F5CAB5 Exam Dumps : BIG-IP Administration Support and Troubleshooting (F5CAB5) exam

The "Manual Resume" feature is a safety mechanism used when a pool is not working as expected due to flapping services or unstable backend applications. Normally, when a health monitor fails, the pool member is marked "Offline" (Red), and when the monitor passes, it automatically returns to "Available" (Green)47. However, if "Manual Resume" is enabled, the BIG-IP will not automatically put the member back into rotation after a failure48. Even if the health check begins to pass again, the member remains in an "Offline (Disabled)" state49. This requires an administrator to manually intervene and re-enable the member. This is a common point of confusion when troubleshooting; a member may show passing health checks but still not receive traffic because it is waiting for a manual administrative "resume" command. This feature is intended to prevent "unhealthy" servers from receiving traffic until an engineer has confirmed the root cause of the initial failure was resolved.

This log entry indicates that multiple monitors are assigned to the pool member, and the member is failing one of them.

Understanding Monitor Logic: By default, if multiple monitors are assigned to a pool or pool member without a "Minimum To Up" (Availability Requirement) setting, the system requires all monitors to pass for the member to be marked "Up".

Analyzing the Log: The log clearly states: [ /Common/http: up, /Common/http2: down; ... ]. This means the standard HTTP monitor is successful, indicating the member is serving HTTP traffic, but the http2 monitor has failed.

Conclusion: Since the http monitor is "up" but the member as a whole is "down," we can conclude the member is successfully responding to standard HTTP requests but not HTTP2 requests. Therefore, the member is currently only serving standard HTTP traffic.

The key clue in the exhibit is the pool member’s availability showing“Offline (Enabled) – Parent down”. In BIG-IP terminology, a pool member inherits the status of itsparent node. If thenodeis marked down (for example, by a node-level monitor or a default “node is down” condition), thenall pool members using that node IPwill also be marked down and will not receive any traffic, even if the application service on the member port might be healthy.

While the HTTPS monitor configuration (send/receive strings) is displayed, the statusspecificallyindicates anode (parent) failure, not a service-level failure. If the problem were the application not matching the receive string, you would typically see the member down due to themember’s monitorfailing (and the status would reflect monitor failure details), rather than “parent down.”

Option D is too broad; BIG-IP can generally reach the subnet (other servers work), and this symptom points to a specific node condition. Option C is incorrect because HTTP/1.1 is commonly used for monitoring and is valid when properly formatted (especially with a Host header). Therefore, the most likely cause is that thenode health monitor is not responding, causing the node—and consequently the member—to be marked down.