Dockerizing WordPress and Database Optimization

This project involves Dockerizing a WordPress application and optimizing the database for improved performance. Follow these instructions to set up the project.

Table of Contents

1. Dockerization
   • Dockerfile
   • Docker Compose
2. How to setup
3. Database Optimization
4. Additional Notes

Dockerization

Dockerfile

I started by creating a Dockerfile for WordPress, using the latest image of Wordpress.

# Use the official WordPress image as the base image
FROM wordpress:latest

# Then defined the environmental variables for database configuration
ENV WORDPRESS_DB_HOST=db
ENV WORDPRESS_DB_USER=root
ENV WORDPRESS_DB_PASSWORD=my-secret-password
ENV WORDPRESS_DB_NAME=my_wordpress_db

# Services Configuration
# No need to start apache service as wordpress image already have the configuration for this function.

Docker Compose

Then defined services and network in Docker Compose configuration:

• wordpress: In the wordpress service, specified the build context, port mapping, common network to configure the connection to the database. Also used "depends_on" keyword, to make sure that database container is started before wordpress container.

• db: Then put mysql service, along with the environment variable, volume attachment and common network.

• network: Then create a network mynetwork so that the wordpress image can use database name to point to database in place of IP address, as on restarting the container the IP address of the database container can be changed but if both the containers are in same network then wordpress can be connected database container using the name of the container.

version: '3.8'
services:
  wordpress:
    build:
      context: .
      dockerfile: Dockerfile
    ports:
      - "80:80"
    depends_on:
      - db
    networks:
      - mynetwork
  db:  
    image: mysql:latest
    volumes:
      - ./mysql_data:/var/lib/mysql
    environment:
      MYSQL_ROOT_PASSWORD: my-secret-password
      MYSQL_DATABASE: my_wordpress_db
      MYSQL_QUERY_CACHE_TYPE: 1
      MYSQL_QUERY_CACHE_SIZE: 64M
    networks:
      - mynetwork
networks:
  mynetwork:
    driver: bridge

Setup

Download both files Dockerfile and docker-compose.yml in same directory, then run the following command:

docker-compose up -d

Make sure that you are in the same directory in which the above files are present.

Database Optimization

Here is a list of some of the techniques used in optimisation of database.

• Indexing: Indexing in a database is the process of creating data structures (indexes) that significantly speed up data retrieval operations by providing quick access to specific rows in a table based on the indexed column values.

• Caching: Caching in a database involves temporarily storing frequently accessed data in memory to reduce the need for repeated disk reads.

• Query Optimisation: The process of selecting an efficient execution plan for processing a query is known as query optimization.

• Database Tuning: In this, we adjust database server settings like buffer sizes and connection limits. These optimizations aim to enhance the overall performance.

In this setup I have used Caching because caching can be easily scaled by adding more memory, which is often more cost-effective than scaling the database infrastructure. It also decreases the load on the database server, freeing up resources for other operations. Compared to other optimization techniques like indexing and query optimization, caching provides immediate performance benefits without the need for complex query rewriting or restructuring. However, it is most effective when used in conjunction with other optimization strategies for comprehensive database performance improvements.

For caching, I have implemented two environmental variables in the docker-compose file:

MYSQL_QUERY_CACHE_TYPE: 1
MYSQL_QUERY_CACHE_SIZE: 64M

MYSQL_QUERY_CACHE_TYPE is an environment variable used to specify the query cache type in MySQL. The value 1 indicates that the query cache is enabled and will be used for caching query results.

MYSQL_QUERY_CACHE_SIZE is an environment variable used to set the size of the query cache in MySQL. The value 64M specifies the size of the query cache as 64 megabytes (MB).

Additional Notes

The above setup have one vulnerability, that is the password of the database is given in open and anyone can see the password, which is not a good use case. So for rectifying this issue, we can use one functionality of docker swarm that is "secret" and we can make secret using the following command but before this we have to make the docker swarm active.

docker swarm init

echo -n "mysql_root_password" | docker secret create my-secret-password -

This is will make the password secure and we can use it in docker-compose file by using MY_SQL_PASSWORD_FILE: /run/secret/my-secret-password and before this we have to use one more block that is secret and give it the name of the secret.

MY_SQL_PASSWORD_FILE: /run/secret/my-secret-password

secrets:
  mysql_root_password:
    external: true

Also we can see our secret using following command:

docker secret ls