Follow our detailed guide to install Prometheus on CentOS 7. Learn how to set up Prometheus for efficient system monitoring and advanced alerting capabilities. #centlinux #linux #prometheus
Table of Contents
What is Prometheus?
Prometheus is a free and open source software application used for event monitoring and alerting. It collects and records real-time metrics in a time series database and alert the users based on custom defined thresholds. Prometheus is written in Go programming language and distributed under Apache License 2.0.
Prometheus requires multiple exporters that must be installed on the target nodes. The exporter generates and publish the metrics on a relevant port on the target node. The Prometheus monitoring server will pull these metrics and store in a time series database. Following architecture diagram from Prometheus Documentation clarifies the concept and flow of the system.
In this guide, we will install Prometheus on CentOS 7 along with node_exporter.
Recommended Training for You: Grafana and Prometheus – Beginners Friendly Crash Course!
Prometheus Features
Following are the core features of Prometheus.
- Multi-dimensional data model
- Write powerful queries with PromQL
- Grafana integration for great visualization
- Efficient storage (in memory and disk) of time series data
- Precise alerts using Alertmanager
Environment Specification
We have configured a CentOS 7 based Linux virtual machine for this tutorial.
- CPU – 3.4 Ghz (2 cores)
- Memory – 2 GB
- Storage – 20 GB
- Operating System – CentOS 7.7
- Hostname – prometheus-01.example.com
- IP Address – 192.168.116.213 /24
Configure Prometheus Prerequisites
Connect with prometheus-01.example.com using ssh as root user.
As a best practice, we are creating a Linux user to own Prometheus software and processes.
# useradd --no-create-home -s /bin/false prometheus
Create required directories for Prometheus Software.
# mkdir /etc/prometheus # mkdir /var/lib/prometheus
Change owner and group of these directories to Prometheus.
# chown prometheus:prometheus /etc/prometheus # chown prometheus:prometheus /var/lib/prometheus
Install Prometheus on CentOS 7
You can download Prometheus event monitoring software from their official website or from it’s GitHub repository.
Here, we are downloading latest version of Prometheus Server with the help of wget Linux command.
# cd /tmp # wget https://github.com/prometheus/prometheus/releases/download/v2.13.1/prometheus-2.13.1.linux-amd64.tar.gz --2019-10-30 18:35:53-- https://github-production-release-asset-2e65be.s3.amazonaws.com/6838921/c0040780-f109-11e9-946c-40b97454e08d?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20191030%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20191030T133550Z&X-Amz-Expires=300&X-Amz-Signature=81f194c6a9222eee87bbb56c67c266703be220ddcdc754b9efb49f525b2b1338&X-Amz-SignedHeaders=host&actor_id=0&response-content-disposition=attachment%3B%20filename%3Dprometheus-2.13.1.linux-amd64.tar.gz&response-content-type=application%2Foctet-stream Resolving github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)... 52.216.24.44 Connecting to github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)|52.216.24.44|:443... connected. HTTP request sent, awaiting response... 200 OK Length: 57079650 (54M) [application/octet-stream] Saving to: âprometheus-2.13.1.linux-amd64.tar.gzâ 100%[======================================>] 57,079,650 240KB/s in 4m 24s 2019-10-30 18:40:19 (211 KB/s) - âprometheus-2.13.1.linux-amd64.tar.gzâ saved [57079650/57079650]
Extract downloaded zip file to install Prometheus on CentOS 7.
# tar xf prometheus-2.13.1.linux-amd64.tar.gz
Move Prometheus files to /var/lib/prometheus directory.
# mv prometheus-2.13.1.linux-amd64/* /var/lib/prometheus/
Adjust owner and group of /var/lib/prometheus directories.
# chown -R prometheus:prometheus /var/lib/prometheus
Prometheus zip file also contains a configuration file with default settings. We can use this file to configure our Prometheus server.
With the help of mv Linux command, move Prometheus configuration file to /etc/prometheus directory.
# cd # mv /var/lib/prometheus/prometheus.yml /etc/prometheus/
Create a soft link of prometheus executable file, so we can execute the prometheus command from CLI.
# ln -s /var/lib/prometheus/prometheus /usr/local/bin/prometheus
To setup autostart of Prometheus Server at the time of Linux startup, we need to create a Systemd service for Prometheus network monitoring tool as follows.
# vi /usr/lib/systemd/system/prometheus.service
And add following directives in that file.
[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=/var/lib/prometheus/consoles --web.console.libraries=/var/lib/prometheus/console_libraries [Install] WantedBy=multi-user.target
Enable and start Prometheus network service.
# systemctl enable --now prometheus.service Created symlink from /etc/systemd/system/multi-user.target.wants/prometheus.service to /usr/lib/systemd/system/prometheus.service.
Prometheus uses default service port 9090/tcp. We need to allow this port in Linux firewal, so the network traffic can reach to Prometheus server.
# firewall-cmd --permanent --add-port=9090/tcp success # firewall-cmd --reload success
Open URL http://prometheus-01.example.com using a web browser.
We are now at the Expression Browser web page. Here, we can search for the metrics, for which Prometheus is collecting data.
To see the graph of the data click on Graph.
Install Node_Exporter on CentOS 7
Prometheus receives metrics from many sources like machines, databases, applications, etc.
For this purpose, Prometheus requires an Agent (termed as Exporter) to be installed on each node, for which we want to collect metrics.
There are different types of exporters available at Prometheus website. We can download and use one, according to our requirement. But the most common Exporter that we prefer to install on each node to collect machine metrics is the node_exporter.
In this section, we are installing node_exporter on the same CentOS 7 based Prometheus event monitoring server.
Download Node_Exporter from it’s official download page.
# cd /tmp # wget https://github.com/prometheus/node_exporter/releases/download/v0.18.1/node_exporter-0.18.1.linux-amd64.tar.gz --2019-11-01 23:12:21-- https://github-production-release-asset-2e65be.s3.amazonaws.com/9524057/5dc5df80-86f1-11e9-924c-ef392e7300e3?X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWNJYAX4CSVEH53A%2F20191101%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20191101T181218Z&X-Amz-Expires=300&X-Amz-Signature=f5eae2939a77b2939f4299312aa5228aaee04471e15bde050c55db2a928212b2&X-Amz-SignedHeaders=host&actor_id=0&response-content-disposition=attachment%3B%20filename%3Dnode_exporter-0.18.1.linux-amd64.tar.gz&response-content-type=application%2Foctet-stream Resolving github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)... 52.216.100.91 Connecting to github-production-release-asset-2e65be.s3.amazonaws.com (github-production-release-asset-2e65be.s3.amazonaws.com)|52.216.100.91|:443... connected. HTTP request sent, awaiting response... 200 OK Length: 8083296 (7.7M) [application/octet-stream] Saving to: ânode_exporter-0.18.1.linux-amd64.tar.gzâ 100%[======================================>] 8,083,296 188KB/s in 84s 2019-11-01 23:13:46 (94.3 KB/s) - ânode_exporter-0.18.1.linux-amd64.tar.gzâ saved [8083296/8083296]
Extract downloaded files as follows.
# tar xf node_exporter-0.18.1.linux-amd64.tar.gz
Create a directory for node_exporter software.
# mkdir -p /var/lib/prometheus/node_exporter
Move extracted files to /var/lib/prometheus/node_exporter directory.
# mv node_exporter-0.18.1.linux-amd64/* /var/lib/prometheus/node_exporter # cd
Change ownership of node_exporter directory.
# chown -R prometheus:prometheus /var/lib/prometheus/node_exporter/
Create a systemd service for node_exporter, so it can be started automically during Linux server startup.
# vi /usr/lib/systemd/system/node_exporter.service
Add following lines of code in this file.
[Unit] Description=Node Exporter Wants=network-online.target After=network-online.target [Service] User=prometheus ExecStart=/var/lib/prometheus/node_exporter/node_exporter [Install] WantedBy=default.target
Enable and start node_exporter service.
# systemctl enable --now node_exporter.service Created symlink from /etc/systemd/system/default.target.wants/node_exporter.service to /usr/lib/systemd/system/node_exporter.service.
Node Exporter used default service port 9100/tcp. Therefore, we need to allow this service port in Linux firewall.
# firewall-cmd --permanent --add-port=9100/tcp success # firewall-cmd --reload success
Add a Node_Exporter Target in Prometheus Server
We have successfully installed node_exporter, now we have to add it as a target in Prometheus server.
Edit Prometheus configuration file.
# vi /etc/prometheus/prometheus.yml
and add following directives at the end of file.
- job_name: 'node_exporter'
static_configs:
- targets: ['localhost:9100']
Restart Prometheus service to take changes into effect.
# systemctl restart prometheus.service
Browse URL http://prometheus-01.example.com:9090/ and search for some node metrics there.
We are searching node_memory_MemAvailable_bytes metric here.
To see the graph of this metric click on Graph button.
Since, we have recently added this node to Prometheus Server, therefore, there isn’t much time series data available yet. Hence, we have adjusted time to 1m to fill the graph completely.
Read Also: How to install Grafana on CentOS 7
If you want to know more about Prometheus software than you should read Prometheus: Up & Running (PAID LINK) by O’Reilly Media.
Final Thoughts
Installing Prometheus on CentOS 7 is a key step towards setting up a robust monitoring and alerting system for your infrastructure. With the right setup, Prometheus will help you track metrics, visualize data, and manage alerts effectively. Whether you’re a systems administrator or an IT professional, mastering Prometheus will enhance your monitoring capabilities and streamline your operations.
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