Running Containers Are Not Healthy Containers

The Docker daemon can report a container as running even when the application inside it has stopped serving useful traffic. On hserver the first signal I use for this question is container state plus Docker healthcheck state. Process liveness and application readiness are different contracts; monitoring only the former creates false green dashboards.

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

The practical control is straightforward: Use healthchecks where the application has a meaningful probe, graph unhealthy counts, and keep external probes for user-visible reachability. 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.