c.n.s.igor.jenkins.JenkinsBuildMonitor : Number of items (3205) to cache exceeds upper threshold (1000) in monitor=JenkinsBuildMonitor partition=jenkins-master-prod-xxx

Jenkins has an upper limit on the number of jobs it can cache. If that is exceeded, it will cause triggers to stop working.

Increase the threshold in Igor-local.yml

spinnaker:

  build:

    pollInterval: 60  # in seconds for all monitors

    pollingSafeguard:

       itemUpperThreshold: 10000. 

The metric pollingMonitor.itemsOverThreshold can be used to alert if that limit is exceeded for taking a proactive corrective approach.