How to setup Promtail in Ubuntu 20.04

Promtail is an agent which ships the contents of local logs to Loki instance. It is usually deployed to every machine that has applications needed to be monitored.

It primarily:

• Discovers targets
• Attaches labels to log streams
• Pushes them to the Loki instance

In this article i’m using Promtail version 2.4.1.

Prerequisites

Loki already configured (check this article on how to setup Loki)

Grafana already configured

A Running Application which needs to be monitor (For this article I’m using NGINX)

Install Promtail

Download Promtail binary according to your system and CPU architecture from here.

I’m system is Linux and CPU architecture is amd64. To check CPU architecture run below command.

#check cpu architecture
uname -a
#example for Loki on the linux operating system and amd64 architecture
curl -O -L "https://github.com/grafana/loki/releases/download/v2.4.1/promtail-linux-amd64.zip"
#extract the binary
unzip "promtail-linux-amd64.zip"
#make sure it is executable
chmod a+x "promtail-linux-amd64"
#copy binary to /usr/local/bin/
sudo cp promtail-linux-amd64 /usr/local/bin/promtail
#verify installation by checking version
promtail --version

Now, it’s time create config file for Promtail.

#create dir in /etc
sudo mkdir -p /etc/promtail /etc/promtail/logs
#promtail config file for nginx
sudo curl -o /etc/promtail/promtail-config.yaml -L "https://gist.githubusercontent.com/theLazyCat775/6fe9125e529221166e9f02b00244638a/raw/84f510e6f62d0e60ab95dbe7f9732a629a27eb6d/promtail-config.yaml"

Configure Promtail to run as a service.

#Create a file called promtail.service
sudo vi /etc/systemd/system/promtail.service

Add the script and save.

[Unit] 
Description=Promtail service 
After=network.target 
 
[Service] 
Type=simple 
User=root 
ExecStart=/usr/local/bin/promtail -config.file /etc/promtail/promtail-config.yaml 
Restart=on-failure 
RestartSec=20 
StandardOutput=append:/etc/promtail/logs/promtail.log 
StandardError=append:/etc/promtail/logs/promtail.log 
 
[Install] 
WantedBy=multi-user.target

Run below command to start promtail as a service.

sudo systemctl daemon-reload #To reload systemd
sudo systemctl start promtail #to start promtail
sudo systemctl status promtail #to check status
sudo systemctl restart promtail #to restart

You can check logs of Loki at /etc/promtail/logs/promtail.log

Enable Promtail on system boot.

sudo systemctl enable promtail.service

Now Promtail is successfully installed and running as service in Ubuntu 20.04.