Sending Amazon EKS Logs to AWS OpenSearch Using Fluent-Bit

Introduction

Amazon Elastic Kubernetes Service (EKS) generates logs that provide valuable insights into cluster health, application performance, and security. Sending these logs to AWS OpenSearch Service (formerly Elasticsearch) enables real-time monitoring and analysis. This guide outlines the step-by-step process to configure Fluent-Bit for efficient log forwarding from Amazon EKS to AWS OpenSearch.

Prerequisites

Before setting up Fluent-Bit, ensure the following:

• An active AWS account with Amazon EKS and AWS OpenSearch Service configured.

• A running EKS cluster.

• The Kubernetes command-line tool (kubectl) installed and configured.

• AWS CLI installed and authenticated.

Step 1: Deploy Fluent-Bit on Amazon EKS

Fluent-Bit is a lightweight and highly efficient log processor that helps forward logs from Amazon EKS to AWS OpenSearch.

1. Create a Kubernetes namespace for logging:

kubectl create namespace logging

2. Create a Fluent-Bit ConfigMap:

apiVersion: v1

kind: ConfigMap

metadata:

  name: fluent-bit-config

  namespace: logging

data:

  fluent-bit.conf: |

    [SERVICE]

        Flush         5

        Log_Level     info

    

    [INPUT]

        Name         tail

        Path         /var/log/containers/*.log

        Parser       docker

        Tag         kube.*

    [OUTPUT]

        Name        opensearch

        Match       *

        Host        <opensearch-domain>

        Port        443

        TLS         On

        AWS_Auth    On

       Region      <aws-region>

3. Apply this configuration:

kubectl apply -f fluent-bit-config.yaml

4. Deploy Fluent-Bit as a DaemonSet:

apiVersion: apps/v1

kind: DaemonSet

metadata:

  name: fluent-bit

  namespace: logging

spec:

  selector:

    matchLabels:

      name: fluent-bit

  template:

    metadata:

      labels:

        name: fluent-bit

    spec:

      serviceAccountName: fluent-bit

      containers:

      - name: fluent-bit

        image: fluent/fluent-bit:latest

        volumeMounts:

        - name: varlog

          mountPath: /var/log

        - name: config-volume

          mountPath: /fluent-bit/etc

      volumes:

      - name: varlog

        hostPath:

          path: /var/log

      - name: config-volume

        configMap:

         name: fluent-bit-config

5. Apply the DaemonSet configuration:

Kubectl apply -f fluent-bit-daemonset.yaml

Step 2: Grant Fluent-Bit IAM Permissions

To allow Fluent-Bit to send logs securely to AWS OpenSearch, attach the necessary IAM permissions.

1. Create an IAM policy:

aws iam create-policy --policy-name FluentBitOpenSearchPolicy --policy-document file://fluent-bit-policy.json

2. Attach the policy to a new IAM role:

aws iam create-role --role-name FluentBitRole --assume-role-policy-document file://trust-policy.json

aws iam attach-role-policy --role-name FluentBitRole --policy-arn arn:aws:iam::<account-id>:policy/FluentBitOpenSearchPolicy

3. Annotate the Kubernetes service account to use this IAM role:

kubectl annotate serviceaccount fluent-bit -n logging eks.amazonaws.com/role-arn=arn:aws:iam::<account-id>:role/FluentBitRole

Step 3: Verify Logs in AWS OpenSearch

Once Fluent-Bit is running, logs should begin streaming into AWS OpenSearch. To verify:

1. Log into the AWS Management Console.

2. Navigate to AWS OpenSearch Service.

3. Open Kibana and search for logs using:

{ "query": { "match_all": {} } }

Conclusion

By following these steps, Amazon EKS logs can be efficiently collected and stored in AWS OpenSearch using Fluent-Bit. This setup enhances observability, enabling proactive troubleshooting and real-time analysis of Kubernetes workloads.

https://businesscompassllc.com/sending-amazon-eks-logs-to-aws-opensearch-using-fluent-bit/