How to send logs to a PersistentVolume? (Rancher Logging Chart, File Output, PVC)

[loic-brtd]

Hi, I'm using the rancher-logging Chart via the Rancher Logging plugin. I'd like to create a File Output to store logs into a volume. This might look something like this :

apiVersion: logging.banzaicloud.io/v1beta1
kind: Output
metadata:
  name: logs-file.output
  namespace: ns
spec:
  file:
    buffer:
      chunk_limit_size: 16MB
      flush_at_shutdown: true
      flush_interval: 5s
      flush_mode: interval
      flush_thread_count: 8
      overflow_action: drop_oldest_chunk
      retry_max_interval: 30s
      retry_timeout: 1h
      retry_type: exponential_backoff
    path: /var/nfs/logs/

But I don't know in which filesystem the logs are stored. Ideally, I'd like to store them inside an existing PersistentVolume, using a PVC (PersistentVolumeClaim) but I don't know how/where to configure this. Could you help me please?

[pepov]

With the logging operator you would configure this in either the Logging resource (spec.fluentd) or the FluentdConfig resource.

Here is an example:
#1304

Let me know if this doesn't answer your question!

[loic-brtd]

Thank you for your quick response!

I think I shouldn't edit the Logging resource manually since it is managed by HELM (and If I use the FluentdConfig resource I would also need to modify the Logging resource). So I'd prefer to be able to configure this though HELM chart values.

Also, I just figured out that I'm not using the chart from this repo but the one from rancher's repo (which I installed from Rancher UI) and it has different configuration values.

If you happen to know how to configure this using rancher's chart it would be great, otherwise I can ask on Rancher's forum instead 😄

[pepov]

I beleive you simply need to configure the fluentd key on the top level here: https://github.com/rancher/charts/blob/dev-v2.10/charts/rancher-logging/102.0.3%2Bup3.17.10/values.yaml#L201

[loic-brtd]

That's what I thought too, but the chart doesn't allow the fluentd.extraVolumes property to be passed through values. I think I'm gonna submit a pull request to add it somewhere here. Thanks again for you help!