Lab: Monolithic Mimir with MinIO, Prometheus and Grafana

What you will learn in this TP

• Configure Mimir with object storage
• Connect Prometheus via remote_write
• Query Mimir from Grafana

Introduction #

What you will learn in this section

• Configure Mimir with object storage
• Connect Prometheus via remote_write
• Query Mimir from Grafana

Context. Your team wants to centralise the metrics from several Prometheus servers and keep them for a year. Before sizing a cluster, you build a complete prototype on your workstation.

Prerequisites: Docker Compose, basic knowledge of Prometheus and PromQL  ·  Estimated time: 45 min

A first remote_write → Mimir → Grafana pipeline.

Setup #

Guided steps, with their solutions.

1. 1. Write mimir.yaml

   Why? Mimir needs to know where to store blocks, rules and the alerting configuration; in monolithic mode with a single process, the replication factor must be lowered to 1.

   Write the Mimir configuration: S3 storage pointing to MinIO, three separate buckets, multi-tenancy disabled and replication set to 1.

2. 2. Connect Prometheus

   Why? Prometheus keeps its role as the collector; Mimir is the one that stores and serves the history.

   Write a prometheus.yml that scrapes Prometheus itself and Mimir (mimir:8080), with an external label cluster and a remote_write to Mimir.

3. 3. Start the stack

   Why? A reproducible Compose file lets you restart the lab from scratch at any time.

   Write the docker-compose.yml (MinIO, Mimir, Prometheus, Grafana), start it and wait until Mimir is ready.

4. 4. Check ingestion

   Why? Before opening Grafana, make sure the samples are actually arriving and are not being rejected.

   Query the Mimir Prometheus API to count the series of the mimir job, then check that no sample has been rejected.

5. 5. Add the data source in Grafana

   Why? For Grafana, Mimir is just another Prometheus data source: only the /prometheus prefix changes.

   Create a Prometheus-type data source pointing to Mimir and plot rate(cortex_distributor_received_samples_total[1m]).

6. 6. See the blocks in MinIO

   Why? The first block is only uploaded once a 2-hour period closes: it is normal not to see anything straight away.

   Open the MinIO console (localhost:9001) or use mc to list the blocks bucket after two hours.

Difficulty level : ●●○○○ (2/5)