slimtoolkit/slim · error

slim: error => no network info

Error message

slim: error => no network info

What it means

During container inspection in docker-slim's container inspector, the Docker Engine's inspect response came back without a NetworkSettings object. docker-slim requires network metadata to wire probes and expose ports, so it aborts rather than proceed with incomplete container info. This indicates an anomalous or stale inspect result rather than a normal user error.

Source

Thrown at pkg/app/master/inspectors/container/container_inspector.go:747

			logger.Fatalf("[SIGMON] received SIGINT, killing container %s", i.ContainerID)
		case <-i.dockerEventStopCh:
			logger.Debug("[SIGMON] Docker event monitor stopped")
			//not killing target because we are going through a graceful shutdown
			//where we sent the StopMonitor and ShutdownSensor ipc commands
		}
	}()

	if err := i.APIClient.StartContainer(i.ContainerID, nil); err != nil {
		return err
	}

	inspectContainerOpts := dockerapi.InspectContainerOptions{ID: i.ContainerID, Size: true}
	if i.ContainerInfo, err = i.APIClient.InspectContainerWithOptions(inspectContainerOpts); err != nil {
		return err
	}

	if i.ContainerInfo.NetworkSettings == nil {
		return fmt.Errorf("slim: error => no network info")
	}

	if hCfg := i.ContainerInfo.HostConfig; hCfg != nil && !i.isHostNetworked() {
		logger.Debugf("container HostConfig.NetworkMode => %s len(ports)=%d",
			hCfg.NetworkMode, len(i.ContainerInfo.NetworkSettings.Ports))

		if len(i.ContainerInfo.NetworkSettings.Ports) < len(commsExposedPorts) {
			return fmt.Errorf("slim: error => missing comms ports")
		}
	}

	logger.Debugf("container NetworkSettings.Ports => %#v", i.ContainerInfo.NetworkSettings.Ports)

	i.setAvailablePorts(hostProbePorts)

	if i.PrintState {
		i.xc.Out.Info("container",
			ovars{

View on GitHub (pinned to 81940d17fa)

Solutions

1. Verify the container exists and was not removed mid-run: docker inspect <container-id>.
2. Update Docker Engine and docker-slim to matched, current versions.
3. Re-run the slim command; if it recurs, capture daemon logs and file an issue.
4. Ensure the Docker API client/server version negotiation is not pinning an incompatible API version.

Example fix

// before: proceeding blindly
info, _ := client.InspectContainerWithOptions(opts)
use(info.NetworkSettings.Ports)
// after: guard like the inspector does
info, err := client.InspectContainerWithOptions(opts)
if err != nil { return err }
if info.NetworkSettings == nil {
    return fmt.Errorf("slim: error => no network info")
}

info, err := client.InspectContainerWithOptions(opts)
if err == nil && info.NetworkSettings == nil {
    // inspect the container again / verify it exists before proceeding
    _, err = client.InspectContainerWithOptions(opts)
}

func hasNetworkSettings(info *dockertypes.ContainerJSON) bool {
    return info != nil && info.NetworkSettings != nil
}

if err := runSlimContainer(...); err != nil {
    if strings.Contains(err.Error(), "no network info") {
        // re-check container exists, then retry once
        return retryOrInspectManually(containerID)
    }
    return err
}

When it happens

Trigger: Calling RunContainer when the Docker API InspectContainerWithOptions succeeds but returns a ContainerInfo whose NetworkSettings field is nil — e.g. inspecting a container that was just removed, a daemon returning a degraded response, or an unexpected API version quirk.

Common situations: Running slim against a container that was concurrently deleted by another process; very old or very new Docker API versions changing response shape; resource pressure on the daemon producing partial inspect payloads.

Related errors

• slim: error => missing comms ports
• invalid context directory
• no service image
• start monitor timeout
• no docker info

AI-assisted analysis of slimtoolkit/slim@81940d17fa (2026-08-31). Data as JSON: /api/errors/6187783bfd663352. Report an issue: GitHub.