Agent will not stay up - WARNING: got signal 33

Products

• Workload Automation Agent
• ESP dSeries Workload Automation - System Agent (dSeries)
• ESP dSeries Workload Automation - Business Agents (dSeries)

Issue/Introduction

User is experiencing a reoccurring issue where agent service keeps shutting down.

Symptoms:

• The WA Agent stops running unexpectedly.
• Jobs submitted to the affected Agent may fail or go into UNKNOWN status.
• The cybagent_service log file shows messages indicating a "Signal 33".

Error Message:

The cybagent_service log file contains entries similar to:

11/03/2025 09:15:34.288EST: WARNING: got signal 33
11/03/2025 09:15:34.301EST: Couldn't wait for JVM process: A system call received an interrupt.

11/03/2025 09:15:34.301EST: CybAgentDriver has exited

 

Environment

• Workload Automation Agent
• Operating System: AIX

Cause

This issue occurs on AIX when the system experiences virtual memory exhaustion (a combination of physical memory/RAM and paging space).

AIX actively monitors its free paging space blocks. When it detects that the paging space is critically low, it issues "Signal 33" (SIGDANGER) to all active processes as an initial warning. This signal indicates that the system is running out of vital memory resources.

If the low memory condition persists, AIX will begin terminating processes to reclaim resources. The CybAgentDriver has exited message, preceded by Signal 33, indicates that the AIX operating system has terminated the Agent process due to insufficient system resources, specifically a lack of available paging space. The root cause is an insufficient paging space configuration on the AIX server.

Resolution

1. Engage your AIX System Administrator to investigate and address the system's virtual memory and paging space configuration.
2. Increase the paging space on the affected AIX system. The appropriate size for paging space depends on the server's RAM and workload; your AIX administrator will be able to determine the optimal configuration.
3. Monitor system resources (RAM, paging space utilization) on the AIX server to ensure sufficient capacity for all running applications, including the WA Agent.

Additional Information

• Signal 33 (SIGDANGER) is an AIX-specific signal that warns processes about impending system-wide resource depletion, particularly critical paging space. It is a preemptive measure by the OS to prevent a full system crash.
• While the Agent logs indicate an exit, the underlying cause is an OS-level resource constraint, not typically an Agent application fault itself.
• Reviewing AIX system logs (e.g., errpt output) during the time of the incident may provide further details on memory exhaustion events.