Prometheus: Add authentication to Prometheus Node Exporter

This documentation is part of the Retrieving metrics from Linux guide. View the full guide here: How to retrieve Linux server metrics in Prometheus using Node Exporter.

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By default, Node Exporter does not perform authentication, meaning anyone can retrieve the exposed metrics. To secure access, you can add basic authentication for a user.

Generating a random password

Generate a password using the following commands:

password=`openssl rand -base64 32`
passwordHashed=`echo ${password} | htpasswd -inBC 10 "" | tr -d ':'`
echo "Clear password to keep for Prometheus server: ${password}"

If you do not have the htpasswd binary, you can install it on Debian/Ubuntu using apt-get install --no-install-recommends apache2-utils.

Keep the clear password secure as you will need it when configuring Prometheus.

Adding the user and restarting Node Exporter

Append the following lines to the configuration file to add a user called "prometheus" with the generated password hash:

sudo cat << EOF >> /etc/prometheus_node_exporter/configuration.yml
basic_auth_users:
  prometheus: ${passwordHashed}

EOF

# Restart Node Exporter
sudo systemctl restart node_exporter

Finally, verify that authentication is working correctly:

• Running curl http://localhost:9100/metrics should return "Unauthorized".
• Running curl -u prometheus:${password} http://localhost:9100/metrics should return the list of metrics.