Bug ID 1046785: Missing GTM probes when max synchronous probes are exceeded.

Last Modified: Nov 30, 2022

Affected Product(s):
BIG-IP DNS, GTM(all modules)

Known Affected Versions:
13.1.0, 13.1.0.1, 13.1.0.2, 13.1.0.3, 13.1.0.4, 13.1.0.5, 13.1.0.6, 13.1.0.7, 13.1.0.8, 13.1.1, 13.1.1.2, 13.1.1.3, 13.1.1.4, 13.1.1.5, 13.1.3, 13.1.3.1, 13.1.3.2, 13.1.3.3, 13.1.3.4, 13.1.3.5, 13.1.3.6, 13.1.4, 13.1.4.1, 14.1.0, 14.1.0.1, 14.1.0.2, 14.1.0.3, 14.1.0.5, 14.1.0.6, 14.1.2, 14.1.2.1, 14.1.2.2, 14.1.2.3, 14.1.2.4, 14.1.2.5, 14.1.2.6, 14.1.2.7, 14.1.2.8, 14.1.3, 14.1.3.1, 14.1.4, 14.1.4.1, 14.1.4.2, 14.1.4.3, 14.1.4.4, 14.1.4.5, 14.1.4.6, 15.1.0, 15.1.0.1, 15.1.0.2, 15.1.0.3, 15.1.0.4, 15.1.0.5, 15.1.1, 15.1.2, 15.1.2.1, 15.1.3, 15.1.3.1, 15.1.4, 15.1.4.1, 15.1.5, 16.0.0, 16.0.0.1, 16.0.1, 16.0.1.1, 16.0.1.2, 16.1.0, 16.1.1, 16.1.2, 16.1.2.1

Fixed In:
17.0.0, 16.1.2.2, 15.1.5.1, 14.1.5, 13.1.5

Opened: Sep 15, 2021

Severity: 3-Major

Symptoms

GTM probes are missing, resources are marked down. When instances fail and BIG-IP is not aware of the failure, some virtual servers/pool members are marked as available and some objects are marked down on part of the sync group members. In the /var/log/gtm file, the following message may be seen: 011ae116:4: The list processing time (x seconds) exceeded the interval value. There may be too many monitor instances configured with a y second interval Note that this message is only logged once when gtmd is restarted, or when monitors are added or removed in the gtm configuration.

Impact

-- Resources are marked down. -- Inconsistent monitor statuses across BIG-IP DNS systems in a single sync group, with some showing 'big3d: timed out' and others potentially showing a stale up or down status for the same targets. -- Because some monitor instances don't have monitor traffic, if an instance fails, the BIG-IP DNS systems may not be aware of the failure.

Conditions

Max synchronous probes are exceeded. This value is controlled by the GTM global variable max-synchronous-monitor-requests.

Workaround

Increase the value of Max Synchronous Monitor Requests: tmsh modify gtm global-settings metrics max-synchronous-monitor-requests value <value - default is 20>

Fix Information

All monitors are now allowed to probe without triggering a failure.

Behavior Change

Guides & references

K10134038: F5 Bug Tracker Filter Names and Tips