# Setup Prometheus Server on Red Hat Enterprise Linux 8

# Overview

Prometheus is an open-source and community-driven system monitoring and alerting. All metrics will be pulled, saved on a time-series database, and queried to display the metrics needed for monitoring. This article will show you how to set up a Prometheus Server on RHEL 8 (or RHEL 8-based distributions such as Alma Linux, Rocky Linux, and CentOS Stream).

# Pre-requisites

For this article, we just need one VM with:

* Registered and attached a subscription with Red Hat Enterprise Linux 8 licensed.
    
* Internet access for downloading dependencies is needed.
    
* Open access to port 9090 (default port for Prometheus).
    

# Steps

1. **Configure SELinux**
    
    > For your information, SELinux does not have a specific policy but you can use it along with SELinux enabled by following this article: [Installing Prometheus with SELinux](https://blog.kubesimplify.com/installing-prometheus-with-selinux) and passing this section.
    
    The step below will edit the SELinux configuration file and set it to permissive. Moreover, for current boot session we need to set permissive.
    
    ```bash
     vim /etc/selinux/config
    ```
    
    ```bash
    # This file controls the state of SELinux on the system.
    # SELINUX= can take one of these three values:
    #     enforcing - SELinux security policy is enforced.
    #     permissive - SELinux prints warnings instead of enforcing.
    #     disabled - No SELinux policy is loaded.
    SELINUX=permissive
    # SELINUXTYPE= can take one of these three values:
    #     targeted - Targeted processes are protected,
    #     minimum - Modification of targeted policy. Only selected processes are protected.
    #     mls - Multi Level Security protection.
    SELINUXTYPE=targeted
    ```
    
    ```bash
    setenforce permissive
    ```
    
2. **Download and extract Prometheus dependency**
    
    You can download freely from Prometheus’ GitHub release page and choose specific release version and environment. On this article, we using Prometheus 2.37.8 for Linux with AMD64 architecture.
    
    ```bash
    curl -L -o prometheus-2.37.8.linux-amd64.tar.gz https://github.com/prometheus/prometheus/releases/download/v2.37.8/prometheus-2.37.8.linux-amd64.tar.gz
    tar -xvf prometheus-2.37.8.linux-amd64.tar.gz https://github.com/prometheus/prometheus/releases/download/v2.37.8/prometheus-2.37.8.linux-amd64.tar.gz
    ```
    
3. **Setup Prometheus user and directory**
    
    We need to create a user for the Prometheus SystemD service. Moreover, we need to set up the downloaded and extracted files related to Prometheus, such as `prometheus.yml` (the default Prometheus configuration file), `prometheus` (the main binary file for running the server), and `promtool` (the binary file for validating any configuration for Prometheus), with all file ownership granted to the Prometheus user.
    
    ```bash
    useradd --no-create-home --shell /sbin/nologin prometheus
    mkdir /etc/prometheus /var/lib/prometheus
    touch /etc/prometheus/web.yml
    mv prometheus-2.37.8.linux-amd64/prometheus.yml /etc/prometheus/
    mv prometheus-2.37.8.linux-amd64/prometheus /usr/local/bin/
    mv prometheus-2.37.8.linux-amd64/promtool /usr/local/bin/
    chown prometheus:prometheus -R /etc/prometheus/ /usr/local/bin/prometheus /usr/local/bin/promtool /var/lib/prometheus
    ```
    
4. **Configure basic authentication for Prometheus**
    
    You may need to secure your Prometheus by adding an user and access Prometheus as pre-configured user and password. On Prometheus, all user credential will saved as a web config file and all password should be saved as Bcrypt hashes password. You can hash your password with Bcrypt using [Bcrypt-Generator.com](https://bcrypt-generator.com/) site or follow this article: [Basic auth](https://prometheus.io/docs/guides/basic-auth/).
    
    ```bash
    vim /etc/prometheus/web.yml
    ```
    
    ```yaml
    basic_auth_users:
      admin: [Bcrypt-hashes-passowrd]
    ```
    
5. **Configure Prometheus configuration**
    
    This configuration will add credential configuration for scraping jobs from Prometheus server metrics.
    
    ```bash
    vim /etc/prometheus/prometheus.yml
    ```
    
    ```yaml
    # my global config
    global:
      scrape_interval: 15s # Set the scrape interval to every 15 seconds. Default is every 1 minute.
      evaluation_interval: 15s # Evaluate rules every 15 seconds. The default is every 1 minute.
      # scrape_timeout is set to the global default (10s).
    
    # Alertmanager configuration
    alerting:
      alertmanagers:
        - static_configs:
            - targets:
              # - alertmanager:9093
    
    # Load rules once and periodically evaluate them according to the global 'evaluation_interval'.
    rule_files:
      # - "first_rules.yml"
      # - "second_rules.yml"
    
    # A scrape configuration containing exactly one endpoint to scrape:
    # Here it's Prometheus itself.
    scrape_configs:
      # The job name is added as a label `job=<job_name>` to any timeseries scraped from this config.
      - job_name: "prometheus"
    
        # metrics_path defaults to '/metrics'
        # scheme defaults to 'http'.
    
        static_configs:
          - targets: ["localhost:9090"]
        basic_auth:
          username: "admin"
          password: [Unhashes-password]
    ```
    
6. **Setup Prometheus service**
    
    Lastly, we should create a Prometheus’ service to run background. The prometheus service will enabled and run even the VM restarted.
    
    ```bash
    vim /etc/systemd/system/prometheus.service
    ```
    
    ```bash
    [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 \
    --web.config.file /etc/prometheus/web.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
    ```
    
    ```bash
    systemctl daemon-reload
    systemctl enable --now prometheus
    ```
    
    # Reference
    
    * Devopscube, “How To Install And Configure Prometheus Monitoring System On Linux,” *DevopsCube*, Oct. 21, 2020. [https://devopscube.com/install-configure-prometheus-linux](https://devopscube.com/install-configure-prometheus-linux)
        
    * J. Mutai, “How To Install Prometheus on RHEL 8 / CentOS 8,” *ComputingForGeeks*, Apr. 26, 2022. [https://computingforgeeks.com/how-to-install-prometheus-on-rhel-8](https://computingforgeeks.com/how-to-install-prometheus-on-rhel-8)
        
    * Leon, “Installing Prometheus with SELinux,” *Kubesimplify*, May 16, 2022. [https://blog.kubesimplify.com/installing-prometheus-with-selinux](https://blog.kubesimplify.com/installing-prometheus-with-selinux)
        
    * Prometheus, “Securing Prometheus API and UI Endpoints Using Basic Auth,” *Prometheus,* [https://prometheus.io/docs/guides/basic-auth](https://prometheus.io/docs/guides/basic-auth/)
        

> Revision:
> 
> 28/06/2023 - 10:53 PM: Add step to configuring Prometheus.