MySQL Database Monitoring with Prometheus

MySQL Database Monitoring with Grafana and Prometheus

Manikanta Grandhi

Manikanta Grandhi

Assosiate Software Engineer

Published Feb 14 2020

Database monitoring is different from infrastructure and application monitoring. It involves monitoring database performance, slow running queries, uptime, etc. It is essential because if a database goes down, it may bring the whole application to a standstill.

There are various tools that help in monitoring database, like Grafana, Kibana, netstat, etc. While Kibana only collects log metrics data, netstat is apt to displace connections and routing tables. Grafana labs give more performance visibility in comparison to others. It is an open-source metric analytics and visualization tool that enables developers to write plugins from scratch to integrate with several data sources.

Even if there is a failure, we can easily troubleshoot the issue with the available stats, like database connections, number of containers running and performance, number of bytes written and read, etc. This blog throws light on how to monitor MySQL database using Grafana and Prometheus.

For a comprehensive comparison between SQL and NoSQL databases, you may also read this blog.

Steps to Enable Monitoring of MySQL Database using Prometheus and Grafana

  1. Install and configure Grafana
  2. Install and configure Prometheus
  3. Install a database exporter
  4. Install the database

1. Install and Configure Grafana

Grafana helps in studying data, analytics, and monitoring over a period of time. It is also known as time-series analysis.

Installation steps:

Step 1: Go to Grafana’s official page and download Grafana for the respective operating system.

Execute:


wget https://dl.grafana.com/oss/release/grafana_6.5.1_amd64.deb
sudo dpkg -i grafana_6.5.1_amd64.deb


Step 2: Start the server

Execute:


sudo service grafana-server start
systemctl daemon-reload
systemctl start grafana-server
systemctl status grafana-server


This will start the Grafana server process with the Grafana user, which was created at the time of installation. The default HTTP port is 3000 (http://localhost:3000) and the default user and group is admin.

Default login and password of Grafana are: admin/admin

Default location Grafana will log into: /var/log/Grafana

Default Grafana log in window

Finally, when you hit the ip_address in the browser, the homepage will be shown as below:

Grafana homepage window

Enter your credentials in the login page, you will see the screen shown below:

Grafana log in dashboard

2. Install and configure Prometheus

Step 1: Go to Prometheus’ official page and copy the link address.

Using wget command, you can install the Prometheus and untar it.

Execute:


Wget
https://github.com/prometheus/prometheus/releases/download/v2.3.2/prometheus-2.3.2.linux-amd64.tar.gz
tar -xvf prometheus-2.3.2.linux-amd64.tar.gz
mv prometheus-2.3.2.linux-amd64 prometheus-files


Step 2: Create a Prometheus user, required directories, and make the Prometheus user as the owner of those directories.

Execute:


sudo useradd  /bin/false prometheus
sudo mkdir /etc/prometheus
sudo mkdir /var/lib/prometheus
sudo chown prometheus:prometheus /etc/prometheus
sudo chown prometheus:prometheus /var/lib/prometheus


Step 3: Copy Prometheus and promtool from the Prometheus-files folder to - /usr/local/bin and, after that, change the ownership to the Prometheus user.

Execute:


sudo cp prometheus-files/prometheus /usr/local/bin/
sudo cp prometheus-files/promtool /usr/local/bin/
sudo chown prometheus:prometheus /usr/local/bin/prometheus
sudo chown prometheus:prometheus /usr/local/bin/promtool


Step 4: Move the consoles and console library directories from Prometheus-files to /etc/Prometheus folder and change the ownership to the Prometheus user.

Execute:


sudo cp -r prometheus-files/consoles /etc/prometheus
sudo cp -r prometheus-files/console_libraries /etc/prometheus
sudo chown -R prometheus:prometheus /etc/prometheus/consoles
sudo chown -R prometheus:prometheus /etc/prometheus/console_libraries


Step 5: Create the Prometheus.yml file

Execute:


vi /etc/prometheus/prometheus.yml


Note: All Prometheus configurations should be present in /etc/Prometheus/Prometheus.yml file.

Step 6: Copy the following content into Prometheus.yml:


global
scrape_interval: 10s
 scrape_configs:
  - job_name: 'prometheus'
    scrape_interval: 5s
    static_configs:
      - targets: [<mention ip_address>:9090']


- follow the intendations in yml file, otherwise it raises an error.

Step 7: Change the ownership file to the Prometheus user

Execute:


sudo chown prometheus:prometheus /etc/prometheus/prometheus.yml


Step 8: Create a service file in this location - /etc/systmed/system

Execute:


sudo vi /etc/systmed/system/Prometheus.service


Step 9: Copy the following content to the 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=/etc/prometheus/consoles \
    --web.console.libraries=/etc/prometheus/console_libraries


[Install]


WantedBy=multi-user.target


Step 10: Reload the systemd service and start the Prometheus service

Execute:


sudo systemctl daemon-reload
sudo systemctl start Prometheus


To check the Prometheus status, run the command mentioned below

Execute:


sudo systemctl status Prometheus


The output should be shown as below:

Screen showing Prometheus service status

To Access the Prometheus web UI, use the default port 9090.

http://< prometheus-ip >:9090/graph

Prometheus web UI

3. Installing MySQL

Step 1: Install the latest version of MySQL

Execute:


wget https://dev.mysql.com/get/mysql57-community-release-el7-9.noarch.rpm 
sudo rpm -ivh mysql57-community-release-el7-9.noarch.rpm
sudo yum install mysql-server


Step 2: Start the daemon and enable it

Execute:


sudo systemctl start mysqld 
sudo systemctl status mysqld


Step 3: While installing it for the first time, we need to set a new password

Execute:


sudo grep 'temporary password' /var/log/mysqld.log


Output: 2019-12-11T09:28:50.095207Z 1 [Note] A temporary password is generated for root@localhost: pdpxle;Nt9*c

The last 12 digits make a password. After executing the command below, you will be prompted to set a new password. The password should be a combination of alphabets in lowercase, upper case, numbers, and a special character.

Execute:


sudo mysql_secure_installation


Output: If the existing password for the user account root has expired. Please set a new password.

New password:

The Estimated length of the password: 100

Change the password for root? (Press y|Y for Yes, any other key for No) :

Press yes all the times as many times as prompted. It is for security and old data clean up.

For Testing Mysql connection run the below command:


mysqladmin -u root -p version


When prompted, enter the new password to log in.

4. Installing the Mysqld exporter

Step 1: Download the latest version of mysqld_exporter

Execute:


mkdir mongodb-exporter
cd mongodb-exporter
wget https://github.com/prometheus/mysqld_exporter/releases/download/v0.11.0/mysqld_exporter-0.11.0.linux-amd64.tar.gz


Step 2: Extract the downloaded archive in your current folder

Execute:


tar xvzf mysqld_exporter-0.11.0.linux-amd64.tar.gz


Step 3: Create a user for Prometheus

Execute:


cd mysqld_exporter-0.11.0.linux-amd64/
sudo mv mysqld_exporter /usr/local/bin/

sudo useradd -rs /bin/false prometheus
sudo vi /lib/systemd/system/mysql_exporter.service


[Unit]


Description=MySQL Exporter
User=prometheus


[Service]


Type=simple
Restart=always
ExecStart=/usr/local/bin/mysqld_exporter \
--config.my-cnf /etc/.exporter.cnf \
--collect.auto_increment.columns \
--collect.binlog_size \
--collect.engine_innodb_status \
--collect.engine_tokudb_status \
--collect.global_status \
--web.listen-address=0.0.0.0:9104


[Install]


WantedBy=multi-user.target
sudo systemctl daemon-reload
systemctl status mysql_exporter


Output:

MySQL Exporter status screen

Default port is 9104 metrics for mysqld_exporter(http://< ip_address >:9104)

Metrics for Mysqld_exporter

Add it to Prometheus target.

Prometheus Targets page

Step 4: Set Prometheus as Grafana data source. Add the data source and name it as Prometheus. Enter the URL and click on Save & Test.

Adding Data source in Grafana

Step 5: Download the dashboards for Grafana

Execute:


Cd /etc/Grafana
Sudo mkdir  dashboards
Cd dashboards
Sudo wget https://github.com/percona/grafanadashboards/blob/master/dashboards/MySQL_Overview.json


Step 6: Import the MySql dashboard into Grafana

Go to Grafana dashboard. Run this Url in browser: http://< ip_address >:3000

On the left menu, click on the plus icon and click on import. Then, click on ‘Upload JSON file’ and go to the directory where the JSON file has been downloaded. Choose it to complete the upload.

Importing the MongoDB dashboard into Grafana

Importing Json file

Finally, your dashboard will be imported with real-time updates of MySQL.

MySQL Overview Dashboard

If you want to run a particular query: Go to Prometheus > click on Graph > click on insert metric: select the query in the drop-down menu that you want to execute > click on the execute button.

For example, to run a query to know how many connections are there, we run a query as shown below:

Running a Query in Grafana

Output:

It will display how many users are there currently in MySQL

Output screen of Connection_Status query

If you want a graph, click on the graph button, which will get executed as below:

Output screen of Connection_Status query

In Grafana, you will see the output as shown below:

Output screen of Connection_Status query

There are many monitoring tools available for data visualization, but Grafana labs give more performance visibility compared to others. Grafana and Prometheus help us monitor not only database servers but also the applications that are running on virtual machines as well as containers.