Docker is an open source containerization platform that helps users quickly create, deploy, and manage lightweight Linux containers for applications. Through Docker, users can package an application and all its dependencies into an independent container image and run it in various environments without worrying about environment differences and dependency conflicts. The process of building lightweight Linux containers using Docker will be introduced in detail below.
1. Introduction to Docker
Docker is based on container technology, which uses features such as cgroups and namespaces of the Linux kernel to achieve isolation and resource management. Compared with traditional virtual machines, Docker containers are more lightweight, faster to start, and have better portability and scalability. Here are the steps to build lightweight Linux containers using Docker:
2. Preparation work
1. Install Docker: First, you need to install Docker on the target machine. You can choose the appropriate installation method according to the operating system, such as apt-get, yum, brew, etc. After the installation is complete, start the Docker service.
2. Write Dockerfile: Dockerfile is Docker's build script, which is used to define the configuration and build process of the container image. In the preparation stage, users need to write a Dockerfile containing build instructions, specify the base image to be used, install dependencies, configure the environment, etc.
3. Write Dockerfile
Below is a simple example Dockerfile for building a lightweight Linux container containing a running Python application:
# 使用官方Python 3.9作为基础镜像
FROM python:3.9
# 设置工作目录
WORKDIR /app
# 将当前目录下的所有文件复制到工作目录
COPY . .
# 安装应用程序依赖项
RUN pip install --no-cache-dir -r requirements.txt
# 暴露应用程序使用的端口
EXPOSE 80
# 在容器启动时运行应用程序
CMD ["python", "app.py"]In the above example, the base image is first specified as the official Python 3.9 image. Then, set the working directory to /app and copy all files in the current directory to the working directory. Next, install the application’s dependencies by running the pip install command. Subsequently, use the EXPOSE directive to expose port 80 of the container, which will be used to access the application. Finally, use the CMD command to execute the python app.py command when the container starts to run the application.
4. Build container images
After finishing writing the Dockerfile, you can use the following command to build the container image:
docker build -t myapp:latest .Among them, the -t parameter is used to specify the name and label of the image, and . means using the current directory as the context to build the image. Docker will step by step execute the build process according to the instructions in the Dockerfile, install dependencies, configure the environment, and generate the final container image.
5. Run the container
After the container image is built, you can use the following command to start the container:
docker run -d -p 80:80 myapp:latestAmong them, the -d parameter indicates that the container runs in background mode, and the -p parameter specifies that the container's port 80 is mapped to the host's port 80. myapp:latest means using the newly built container image. Docker will start the container in the background and map the host's port 80 to the container's port 80, so that the application can be accessed through the host's port 80.
6. Manage containers
After running the container, you can manage it using the following commands:
- View the container list: The docker ps command can list the currently running containers.
- Stop the container: The docker stop <CONTAINER ID> command can stop the specified container.
- Delete a container: The docker rm <CONTAINER ID> command can delete the specified container.
- View logs: The docker logs <CONTAINER ID> command can view the log output of the container.
The above briefly introduces the process of using Docker to build lightweight Linux containers, including preparation, writing Dockerfile, building container images and running containers, etc. Through the containerization technology provided by Docker, users can easily create and manage application container environments to achieve a more efficient and portable deployment method. Using Docker can help users solve environment dependencies and configuration issues, and improve the efficiency of development and deployment.
7. Application development tools
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The principle is to concretize certain recurring scenes and processes in the development process into components, APIs, and database interfaces to avoid reinventing the wheel. This greatly improves programmers' productivity.
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This is a simple, cross-platform rapid development framework based on Java Boot/.Net Core. The front-end and back-end encapsulate thousands of common classes for easy expansion; it integrates a code generator to support front-end and front-end business code generation to meet rapid development and improve work efficiency; the framework integrates various commonly used classes such as forms, reports, charts, and large screens. Demo is easy to use directly; the back-end framework supports Vue2 and Vue3.
In order to support application development with higher technical requirements, from database modeling, Web API construction to page design, there is almost no difference from traditional software development. However, the low-code visualization mode reduces the repetitive labor of building "add, delete, modify and check" functions.
Deployment method
- jar ·
- Docker/Docker-Compose