Prometheus Installation Demo

This guide walks through installing Prometheus as a systemd service on a Linux host. You’ll create a non-login system user, set up directories, install binaries and console files, deploy a systemd unit, and start the service. Follow the steps in order to ensure correct ownership and permissions. Quick overview:

Create a system user for Prometheus (non-login).
Create directories for configuration and data.
Install Prometheus binaries and console files.
Set ownership and permissions.
Install the Prometheus systemd service and start it.

Prerequisites

A Linux system with sudo privileges.
A Prometheus tarball downloaded from the official site (see links below), or the binaries available locally.
Basic familiarity with systemd, users, and file permissions.

Useful links

Prometheus downloads: https://prometheus.io/download/
systemd documentation: https://www.freedesktop.org/wiki/Software/systemd/

Table: resources created by this guide

Resource	Path	Purpose
Config directory	`/etc/prometheus`	Store `prometheus.yml`, `consoles`, and `console_libraries`
Storage directory	`/var/lib/prometheus`	TSDB storage for Prometheus
Binaries	`/usr/local/bin/prometheus`, `/usr/local/bin/promtool`	Prometheus server and utility

Create the prometheus user and directories

Create a non-login system user and the directories used by Prometheus:

# Create prometheus user (no home, no login)
sudo useradd --no-create-home --shell /usr/sbin/nologin prometheus

# Create config and data directories
sudo mkdir -p /etc/prometheus
sudo mkdir -p /var/lib/prometheus

Set ownership for the directories

Assign ownership of the new directories to the prometheus user and group so Prometheus can read/write appropriately:

sudo chown prometheus:prometheus /etc/prometheus
sudo chown prometheus:prometheus /var/lib/prometheus
sudo chmod 0755 /etc/prometheus /var/lib/prometheus

Install the Prometheus binaries

If you have not yet downloaded Prometheus, fetch the latest tarball from the official downloads page and extract it. Example using wget and tar:

# Example: download and extract (replace version as needed)
wget https://github.com/prometheus/prometheus/releases/download/v2.37.2/prometheus-2.37.2.linux-amd64.tar.gz
tar xvf prometheus-2.37.2.linux-amd64.tar.gz
cd prometheus-2.37.2.linux-amd64

From inside the extracted Prometheus directory, copy the prometheus and promtool binaries to /usr/local/bin and set ownership and executable permissions:

sudo cp prometheus /usr/local/bin/
sudo cp promtool /usr/local/bin/

# Ensure ownership and executable permissions
sudo chown prometheus:prometheus /usr/local/bin/prometheus /usr/local/bin/promtool
sudo chmod 0755 /usr/local/bin/prometheus /usr/local/bin/promtool

Install console files and the Prometheus configuration

Copy the consoles and console_libraries directories into /etc/prometheus so the web UI templates are available:

# From the extracted directory
sudo cp -r consoles /etc/prometheus/
sudo cp -r console_libraries /etc/prometheus/

Set ownership recursively so the prometheus user can read these files:

sudo chown -R prometheus:prometheus /etc/prometheus/consoles
sudo chown -R prometheus:prometheus /etc/prometheus/console_libraries

Copy your Prometheus configuration file (prometheus.yml) into place and set ownership:

sudo cp prometheus.yml /etc/prometheus/
sudo chown prometheus:prometheus /etc/prometheus/prometheus.yml

Make sure the configuration filename you copy matches the path referenced by the systemd service (below we reference /etc/prometheus/prometheus.yml). Also ensure the prometheus binary is executable and owned by the prometheus user.

Create the systemd service file

Create /etc/systemd/system/prometheus.service with the following contents. This unit uses the common startup options and paths used above:

[Unit]
Description=Prometheus
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/ \
  --web.console.templates=/etc/prometheus/consoles \
  --web.console.libraries=/etc/prometheus/console_libraries

[Install]
WantedBy=multi-user.target

Save the file after editing. If you use a different config path or binary location, update ExecStart accordingly.

Important: Ensure the --config.file and --storage.tsdb.path values in the systemd unit point to the exact files/directories you created. Mismatched paths are a common cause of startup failures.

Reload systemd, start and enable the service

Reload systemd so it picks up the new unit, then start and enable Prometheus to run at boot:

sudo systemctl daemon-reload
sudo systemctl start prometheus
sudo systemctl enable prometheus

Verify Prometheus is running

Check the service status:

sudo systemctl status prometheus

Look for an active (running) status. If there are problems, follow the logs to debug:

sudo journalctl -u prometheus -f

Common issues and quick fixes

Symptom	Likely cause	Fix
Service fails to start	Bad `--config.file` path or misconfigured `prometheus.yml`	Verify the file exists and syntax with `promtool check config /etc/prometheus/prometheus.yml`
Permissions denied on storage	Wrong ownership/permissions of `/var/lib/prometheus`	`sudo chown -R prometheus:prometheus /var/lib/prometheus`
Web UI unreachable	Firewall blocking port 9090 or Prometheus not running	Open port 9090 in firewall and verify service status

Example: verify config syntax with promtool:

/usr/local/bin/promtool check config /etc/prometheus/prometheus.yml

Access the Prometheus web UI

Open your browser to: http://localhost:9090 If you’re accessing remotely, replace localhost with your server IP or DNS name and ensure port 9090 is allowed through any firewall. If you need to adjust the listening address or port, see the Prometheus flags in the official docs. References and further reading

Prometheus download and releases: https://prometheus.io/download/
Prometheus configuration reference: https://prometheus.io/docs/prometheus/latest/configuration/configuration/
systemd unit documentation: https://www.freedesktop.org/wiki/Software/systemd/

End of lesson.

Introduction

Observability Fundamentals

Prometheus Fundamentals

PromQL

Dashboarding & Visualization

Application Instrumentation

Service Discovery

Push Gateway

Alerting

Monitoring Kubernetes

Conclusion

Scaling & Long Term Storage

Prometheus Installation Demo

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