Docker high CPU usage
Docker containers add a thin layer of overhead, but high CPU usually comes from the application inside the container, not Docker itself.
Common symptoms
- dockerd or containerd uses noticeable CPU
- Container workloads slow down
- Host CPU spikes during container operations
Likely causes
- Application workload inside containers
- Too many containers on one host
- Overlay filesystem overhead
- Logging or health check overhead
Evidence to look for
Container-level CPU metrics show hot containers
dockerd CPU rises during builds or pulls
Host-level IO rises during container activity
What it usually means
Most Docker CPU issues are really application issues inside containers. True Docker overhead is rare but possible during image operations.
What to do next
- 1Profile the application inside the hot container
- 2Check container CPU limits and host capacity
- 3Reduce logging verbosity and health check frequency
See what's causing your CPU
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