Docker connects to a container through a port

Docker container connection

1. Network port mapping

We create a container for a python application

# docker run -d -P training/webapp python app.py

We create a container using the -P parameter and use docker ps to see that port 5000 is bound to host port 32768

We can also use the -p flag to specify that the container port should be bound to the host port.

The difference between the two methods is:

-P: The internal port of the container is randomly mapped to the high port of the host.

-p: Bind the container's internal port to the specified host port.

…… ...

# docker run -d -p 5000:5000 training/webapp python app.py

In addition, we can specify the network address bound to the container, such as binding 127.0.0.1

# docker run -d -p 127.0.0.1:5001:5000 training/webapp python app.py

In this way, we can access port 5000 of the container by accessing 127.0.0.1:5001

By default, containers are bound to TCP ports. If you want to bind to UDP ports, you can add /udp after the port.

# docker run -d -p 127.0.0.1:5000:5000/udp training/webapp python app.py

The docker port <images id> [port] command allows us to quickly view the port binding status

docker port ce206e3c0ae6 5000

Now we shut down all other containers and start a new nginx container

# docker run -d -p 5000:80 --name web111 nginx

We forward the container's port 80 to the local port 5000 and then access it externally

You can see that we can access it successfully, indicating that the port is forwarded.

2. Docker container connection

Port mapping is not the only way to connect Docker to another container.

Docker has a connection system that allows multiple containers to be connected together and share connection information.

A docker connection creates a parent-child relationship where the parent container can see the child container's information.

3. Container naming

When we create a container, Docker will automatically name it. But we can also use the --name flag to name the container

docker run -d -P --name Peithon training/webapp python app.py

Additional knowledge: How to view which ports are open inside a Docker container

You don't need to enter the container bash, just enter the docker port container id in the Linux command line to view it

The above article about how to connect a container through a port in Docker is all I have to share with you. I hope it can give you a reference. I also hope that you will support 123WORDPRESS.COM.