Running Docker Containers

Once you have created a Docker image, the next step is to run it as a container. Docker provides a simple and efficient way to run containers on your local machine or in a production environment.

Running a Docker Container

To run a Docker container, you can use the docker run command followed by the name or ID of the image you want to run. For example, if you have an image called myapp-image, you can run it with the following command:

1docker run myapp-image

This command will start a new container based on the specified image.

Managing Docker Containers

Docker provides various commands to manage running containers.

• To list all running containers, you can use the docker ps command.
• To stop a running container, you can use the docker stop command followed by the container ID or name.
• To remove a stopped container, you can use the docker rm command followed by the container ID or name.

Controlling Container Resources

Docker allows you to control the resources allocated to a container, such as CPU and memory.

• To limit the CPU usage of a container, you can use the --cpus option followed by the number of CPUs you want to allocate. For example, --cpus 0.5 would limit the container to use only 50% of a single CPU.
• To limit the memory usage of a container, you can use the --memory option followed by the amount of memory you want to allocate. For example, --memory 512m would limit the container to use only 512 megabytes of memory.

Example: Running a Spring Boot Application

Let's say you have a Spring Boot application packaged as a JAR file. You can run it as a Docker container using the following command:

1# Build the Docker image
2docker build -t myapp-image .
3
4# Run the Docker container
5docker run -p 8080:8080 myapp-image

This command builds the Docker image using the Dockerfile located in the current directory (.) and tags it as myapp-image. Then it runs the container from the built image and maps port 8080 on the host to port 8080 inside the container.

Congratulations! You have learned how to run Docker containers and manage them effectively. In the next lesson, we will explore Docker networking and how to create networks for your containers.

xxxxxxxxxx

class Main {

    public static void main(String[] args) {

      // Replace with your Java logic here

      System.out.println("Hello, Docker!");

    }

}