Collect Fluentd errors

This section describes how to collect Fluentd error messages (messages that are sent to the @ERROR label from another plugin in Fluentd).

Note: It depends on the specific plugin implementation what messages are sent to the @ERROR label. For example, a parsing plugin that fails to parse a line could send that line to the @ERROR label.

Prerequisites

Configuring readiness probes requires Logging operator 3.14.0 or newer installed on the cluster.

Configure error output

To collect the error messages of Fluentd, complete the following steps.

1. Create a ClusterOutput that receives logs from every logging flow where error happens. For example, create a file output. For details on creating outputs, see Output and ClusterOutput.

   apiVersion: logging.banzaicloud.io/v1beta1
   kind: ClusterOutput
   metadata:
     name: error-file
     namespace: default
       spec:
         file:
           path: /tmp/error.log
   

2. Set the errorOutputRef in the Logging resource to your preferred ClusterOutput.

   apiVersion: logging.banzaicloud.io/v1beta1
   kind: Logging
   metadata:
     name: example
   spec:
     controlNamespace: default
     enableRecreateWorkloadOnImmutableFieldChange: true
     errorOutputRef: error-file
     fluentbit:
       bufferStorage: {}
       bufferStorageVolume:
         hostPath:
           path: ""
       filterKubernetes: {}
   # rest of the resource is omitted
   

   You cannot apply filters for this specific error flow.

3. Apply the ClusterOutput and Logging to your cluster.