SonarQube is an open-source platform for continuous inspection of code quality, supporting multiple languages including Java, C#, C/C++, and JavaScript through its plugin ecosystem. This guide details the deployement of a SonarQube server using Docker Compose and its integration with Maven for analyzing Java projects.

Prerequisites A CentOS 7 server with internet connectivity and JDK 11 installed is required. SonarQube version 8.2 and latter mandates JDK 11.

Installing Docker Engine Execute the following commands to install Docker:

sudo yum install -y yum-utils device-mapper-persistent-data lvm2
sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo
sudo yum install -y docker-ce docker-ce-cli containerd.io

Installing Docker Compose Download and set up Docker Compose:

sudo curl -L "https://github.com/docker/compose/releases/download/1.26.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
sudo chmod +x /usr/local/bin/docker-compose

Deploying SonarQube with Docker Compose Start the Docker service:

sudo systemctl daemon-reload
sudo systemctl start docker

Create a docker-compose.yaml file with the following configuration:

version: "3.8"
services:
  postgres_db:
    image: postgres:13
    networks:
      - sq_network
    environment:
      POSTGRES_USER: sonar_user
      POSTGRES_PASSWORD: sonar_pass
      POSTGRES_DB: sonarqube_db
    volumes:
      - postgres_data:/var/lib/postgresql/data

  sonarqube_server:
    image: sonarqube:8.2-community
    depends_on:
      - postgres_db
    networks:
      - sq_network
    ports:
      - "9000:9000"
    environment:
      SONAR_JDBC_URL: jdbc:postgresql://postgres_db:5432/sonarqube_db
      SONAR_JDBC_USERNAME: sonar_user
      SONAR_JDBC_PASSWORD: sonar_pass
    volumes:
      - sonarqube_data:/opt/sonarqube/data
      - sonarqube_extensions:/opt/sonarqube/extensions
      - sonarqube_logs:/opt/sonarqube/logs

networks:
  sq_network:
    driver: bridge

volumes:
  postgres_data:
  sonarqube_data:
  sonarqube_extensions:
  sonarqube_logs:

Launch the services in detached mode:

docker-compose up -d

Monitor the containre logs:

docker-compose logs -f sonarqube_server

Accessing SonarQube and Configuring Maven After deployment, access the SonarQube web interface at http://<server_ip>:9000. The default credentials are admin/admin.

To configure Maven for analysis, add the following profile to your settings.xml file:

<settings>
  <profiles>
    <profile>
      <id>sonar_scan</id>
      <activation>
        <activeByDefault>true</activeByDefault>
      </activation>
      <properties>
        <sonar.host.url>http://<server_ip>:9000</sonar.host.url>
        <sonar.login>admin</sonar.login>
        <sonar.password>admin</sonar.password>
      </properties>
    </profile>
  </profiles>
  <activeProfiles>
    <activeProfile>sonar_scan</activeProfile>
  </activeProfiles>
</settings>

Navigate to your Java project's root directory and execute:

mvn clean verify
mvn sonar:sonar

The analysis results will appear in the SonarQube dashboard after processing.

Troubleshooting Common Errors If you encounter the error max virtual memory areas vm.max_map_count [65530] is too low, apply this system parameter change:

# Temporary fix
sudo sysctl -w vm.max_map_count=262144

# Permanent fix: Add 'vm.max_map_count=262144' to /etc/sysctl.conf, then run:
sudo sysctl -p

Removing Docker and Its Images To uninstall Docker and clean up associated data:

1. List installed Docker packages:

   yum list installed | grep docker
   

2. Remove the packages:

   sudo yum remove docker-ce docker-ce-cli containerd.io -y
   

3. Delete all Docker data:

   sudo rm -rf /var/lib/docker