Running script exporter on Kubernetes

[pawelrys]

Hi, I have a problem with understanding how your script should work on Kubernetes. It could be caused by my small knowledge about the Kubernetes environment, but I hope you could something explain to me. Using it locally isn't a problem, but on Kubernetes, it is.

Suppose I have a cluster named my-cluster and in there a few samples pods which exhibit hello world page. My job is to get data about specific files from the containers on which programs are running, for example, on path ~/var/app/log I have two files: log_1.log and log_2.log (in every container). I would like to calculate how many days is between creating/updating log_1.log and log_2.log, export it to Prometheus and creating a diagram in Grafana about this information in every container.

Should I install the script exporter on every container and exhibit the information about differences in files, or can I create the script exporter as the next pod in my cluster and get access to the filesystem in every container to get the required data? If can I do it in a second way, could you explain how it should look?

Thank you very much in advance for your time.

Paweł

[ricoberger]

Hi @pawelrys, if these logs are only available ~/var/app/log in your application container, then I would recommend to add the script_exporter as sidecar and share the volume with the log files between the two containers, like it is shown here: https://kubernetes.io/docs/tasks/access-application-cluster/communicate-containers-same-pod-shared-volume/.

If these logs are also written to stdout / stderr then you can also run the script_exporter as privileged pod and run your scripts on the host, because these logs should be available at /var/logs/containers on the node where the application pod is running. I think the DaemonSet can then look similar to the following one:

---
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: script-exporter
spec:
  selector:
    matchLabels:
      app: script-exporter
  template:
    metadata:
      labels:
        app: script-exporter
    spec:
      containers:
        - image: ricoberger/script_exporter
          name: script-exporter
          volumeMounts:
            - mountPath: /var/log
              name: varlog
            - name: config
              mountPath: /etc/script_exporter
      volumes:
        - hostPath:
            path: /var/log
          name: varlog
        - name: config
          configMap:
            name: script-exporter
            defaultMode: 0777

It just contains the basic fields to get an idea of it. You may also have to add some other fields from the example Deployment: https://github.com/ricoberger/script_exporter/blob/master/examples/kubernetes.yaml.

[ricoberger]

I would close this issue. If you still have some problems with running the exporter on Kubernetes please let me know.