When upgrading from 2.1.3 to 2.1.6, the Graphite metrics reporter stops working. The usual startup is logged, and one batch of samples is sent, but the reporting interval comes and goes, and no other samples are ever sent. The logs are free from errors.
Frustratingly, metrics reporting works in our smaller (staging) environment on 2.1.6; We are able to reproduce this on all 6 of production nodes, but not on a 3 node (otherwise identical) staging cluster (maybe it takes a certain level of concurrency?).
Attached is a thread dump, and our metrics.yaml.