ceph/examples/lua/prometheus_adapter.md

Introduction

This directory contains an example prometheus_adapter.lua on how to use Lua Scripting to push metrics from the RGW requests to Prometheus, specifically to collect information on object sizes.

Prometheus

As every single run of a lua script is short-lived, so Pushgateway should be used as an intermediate service to enable Prometheus to scrape data from RGW.

• Install and run Pushgateway using docker:

docker pull prom/pushgateway
docker run -p 9091:9091 -it prom/pushgateway

• Install and run Prometheus using docker:

docker pull prom/prometheus
docker run --network host -v ${CEPH_DIR}/examples/lua/config/prometheus.yml:/etc/prometheus/prometheus.yml prom/prometheus

Full documentation for Prometheus installation

Usage

• Upload the script:

radosgw-admin script put --infile=prometheus_adapter.lua --context=postRequest

• Add the packages used in the script:

radosgw-admin script-package add --package='luasocket' --allow-compilation

• Restart radosgw.

• Send a request:

s3cmd --host=localhost:8000 --host-bucket="localhost:8000/%(bucket)" --access_key=0555b35654ad1656d804 --secret_key=h7GhxuBLTrlhVUyxSPUKUV8r/2EI4ngqJxD7iBdBYLhwluN30JaT3Q== mb s3://mybucket
s3cmd --host=localhost:8000 --host-bucket="localhost:8000/%(bucket)" --access_key=0555b35654ad1656d804 --secret_key=h7GhxuBLTrlhVUyxSPUKUV8r/2EI4ngqJxD7iBdBYLhwluN30JaT3Q== put -P /etc/hosts s3://mybucket
curl http://localhost:8000/mybucket/hosts

• Open http://localhost:9090 by browser and search for rgw_request_content_length

Requirements

• Lua 5.3 or higher