How to Install Prometheus on Amazon Linux 2

In this article we are going to cover What is Prometheus, Why to use Prometheus, Prometheus  Architecture,Prometheus Components,How to Install Prometheus on Amazon Linux 2.

What is Prometheus?

• Prometheus is a open source Linux Server Monitoring tool mainly used for metrics monitoring, event monitoring, alert management, etc.
• Prometheus has changed the way of monitoring systems and that is why it has become the Top-Level project of Cloud Native Computing Foundation (CNCF).
• Prometheus uses a powerful query language i.e. “PromQL”.
• In Prometheus tabs are on and handles hundreds of services and microservices.
• Prometheus use multiple modes used for graphing and dashboarding support.

Why to use Prometheus?

• A multi-dimensional data model with time series data identified by metric name and key/value pairs
• PromQL, a flexible query language to leverage this dimensionality
• Pushing time series is supported via an intermediary gateway
• Multiple modes of graphing and dashboarding support

Prometheus  Architecture

As above we can see an architecture of Prometheus monitoring tool.

We made a basic design to understand it easily for you people.

Now lets understand the Prometheus components one-by-one

Prometheus Components

1. Prometheus Server

• Prometheus server is a first component of Prometheus architecture.
• Prometheus server is a core of Prometheus architecture which is divided into several parts like Storage, PromQL, HTTP server, etc.
• In Prometheus server data is scraped from the target nodes and then stored in the database.

1.a. Storage

• Storage in Prometheus server has a local on disk storage.
• Prometheus has many interfaces that allow integrating with remote storage systems.

1.b. PromQL

• Prometheus uses its own query language i.e. PromQL which is a very powerful querying language.
• PromQL allows the user to select and aggregate the data.

2. Service Discovery

• Next and very important component of Prometheus Server is the Service Discovery.
• With the help of Service discovery the services are identified which need to be scraped.
• To Pull metrics, identification of services and finding the targets are compulsory needed.
• Through Service discovery we monitor the entities and can also locate its targets.

3. Scrape Target

• Once the services are identified and the targets are ready then we can pull metrics from it and can scrape the target.
• We can export the data of the end point using node exporters.
• Once the metrics or other data is pulled, Prometheus stores it in a local storage.

4. Alert Manager

• Alert Manager handles the alerts which may occurs during the session.
• Alert manager handles all the alerts which are sent by the Prometheus server.
• Alert manager is one of the very useful components of the Prometheus tool.
• If in case any big error or any issue occurs, alert manager manage those alerts and contact with human via E-mail, Text Messages, On-call, or any other chat application service.

5. User Interface

• User interface is also an important component as it builds a bridge between the user and the system.
• In Prometheus, user interfaces are note that much user friendly and can be used till graph queries.
• For good exclusive dashboards Prometheus works together with Grafana (visualization tool).
• Using Grafana over Prometheus to visualize properly we can use custom dashboards.
• Grafana dashboards display via pie charts, line charts, tables, good data graphs of CPU usage, RAM utilization, network load, etc with indicators.
• Grafana supports and run with Prometheus by querying language i.e. PromQL.
• To fetch data from Prometheus and to display the results on Grafana dashboards PromQL is used.

Prometheus metrics

The Prometheus client libraries offer four core metric types.

1. Counter

A counter is a cumulative metric that represents a single monotonically increasing counter whose value can only increase or be reset to zero on restart.

2. Gauge

A gauge is a metric that represents a single numerical value that can arbitrarily go up and down.

3. Histogram

A histogram samples observations and counts them in configurable buckets.

4. Summary

Similar to a histogram, a summary samples observations. While it also provides a total count of observations and a sum of all observed values, it calculates configurable quantiles over a sliding time window.

How to Install Prometheus on Amazon Linux 2

Create a system user for Prometheus using below commands:

sudo useradd --no-create-home --shell /bin/false prometheus

Create the directories in which we will be storing our configuration files and libraries with this commands:

sudo mkdir /etc/prometheus
sudo mkdir /var/lib/prometheus

Set the ownership of the /var/lib/prometheus directory with below command:

sudo chown prometheus:prometheus /var/lib/prometheus

You need to inside /tmp :

cd /tmp/

Download prometheus using wget using below command, if you want download latest prometheus then visit prometheus download page

wget https://github.com/prometheus/prometheus/releases/download/v2.31.1/prometheus-2.31.1.linux-amd64.tar.gz

Extract the files using tar :

tar -xvf prometheus-2.31.1.linux-amd64.tar.gz

You need to inside prometheus-2.31.1.linux-amd64 so run the below command:

cd prometheus-2.31.1.linux-amd64

Move the configuration file and set the owner to the prometheus user:

sudo mv console* /etc/prometheus
sudo mv prometheus.yml /etc/prometheus
sudo chown -R prometheus:prometheus /etc/prometheus

Move the binaries and set the owner:

sudo mv prometheus /usr/local/bin/
sudo chown prometheus:prometheus /usr/local/bin/prometheus

Create the prometheus service file using below command:

sudo nano /etc/systemd/system/prometheus.service

Add the below line in this /etc/systemd/system/prometheus.service

[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

Reload systemd using below command:

sudo systemctl daemon-reload

Enable Prometheus service using below commands:

sudo systemctl enable prometheus

Start Prometheus service using below commands:

sudo systemctl start prometheus

Use below command to enable prometheus service in firewall or AWS security group.

sudo firewall-cmd --add-service=prometheus --permanent
sudo firewall-cmd --reload

Now Prometheus service is ready to run and we can access it from any web browser.

http://server-IP-or-Hostname:9090

Here are some snapshots of Prometheus dashboards and graphs.

Conclusion:

We have covered What is Prometheus, Why to use Prometheus, Prometheus  Architecture,Prometheus Components,How to Install Prometheus on Amazon Linux 2.

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• Install Prometheus and Grafana on Ubuntu 20.04 LTS
• Kubernetes cluster Monitoring with Prometheus and Grafana.