HPA Portal sections Data collection Data collection session monitor

The Data collection session monitor is an additional Java process running on each host where other HPA agents are running.

Its main objective is to manage the Calypso monitoring script (embedded in HPA) running those commands:

  • lscpu - information about the CPU configuration
  • vmstat - information about memory, system processes, paging, interrupts, block I/O, disk, and CPU scheduling
  • ps – information about running processes – calypso focus + all processes
  • netstat – information about protocol and network connections
  • jcmd – JVM diagnostic information
  • jstat – JVM performance information
  • jmap – JVM memory-related information
  • jstack – JVM threads-related information

Resources consumed by this process are very limited:

  • CPU %age negligible
  • RAM - 300 Mb max
  • but underlying commands played by the script can be higher

Automatic start and stop

The monitor process lifecycle is managed automatically by HPA.

  • Automatic start: when an environment is up (at least one DataServer agent is connected in the environment) and no monitor is already running on the host, a monitor process is started automatically.
  • Automatic stop: when an environment goes down (no DataServer agent connected in the environment), all monitors for that environment are stopped automatically.

No manual intervention is required under normal circumstances.

Activate or deactivate per host

The monitor can be enabled or disabled on a per-host basis from the Agents settings screen, under the Data collection sessions monitors section.

  • When set to enabled (the default), the monitor is started automatically on that host
  • When set to disabled, the monitor is stopped and will not be restarted automatically

This is useful to temporarily or permanently disable monitoring on a specific host without affecting other hosts in the same environment.

HpaDebugSessionStarterService flag

Among the agent settings listed in the Agents settings screen, the HpaDebugSessionStarterService flag deserves special attention.

It controls which agents are authorized to launch the monitor process on a given host.

When HPA needs to start a monitor on a host, it asks the agents on that host to spawn the monitor process. Only agents where HpaDebugSessionStarterService is enabled can do so.

At least one agent per host must have this flag enabled for the automatic monitor start to work.