How to monitor MinIO server with Prometheus Slack

Prometheus is a cloud-native monitoring platform, built originally at SoundCloud. Prometheus offers a multi-dimensional data model with time series data identified by metric name and key/value pairs. The data collection happens via a pull model over HTTP/HTTPS. Targets to pull data from are discovered via service discovery or static configuration.

MinIO exports Prometheus compatible data by default as an authorized endpoint at /minio/prometheus/metrics. Users looking to monitor their MinIO instances can point Prometheus configuration to scrape data from this endpoint.

This document explains how to setup Prometheus and configure it to scrape data from MinIO servers.

Table of Contents

Prerequisites

To get started with MinIO, refer MinIO QuickStart Document. Follow below steps to get started with MinIO monitoring using Prometheus.

1. Download Prometheus

Download the latest release of Prometheus for your platform, then extract it

tar xvfz prometheus-*.tar.gz
cd prometheus-*

Prometheus server is a single binary called prometheus (or prometheus.exe on Microsoft Windows). Run the binary and pass --help flag to see available options

./prometheus --help
usage: prometheus [<flags>]

The Prometheus monitoring server

. . .

Refer Prometheus documentation for more details.

2. Configure authentication type for Prometheus metrics

MinIO supports two authentication modes for Prometheus either jwt or public, by default MinIO runs in jwt mode. To allow public access without authentication for prometheus metrics set environment as follows.

export MINIO_PROMETHEUS_AUTH_TYPE="public"
minio server ~/test

3. Configuring Prometheus

3.1 Authenticated Prometheus config

If MinIO is configured to expose metrics without authentication, you don't need to use mc to generate prometheus config. You can skip reading further and move to 3.2 section.

The Prometheus endpoint in MinIO requires authentication by default. Prometheus supports a bearer token approach to authenticate prometheus scrape requests, override the default Prometheus config with the one generated using mc. To generate a Prometheus config for an alias, use mc as follows mc admin prometheus generate <alias>.

The command will generate the scrape_configs section of the prometheus.yml as follows:

scrape_configs:
- job_name: minio-job
  bearer_token: <secret>
  metrics_path: /minio/prometheus/metrics
  scheme: http
  static_configs:
  - targets: ['localhost:9000']

3.2 Public Prometheus config

If Prometheus endpoint authentication type is set to public. Following prometheus config is sufficient to start scraping metrics data from MinIO.

scrape_configs:
- job_name: minio-job
  metrics_path: /minio/prometheus/metrics
  scheme: http
  static_configs:
  - targets: ['localhost:9000']

4. Update scrape_configs section in prometheus.yml

To authorize every scrape request, copy and paste the generated scrape_configs section in the prometheus.yml and restart the Prometheus service.

5. Start Prometheus

Start (or) Restart Prometheus service by running

./prometheus --config.file=prometheus.yml

Here prometheus.yml is the name of configuration file. You can now see MinIO metrics in Prometheus dashboard. By default Prometheus dashboard is accessible at http://localhost:9090.

List of metrics exposed by MinIO

MinIO server exposes the following metrics on /minio/prometheus/metrics endpoint. All of these can be accessed via Prometheus dashboard. The full list of exposed metrics along with their definition is available in the demo server at https://play.min.io:9000/minio/prometheus/metrics

These are the new set of metrics which will be in effect after RELEASE.2019-10-16*. Some of the key changes in this update are listed below.
- Metrics are bound the respective nodes and is not cluster-wide. Each and every node in a cluster will expose its own metrics.
- Additional metrics to cover the s3 and internode traffic statistics were added.
- Metrics that records the http statistics and latencies are labeled to their respective APIs (putobject,getobject etc).
- Disk usage metrics are distributed and labeled to the respective disk paths.

For more details, please check the Migration guide for the new set of metrics

The list of metrics and its definition are as follows. (NOTE: instance here is one MinIO node)

NOTES:
> 1. Instance here is one MinIO node.
> 2. s3 requests exclude internode requests.

Apart from above metrics, MinIO also exposes below mode specific metrics

Cache specific metrics

MinIO Gateway instances enabled with Disk-Caching expose caching related metrics.

S3 Gateway & Cache specific metrics

MinIO S3 Gateway instance exposes metrics related to Gateway communication with AWS S3.

Migration guide for the new set of metrics

This migration guide applies for older releases or any releases before RELEASE.2019-10-23*

MinIO disk level metrics - disk_*

The migrations include

- `minio_total_disks` to `minio_disks_total`
- `minio_offline_disks` to `minio_disks_offline`

MinIO disk level metrics - disk_storage_*

These metrics have one label.

- `disk`: Holds the disk path

The migrations include

- `minio_disk_storage_used_bytes` to `disk_storage_used`
- `minio_disk_storage_available_bytes` to `disk_storage_available`
- `minio_disk_storage_total_bytes` to `disk_storage_total`

MinIO network level metrics

These metrics are detailed to cover the s3 and internode network statistics.

The migrations include

- `minio_network_sent_bytes_total` to `s3_tx_bytes_total` and `internode_tx_bytes_total`
- `minio_network_received_bytes_total` to `s3_rx_bytes_total` and `internode_rx_bytes_total`

Some of the additional metrics added were

- `s3_requests_total`
- `s3_errors_total`
- `s3_ttfb_seconds`