Fluentbit Installed in VKS Cluster Reports Blank Entries in VCF Operations

Products

• VMware vSphere Kubernetes Service
• VCF Operations
• VCF Operations/Automation (formerly VMware Aria Suite)

Issue/Introduction

After installing fluentbit package into a VKS cluster for VCF Operations monitoring, there are millions of blank, empty events in VCF Operations.

Fluentbit has been set up with the steps and sample YAML from the vSphere Supervisor Techdocs below:

• Install Fluent Bit
• Fluent Bit Package Reference

 

When viewing fluentbit pod logs in the VKS workload cluster, the following errors are present:

The fluentbit IP and port are the same values configured in the fluent-bit-data-values.yaml

kubectl get pods -n tkg-system

kubectl logs -n tkg-system <fluent-bit pod>

YYYY-MM-DDTHH:MM:SS.ssssssZ stderr F [2025/11/09 08:54:26] [error] [net] TCP connection failed: <fluentbit IP>:<port> (No route to host)
YYYY-MM-DDTHH:MM:SS.ssssssZ stderr F [2025/11/09 08:54:26] [error] [output:syslog:syslog.0] no upstream connections available
YYYY-MM-DDTHH:MM:SS.ssssssZ stderr F [2025/11/09 08:54:29] [error] [upstream] connection #47 to tcp://<fluentbit IP>:<port> timed out after 10 seconds (connection timeout)

Environment

VCF Operations 9 or higher

vSphere Supervisor

Resolution

Ensure that the correct IP and port is configured in the fluent-bit-data-values.yaml.

The outputs section must have a properly set Host and Port for VCF Operations and Log Insight according to the desired Connection Type:

Values in brackets <> should be replaced according to your configuration needs and environment.

 outputs: |
      [OUTPUT]
        Name          <connection type>
        Match         *
        Host          <fluentbit IP>
        Port          <fluentbit port>
        URI           api/v2/events
        Format        json
        tls           <on/off>
        tls.debug     4
        tls.verify    off
        json_date_key timestamp

 

See the below table for Ports organized by Connection Type:

Connection Type	Port	Protocol
syslog	514	UDP
syslog	6514	TCP
http	9000
https	9543
tls on	9543

 

If the fluent-bit-data-values.yaml needs to be updated:

1. Push the YAML changes to the existing fluentbit pods:
   

   vcf packages installed list -A
   
   vcf packages installed update -n <fluentbit package namespace> <fluentbit package name> --values-file <fluent-bit-data-values.yaml>

   
   
   
2. Restart the fluentbit pods to pick up the changes:
   

   kubectl get pods -A | grep fluentbit
   
   kubectl rollout restart daemonset fluentbit -n <fluentbit namespace>

 

If there are concerns that there are networking issues, you can create a custom, simple pod with curl in the same node as a fluentbit pod and confirm that the fluentbit IP can be reached.

Once the custom, simple pod with curl is created and running in the workload cluster node, the below command can be used to curl the fluentbit IP and port above:

kubectl exec -it -n <custom pod namespace> <custom pod name> -- curl -vk <fluentbit IP>:<fluentbit port>