introduction:
Docker is one of the most popular containerized platforms at present, and its flexibility and portability make it easy for developers to build, publish and run applications. Port mapping is an important concept when using Docker. This blog will introduce you to what port mapping is and provide you with some configuration guides and examples to help you successfully portmap Docker images.
What is port mapping?
Port mapping is a way to map ports inside Docker containers to ports on the host. Through port mapping, external networks can communicate with applications within Docker containers.
Steps to configure port mapping:
1. Create a Docker image:
First, you need to create a Docker image that will be the basis for the application you want to do port mapping. You can use Dockerfile to define your image and then build the image using the docker build command.
2. Select the port to map:
Before doing port mapping, you need to select the container port and host port to map. Typically, applications within a container listen for a specific port, and the port on the host is the port used by an external network to access the application.
3. Run the container and perform port mapping:
Use the docker run command to start the container and specify the port mapping rules through the -p option. The syntax for this option is <host port>:<container port>. For example, to map the 80 port of the container to the 8080 port of the host, you can use the following command:
docker run -p 8080:80 <Mirror name>
4. Verify port mapping:
After successfully running the container, you can verify that the port mapping is in effect by accessing the host's port 8080. If you have access to the application in the container, the port mapping is set correctly.
Example:
Suppose you have a web application based on which listens to the container's port 3000. You want to map the 3000 port of the container to the 8888 port of the host.
Here are the steps to configure port mapping:
Create a Dockerfile:
Create a file named Dockerfile in the root directory of the application and add the following:
FROM node:latest WORKDIR /app COPY . . RUN npm install EXPOSE 3000 CMD ["npm", "start"]
Build the image:
In the terminal, navigate to the directory where the Dockerfile is located and run the following command to build the image:
docker build -t myapp .
Run the container and do port mapping:
Run the following command to start the container and perform port mapping:
docker run -p 8888:3000 myapp
Verify port mapping:
Open the browser and enter http://localhost:8888 to access the application.
in conclusion:
With port mapping, you can easily expose applications within Docker containers to external networks. This blog introduces you to the concept of port mapping and provides some configuration guides and examples. Hope this information will be helpful for port mapping when using Docker. Have a great time using Docker!
This is the end of this article about the principles and implementation of Docker image port mapping. For more related Docker image port mapping content, please search for my previous articles or continue browsing the related articles below. I hope everyone will support me in the future!