Docker Daemon Error Bursts Need a Separate Alert

Individual container logs can all look normal while the Docker daemon is failing image, network, storage or runtime operations underneath them. On hserver the first signal I use for this question is Docker daemon warning/error count over time. Daemon-level failures affect the control plane for every container and deserve their own signal rather than being mixed into application logs.

The important part is interpretation rather than collecting another graph. platform-layer log monitoring. That gives the metric a specific operational job instead of making it another number on a dashboard.

The practical control is straightforward: Count daemon errors, retain detailed journal queries, and correlate bursts with container restarts, network failures and deployment activity. This also gives me a repeatable check after deployments, exporter changes, or capacity tuning.

Repository evidence for this monitoring behavior is commit b65d5d4. I keep that reference with the note because a monitoring conclusion is stronger when the configuration and runtime decision that produced it can be inspected later.