Transport Nginx Access Logs into Kafka with Logging operator

This guide describes how to collect application and container logs in Kubernetes using the Logging operator, and how to send them to Kafka.

The following figure gives you an overview about how the system works. The Logging operator collects the logs from the application, selects which logs to forward to the output, and sends the selected log messages to the output. For more details about the Logging operator, see the Logging operator overview.

Deploy Kafka

This demo uses Koperator to create an Apache Kafka cluster in Kubernetes. For details on installing it, see the Koperator installation guide.

Deploy the Logging operator and a demo Application

Install the Logging operator and a demo application to provide sample log messages.

Deploy the Logging operator with Helm

To install the Logging operator using Helm, complete the following steps.

Note: You need Helm v3.8 or later to be able to install the chart from an OCI registry.

1. Install the Logging operator into the logging namespace:

   helm upgrade --install --wait --create-namespace --namespace logging logging-operator oci://ghcr.io/kube-logging/helm-charts/logging-operator
   

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   Expected output:

   Release "logging-operator" does not exist. Installing it now.
   Pulled: ghcr.io/kube-logging/helm-charts/logging-operator:4.3.0
   Digest: sha256:c2ece861f66a3a2cb9788e7ca39a267898bb5629dc98429daa8f88d7acf76840
   NAME: logging-operator
   LAST DEPLOYED: Wed Aug  9 11:02:12 2023
   NAMESPACE: logging
   STATUS: deployed
   REVISION: 1
   TEST SUITE: None
   

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   Note:

   • Helm has a known issue in version 3.13.0 that requires users to log in to the registry, even though the repo is public.

     Upgrade to 3.13.1 or higher to avoid having to log in, see: https://github.com/kube-logging/logging-operator/issues/1522

   • If you’re installing the Helm chart from Terraform, reference the repository as repository = "oci://ghcr.io/kube-logging/helm-charts/" (without the logging-operator suffix). Otherwise, you’ll get a 403 Forbidden error.

2. Validate your deployment.

3. Create the logging resource.

   kubectl -n logging apply -f - <<"EOF"
   apiVersion: logging.banzaicloud.io/v1beta1
   kind: Logging
   metadata:
     name: default-logging-simple
   spec:
     fluentd: {}
     fluentbit: {}
     controlNamespace: logging
   EOF
   

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   Note: You can use the ClusterOutput and ClusterFlow resources only in the controlNamespace.

4. Create a Kafka output definition.

   kubectl -n logging apply -f - <<"EOF"
   apiVersion: logging.banzaicloud.io/v1beta1
   kind: Output
   metadata:
    name: kafka-output
   spec:
    kafka:
      brokers: kafka-headless.kafka.svc.cluster.local:29092
      default_topic: topic
      format:
        type: json
      buffer:
        tags: topic
        timekey: 1m
        timekey_wait: 30s
        timekey_use_utc: true
   EOF
   

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   Note: In production environment, use a longer timekey interval to avoid generating too many objects.

5. Create a flow resource.

   kubectl -n logging apply -f - <<"EOF"
   apiVersion: logging.banzaicloud.io/v1beta1
   kind: Flow
   metadata:
     name: kafka-flow
   spec:
     filters:
       - tag_normaliser: {}
       - parser:
           remove_key_name_field: true
           reserve_data: true
           parse:
             type: nginx
     match:
       - select:
           labels:
             app.kubernetes.io/name: log-generator
     localOutputRefs:
       - kafka-output
   EOF
   

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6. Install log-generator to produce logs with the label app.kubernetes.io/name: log-generator

   helm upgrade --install --wait --create-namespace --namespace logging log-generator oci://ghcr.io/kube-logging/helm-charts/log-generator
   

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7. Validate your deployment.

Validate the deployment

Run the following command to consume some log messages from Kafka:

kubectl -n kafka run kafka-consumer -it --image=banzaicloud/kafka:2.13-2.4.0 --rm=true --restart=Never -- /opt/kafka/bin/kafka-console-consumer.sh --bootstrap-server kafka-headless:29092 --topic topic --from-beginning

Expected output:

{"stream":"stdout","logtag":"F","kubernetes":{"pod_name":"logging-demo-log-generator-5f9f9cdb9f-z76wr","namespace_name":"logging","pod_id":"a7174256-31bf-4ace-897b-77899873d9ad","labels":{"app.kubernetes.io/instance":"logging-demo","app.kubernetes.io/name":"log-generator","pod-template-hash":"5f9f9cdb9f"},"host":"ip-192-168-3-189.eu-west-2.compute.internal","container_name":"log-generator","docker_id":"7349e6bb2926b8c93cb054a60f171a3f2dd1f6751c07dd389da7f28daf4d70c5","container_hash":"ghcr.io/banzaicloud/log-generator@sha256:814a69be8ab8a67aa6b009d83f6fa6c4776beefbe629a869ff16690fde8ac362","container_image":"ghcr.io/banzaicloud/log-generator:0.3.3"},"remote":"79.104.42.168","host":"-","user":"-","method":"PUT","path":"/products","code":"302","size":"18136","referer":"-","agent":"Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/33.0.1750.166 Safari/537.36 OPR/20.0.1396.73172","http_x_forwarded_for":"-"}
{"stream":"stdout","logtag":"F","kubernetes":{"pod_name":"logging-demo-log-generator-5f9f9cdb9f-mpp98","namespace_name":"logging","pod_id":"e2822c26-961c-4be8-99a2-b17517494ca1","labels":{"app.kubernetes.io/instance":"logging-demo","app.kubernetes.io/name":"log-generator","pod-template-hash":"5f9f9cdb9f"},"host":"ip-192-168-2-102.eu-west-2.compute.internal","container_name":"log-generator","docker_id":"26ffbec769e52e468216fe43a331f4ce5374075f9b2717d9b9ae0a7f0747b3e2","container_hash":"ghcr.io/banzaicloud/log-generator@sha256:814a69be8ab8a67aa6b009d83f6fa6c4776beefbe629a869ff16690fde8ac362","container_image":"ghcr.io/banzaicloud/log-generator:0.3.3"},"remote":"26.220.126.5","host":"-","user":"-","method":"POST","path":"/","code":"200","size":"14370","referer":"-","agent":"Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:52.0) Gecko/20100101 Firefox/52.0","http_x_forwarded_for":"-"}

If you don’t get the expected result you can find help in the troubleshooting section.