Limitations

Know the limitations and known issues while scaling an HBase REST server.

The number of gateway nodes cannot be modified after the database is created, so plan the number of requested gateway nodes based on the estimated load.
You can scale the HBase REST servers in COD clusters deployed in Amazon Web Services (AWS) environments.
The network address translation (NAT) could interfere with traffic distribution because the current setup relies on a Network Load Balancer for sticky sessions, which may cause all requests to route to a single Knox server. Future COD versions plan to use an Application Load Balancer for more effective distribution based on session cookies. Until then, NAT must be avoided if more than one Knox or REST server is in use.
Knox nodes must be specified at the time of cluster creation, as scaling Knox nodes after deployment is currently not supported.
A Multi-AZ setup can increase data transfer costs, as data might need to pass through multiple services, such as Knox, REST, and HBase region servers across different availability zones before reaching the client.
HBase Client Tarball downloads might fail if Knox re-routes the request to the wrong gateway.
The MICRO scale type does not support multiple Knox instances and scaling of HBase REST servers.
Changing the Knox Provider Configurations and Descriptors using the Knox Admin UI only changes the provider configurations, descriptors, and the generated topologies of the Knox instance whose Admin UI is used.

Known issues

LB based client configs and tarball URLs in the describe-client-connectivity command output fails intermittently: Due to a known Cloudbreak issue, CB-26030, downloading an HBase client configuration intermittently fails when using multiple Gateway nodes.; Retry the download operation until it succeeds.
describe-database command returns incorrect output.: After creating the COD cluster with the required number of gateway and REST worker nodes, when you run the describe-database command, the output always shows 0 number of gateway and REST worker nodes.; Upgrade to the latest COD version.
Rolling operating system upgrade does not function correctly: When you try to perform a rolling upgrade on the COD cluster, it does not work with multiple gateway and REST worker nodes.; Upgrade to the latest COD version.