancer hostname can be identified by the "-gateway" suffix in the first clause of the hostname with no numeric identifier. For example: <cluster-name>-gateway.<env-shortname>.<hash>.cloudera.site is the load balancer hostname, and <cluster-name>-gateway0.<env-shortname>.<hash>.cloudera.site is a direct node hostname.

Technical Service Bulletins

TSB 2022-568: HBase normalizer must be disabled for Salted Phoenix tables
When Apache Phoenix (“Phoenix”) creates a salted table, it pre-splits the table according to the number of salt regions. These regions must always be kept separate, otherwise Phoenix does not work correctly.

The HBase normalizer is not aware of this requirement, and in some cases the pre-split regions are merged automatically. This causes failure in Phoenix.

The same requirement applies when merging regions of salted tables manually: regions containing different salt keys (the first byte of the rowkey) must never be merged.

Note that either automatic or manual splitting of the regions for a salted table does not cause a problem. The problem only occurs when adjacent regions containing different salt keys are merged.

Upstream JIRA
PHOENIX-4906
Impact
Customers using the salted table feature of Phoenix.
Action required
  • Checking for affected tables:
    1. Run the following query from phoenix-sqlline to find the salted tables:
      select TABLE_SCHEM,TABLE_NAME from system.catalog where salt_buckets>0;
    2. From hbase shell run describe 'SCHEMA.TABLE' for each salted table, substituting the schema and table (for tables without schema, use just the table name) and look for {NORMALIZATION_ENABLED => 'true'} in the output.
  • If normalizer has been enabled on a salted Phoenix table, the HBase normalizer must be disabled manually. From HBase shell, run the following command for each salted Phoenix table:
    alter 'SCHEMA_NAME.TABLE_NAME', {NORMALIZATION_ENABLED => 'false'} 
    (If the table is in the default schema, just use 'TABLE_NAME')
Knowledge article
For the latest update on this issue, see the corresponding Knowledge article: TSB 2022-568: Hbase normalizer must be disabled for Salted Phoenix tables