Principles and practices of the interaction between Docker images and containers and the execution o

Mondo Technology Updated on 2024-01-31

As a popular container technology, Docker has become an important tool for modern application development and deployment. In Docker, an image is the basis for building and running a container, and a container is an executable instance created from an image.

Docker image interaction with containers

Create a container: First, we need to create a container using a docker image. By using the Docker command line or the Docker API, we can specify the desired image and container configuration options to create the container. For example, use the following command to create a file named"mycontainer"Containers:

docker create --name mycontainer myimage
Start the container: Once the container is created, we can start it with the following command:

docker start mycontainer
Enter the container: To interact with the container, we can enter the command line interface of the container using the following command:

docker exec -it mycontainer bash
With this command, we can execute commands inside the container, view the container's file system, modify the configuration file, etc.

Communicate with containers: Docker containers can communicate with the external environment in a variety of ways. For example, we can map a container's port to a port on the host so that applications inside the container can be networked. In addition, Docker supports features such as network connectivity, shared file volumes, etc., for communication and data sharing between containers and other containers or hosts.

Principles and practices of executing ** inside a container

Command-line interaction: The easiest way to do this inside a container is through command-line interaction. By entering the command line interface of the container, we can execute various commands inside the container. For example, run a python script inside a container:

python script.py
Automation scripts: If we need to automate some of the ** when the container starts, we can write these ** to a startup script and specify the execution path of the script in the dockerfile. For example, add the following directive to the dockerfile:

copy startup.sh /root/


cmd ["/bin/bash", "/root/startup.sh"]
This way, every time you start a container, docker automatically executes a startupsh script.

Containerized applications: For complex applications, we can containerize them, i.e., package the application and its dependencies into a single image and run inside the container. Containerized applications can define the build process through a dockerfile and control its behavior through various configurations and environment variables. For example, here's a simple dockerfile example:

from python:3.9


copy . /app


workdir /app


run pip install -r requirements.txt


cmd ["python", "app.py"]
This dockerfile uses python 39. As the base image, copy the files in the current directory to the app directory of the container, and install the required python dependencies inside the container. Finally, it does this by executing the apppy to start the application.

Container orchestration: For complex applications, multiple containers are often required to work together. In this case, we can use a container orchestration tool such as Docker Compose or Kubernetes to manage and orchestrate multiple containers. Container orchestration tools allow us to define dependencies, network connections, resource allocation, etc., between multiple containers, and provide automated deployment and scaling capabilities.

The interaction between a docker image and a container is achieved by creating and starting a container. We can execute inside a container using things like command-line interactions, automation scripts, and containerized applications. By leveraging Docker's capabilities and tools, we can easily build, manage, and scale containerized environments for applications, enabling more efficient, flexible, and reliable application development and deployment.

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