The Shoreline CoreDNS Op Pack monitors metrics and automatically triggers an Action that restarts the CoreDNS pod once latency exceeds a configurable threshold. Shoreline can gather CoreDNS metrics as frequently as once per second, using multiple data points and different percentiles when deciding if CoreDNS resolves slowly or not. Shoreline focuses on DNS latency rather than overall measured latency because it helps disambiguate latency from the network versus latency from DNS resolution. This practice prevents false positives when clusters experience high network latency. The Alarm threshold is configured in milliseconds so that you can tightly control the latency tolerance. Once an issue is identified, Shoreline triggers rolling restarts of CoreDNS pods to prevent service outages.
In addition, the CoreDNS Op Pack offers the ability to automatically create a PagerDuty incident or Slack message when an Alarm or Action is triggered. This capability eliminates another manual step by automating the notification process for further root cause analysis.