Hello Fernando,
In this case, you could build your own image once, install the plugin during the build (when you do have root privileges), and deploy that image in EKS.
FROM wazuh/wazuh-indexer:4.13.1
USER root
RUN /usr/share/wazuh-indexer/bin/opensearch-plugin install --batch repository-s3
USER 1000
Then build and push it to your private registry (ECR, for example):
docker build -t <your-ecr-repo>:wazuh-indexer-s3 .
docker push <your-ecr-repo>:wazuh-indexer-s3
Then modify your Wazuh Helm values or Deployment manifest to use this image:
image:
repository: <your-ecr-repo>
tag: wazuh-indexer-s3
Let me know if this works for you.