Managing Cluster Resources
How VectorH Interacts with YARN
VectorH interacts with YARN through a custom implementation of the YARN Client API, named DbAgent.
The DbAgent allocates the amount of resources required by VectorH (memory and cores per container) in a YARN environment. It then starts the set of VectorH backend processes with specific slave nodes given as a list of parameters.
During startup, the required set of cluster resources is registered and resource amounts are computed based on the vectorwise.conf file. If YARN is not present, the Vector Server starts without the DbAgent.
Errors and warnings are logged to the following files:
• vector-agent.log
• vector-wset-appmaster.log
• vector-workload-appmaster.log (if preemption support is enabled)
Note: Typically (although it depends on total resources) you can work on only one database if YARN is enabled, because the DbAgent allocates 75% of the operating system resources to the first X100 server. If an attempt is made to create or connect to another database, the X100 process stops running and returns the warning message, "Not enough memory," in the vector-agent.log file.