Adding upstream version 18.2.2.upstream/18.2.2

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 59 insertions, 0 deletions

diff --git a/examples/rgw/lua/prometheus_adapter.md b/examples/rgw/lua/prometheus_adapter.md
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+# Introduction
+
+This directory contains an example `prometheus_adapter.lua` on how to
+use [Lua Scripting](https://docs.ceph.com/en/latest/radosgw/lua-scripting/)
+to push metrics from the RGW requests to [Prometheus](https://prometheus.io/), 
+specifically to collect information on object sizes.
+
+## Prometheus
+
+As every single run of a lua script is short-lived,
+so [Pushgateway](https://github.com/prometheus/pushgateway)
+should be used as an intermediate service to enable Prometheus to scrape data
+from RGW.
+
+* Install and run Pushgateway using docker:
+
+```bash
+docker pull prom/pushgateway
+docker run -p 9091:9091 -it prom/pushgateway
+```
+
+* Install and run Prometheus using docker:
+
+```bash
+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](https://prometheus.io/docs/prometheus/latest/installation/)
+
+## Usage
+
+* Upload the script:
+
+```bash
+radosgw-admin script put --infile=prometheus_adapter.lua --context=postRequest
+```
+
+* Add the packages used in the script:
+
+```bash
+radosgw-admin script-package add --package='luasocket' --allow-compilation
+```
+
+* Restart radosgw.
+
+* Send a request:
+```bash
+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`
+![](img/prometheus.png)
+
+## Requirements
+* Lua 5.3 or higher
+