Application Deployment using Docker, Nginx as Load Balancer and MySQL as Database

Here I have used Docker to deploy an application, MySQL as its database and Nginx as load balancer i.e. Two Docker containers will communicate with one MySQL container with the help of Nginx container. I have complete setup ready on my github repository i.e. https://github.com/kailashv/php_mysql_lb.git

Please refer the repository mentioned above. There is Dockerfile for application, database and load balancer.

Technologies/Tools used :

• php
• MySQL
• Docker containerization
• Docker compose
• Nginx as load balancer.

Components :

• Dockerfile : Dockerfile for configuration of php application, MySQL and Nginx with all of its dependencies.
• Dcoker-compose.yml : Used to start multiple contaienrs at a time with one simple command.
• Folders : Containing all application files and configuration files.

Deployment :

• The php application is deployed over Docker Container.
• A Docker Image is created with all of its packages and dependencies.
• That image is availabe in the Docker Hub.
• That image is capable to run/deploy in any Linux platform.
• Two instance of php application is running, i.e. two Docker Containers are running on a machine with different ports.
• one instance of MySQL is running, i.e. one Docker container of MySQL.
• Nginx is used as load balancer.
• Nginx is also running in Docker Container.
• Nginx is linked with with apache instances i.e. application instance and all the requests are bieng forwarded/divided to apache via nginx load balancer.
• Nginx will distribute the load between two apche instances and accordingly both instances will communicate with MySQL Container.
• There are communication between all containers via Container linking.
• Nginx.cong is changed at runntime with the help of Dockerfile written to create image of nginx load balancer.
• These way we are achieving Load balancing between two apache instances and mysql.

Configuration :

• Dockefile : Please refer Dockerfile at all folders, containing all configurations and dependencies required by the application.
• Nginx.conf : The path of Nginx.conf file is /etc/nginx/nginx.conf , where all configurations are done.
• Provided a block “server” and upstream under “http” block.
• under server : provide all details of nginx endpoint.
• under upstream : provide all details of apache servers.
• Please refer the changes done at : folder nginx/nginx.conf

Steps to deploy this project :

• Clone the repo to your machine
• Go to folder where the docker-compose.yml file exist.
• Run command : $ docker-compose -up -d
• Which will run all the containers in sequence as mentioned in the docker-compose.yml file.
• If the image is not present in the machine, it will try to pull the image form public docker hub, once the image is pulled successfully, it will run as a Docker container.
• After successfull execution, check status of all running containers by command : $ docker ps
• This will show four running containers will of its details.
• The Php app are deployed over two containers with ports forwarded : 8081, 8082
• The MySQL port are forwarded to 3306
• The Nginx port is forwarded to 85
• So as per details mentioned above,
• we can access the application UI at : htttp://localhost:8081 or http://”machine_ip”:8081 htttp://localhost:8082 or http://”machine_ip”:8082
• we can access Nginx UI at : http://localhost:85 ot http://”machine_ip”:85
• Here we can check by stopping one instance of our application and still how requests are being processed by other instance.