[Prometheus & Grafana] Chapter 6. Installation

Note: This post is a summary based on the official Prometheus (v3.2.1) and Grafana documentation. For precise details, please refer to the official docs.

• Prometheus Official Docs
• Grafana Official Docs

---

Part 03, "Hands-On Setup," begins here. Chapter 5. Jobs and Instances wrapped up Part 02's coverage of the data model, metric types, and scraping structure. The theory is in place. Time to install and run Prometheus.

---

6.1 Binary Installation

Prometheus is written in Go and distributed as a single static binary. There are no external dependencies -- download, extract, and run.

Download

Grab the appropriate binary for your OS and architecture from the official releases page (https://prometheus.io/download/).

# Linux amd64 example
wget https://github.com/prometheus/prometheus/releases/download/v3.2.1/prometheus-3.2.1.linux-amd64.tar.gz

# Extract
tar xvfz prometheus-3.2.1.linux-amd64.tar.gz
cd prometheus-3.2.1.linux-amd64

Directory Structure

The extracted archive contains these files.

prometheus-3.2.1.linux-amd64/
├── prometheus          ← Prometheus server binary
├── promtool            ← Config validation and management tool
├── prometheus.yml      ← Default configuration file
├── consoles/           ← Console templates
├── console_libraries/  ← Console template libraries
├── LICENSE
└── NOTICE

Three items matter most: the prometheus binary, the promtool utility for config validation, and the default prometheus.yml config. The rest are console UI assets and license files.

Running Prometheus

# Run with default config
./prometheus --config.file=prometheus.yml

# With common flags
./prometheus \
  --config.file=prometheus.yml \
  --storage.tsdb.path=/var/lib/prometheus/data \
  --storage.tsdb.retention.time=30d \
  --web.listen-address=:9090 \
  --web.enable-lifecycle

Key Command-Line Flags

Flag	Default	Description
--config.file	prometheus.yml	Path to configuration file
--storage.tsdb.path	data/	TSDB data storage directory
--storage.tsdb.retention.time	15d	Data retention period
--storage.tsdb.retention.size	0 (unlimited)	Maximum storage size
--web.listen-address	:9090	Web UI and API listen address
--web.enable-lifecycle	false	Enable config reload via HTTP
--web.enable-remote-write-receiver	false	Enable remote write receiver

When both --storage.tsdb.retention.time and --storage.tsdb.retention.size are set, whichever limit is reached first triggers data deletion. The default retention is 15 days, which may need adjustment for production.

systemd Service Registration

For production deployments, managing Prometheus through systemd is standard practice.

# /etc/systemd/system/prometheus.service
[Unit]
Description=Prometheus Monitoring
Wants=network-online.target
After=network-online.target

[Service]
User=prometheus
Group=prometheus
Type=simple
ExecStart=/usr/local/bin/prometheus \
  --config.file=/etc/prometheus/prometheus.yml \
  --storage.tsdb.path=/var/lib/prometheus/data \
  --storage.tsdb.retention.time=30d \
  --web.listen-address=:9090 \
  --web.enable-lifecycle
ExecReload=/bin/kill -HUP $MAINPID
Restart=on-failure
RestartSec=5s

[Install]
WantedBy=multi-user.target

# Register and start the service
sudo systemctl daemon-reload
sudo systemctl enable prometheus
sudo systemctl start prometheus
sudo systemctl status prometheus

The ExecReload directive sends SIGHUP to reload the config file via systemctl reload prometheus. With --web.enable-lifecycle enabled, curl -X POST http://localhost:9090/-/reload achieves the same result.

---

6.2 Docker Installation

Docker eliminates the need to manage binaries directly.

Basic Run

docker run -d \
  --name prometheus \
  -p 9090:9090 \
  prom/prometheus

One command and Prometheus is running with default settings. Sufficient for testing.

Custom Config with Volume Mount

Production use requires mounting a custom config file and a persistent data volume.

docker run -d \
  --name prometheus \
  -p 9090:9090 \
  -v /path/to/prometheus.yml:/etc/prometheus/prometheus.yml \
  -v prometheus-data:/prometheus \
  prom/prometheus \
  --config.file=/etc/prometheus/prometheus.yml \
  --storage.tsdb.retention.time=30d

docker-compose

For multi-service setups, docker-compose keeps things organized.

# docker-compose.yml
version: '3.8'

services:
  prometheus:
    image: prom/prometheus:latest
    container_name: prometheus
    ports:
      - "9090:9090"
    volumes:
      - ./prometheus.yml:/etc/prometheus/prometheus.yml
      - ./rules:/etc/prometheus/rules
      - prometheus-data:/prometheus
    command:
      - '--config.file=/etc/prometheus/prometheus.yml'
      - '--storage.tsdb.retention.time=30d'
      - '--web.enable-lifecycle'
    restart: unless-stopped

volumes:
  prometheus-data:

There is no functional difference between binary and Docker installations. Docker fits naturally into container-based infrastructure; binary + systemd is simpler when containers are not already in use.

---

6.3 First Run and Status Pages

After starting Prometheus, open http://localhost:9090 in a browser to access the web UI.

Status > Targets

The http://localhost:9090/targets page shows the current state of all scrape targets. With default settings, only Prometheus itself appears.

Column	Description
Endpoint	Scrape target URL
State	UP (healthy) or DOWN (failed)
Labels	Labels applied to the target
Last Scrape	Timestamp of the last scrape
Scrape Duration	Time taken for the scrape
Error	Error message (when failed)

If State shows UP, everything is working. If DOWN, the Error column provides the cause.

Status > Configuration

The http://localhost:9090/config page displays the currently loaded configuration. Useful for verifying that config changes have been applied correctly.

Status > Runtime & Build Information

Prometheus version, Go version, build metadata, and storage details are all accessible here. This information is essential for debugging and issue reports.

---

6.4 Expression Browser

The built-in query interface is available at http://localhost:9090/query (or the Graph tab on the main page). It supports direct PromQL execution.

Table Tab

Displays Instant Query results in tabular form.

# Query Prometheus's own HTTP request counts
prometheus_http_requests_total

Result:

prometheus_http_requests_total{code="200", handler="/api/v1/query", ...}    142
prometheus_http_requests_total{code="200", handler="/metrics", ...}          89
prometheus_http_requests_total{code="200", handler="/targets", ...}          12

Each unique label combination appears as a separate time series.

Graph Tab

Renders Range Query results as a time-series graph. The time range is adjustable.

# Request rate over the last hour (5-minute window)
rate(prometheus_http_requests_total[5m])

The Table tab shows a point-in-time snapshot. The Graph tab shows trends over time.

Useful First Queries

Prometheus scrapes itself by default. These queries work immediately without any additional configuration.

Query	Description
up	Health status of all targets
process_resident_memory_bytes	Prometheus memory usage
prometheus_tsdb_head_series	Number of stored time series
scrape_duration_seconds	Scrape duration
prometheus_target_interval_length_seconds	Whether configured scrape intervals are being met

# 1. Health status of all targets
up

# 2. Prometheus memory usage
process_resident_memory_bytes

# 3. Number of stored time series
prometheus_tsdb_head_series

# 4. Scrape duration distribution
scrape_duration_seconds

# 5. Actual vs configured scrape intervals
prometheus_target_interval_length_seconds

Querying with promtool

Queries can also be executed from the command line without the web UI.

# instant query
./promtool query instant http://localhost:9090 'up'

# range query
./promtool query range http://localhost:9090 'rate(prometheus_http_requests_total[5m])' \
  --start='2026-03-26T00:00:00Z' \
  --end='2026-03-26T01:00:00Z' \
  --step=15s

promtool query instant returns the current value; promtool query range returns values across a specified time window. Both are useful in CI/CD pipelines and automation scripts.

---

Summary

Topic	Details
Binary install	Single Go binary, no dependencies, systemd registration recommended
Docker install	prom/prometheus image, mount config file and data volume
Web UI	localhost:9090, check Targets / Configuration / Runtime status
Expression browser	Table (Instant Query) / Graph (Range Query)
promtool	CLI-based querying, supports instant and range modes

Once Prometheus is running and the up query returns 1 in the web UI, installation is complete. The next chapter, Chapter 7. Configuration File (prometheus.yml), covers the structure of prometheus.yml and scrape configuration.