Using Docker network host commands

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Using Docker network host commands

Author：JIYIK Last Updated：2025/03/24 Views：

Docker containers work by leveraging network drivers that are created during the installation of Docker. The default drivers available to us include bridge and host networking.

When we create containers without specifying a network, they are added to the bridge network. If we want to add a network to the host network or a custom network, we use the --network command.

In this article, we will learn how to add a container to the host network using the --network command. We will also learn how to add a container to the default network if we do not specify a network using this command.

Create Nginx project

Open WebStorm IDEA and select File > New > Project . In the window that opens, select Empty Project and change the project name from untitled to docker-network-host or any preferred name.

Finally, press the button labeled Create to generate the project.

Create a file called index.html in the current folder and copy and paste the following code into the file.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<h1>Welcome to docker networking !</h1>
</body>
</html>

In this file, we have created a simple web page that will display a title when we visit the application running in the container. This will help verify that our container is running the Nginx application.

Defining an image

Create a file called Dockerfile and copy and paste the following instructions into it. Note that we typically use files with this name to create custom images from existing images.

FROM nginx:alpine
ADD . /usr/share/nginx/html

FROM - sets the base image on which we will create our custom image using the subsequent instructions.
ADD - Copies files and folders in the current folder to the image file system destination /usr/share/nginx/html.

Building an Image

Build our custom image using the Dockerfile defined above. Open a new terminal window using the keyboard shortcut ALT+F12 and build the image using this command.

~/WebstormProjects/docker-network-host$ docker build --tag docker-network-host:latest .

This command executes the Dockerfile in sequence to create a tagged image. We can view each running instruction in the terminal window as follows.

=> [1/2] FROM docker.io/library/nginx:alpine@sha256:082f8c10bd47b6acc8ef15ae61ae45dd8fde0e9f389a8b5cb23c37408642bf5d               0.1s
 => => resolve docker.io/library/nginx:alpine@sha256:082f8c10bd47b6acc8ef15ae61ae45dd8fde0e9f389a8b5cb23c37408642bf5d               0.1s
 => CACHED [2/2] ADD . /usr/share/nginx/html

Run the container in the default network driver

To run our application's container in the default network, execute the following command in a terminal window. Note that this container will be added to the bridge network.

~/WebstormProjects/docker-network-host$ docker run --name docker-network-bridge-test -d -p 8000:80 docker-network-host:latest

This command runs a container named docker-network-bridge-test that listens on port 80 in the container and exposes port 8000 on the host. To verify that this container has been added to the bridge network, execute the following command to check the bridge network.

~/WebstormProjects/docker-network-host$ docker network inspect bridge

Output:

[
    {
        "Name": "bridge",
        "Id": "45773c7633cf28baa742ceca9c054a8dd6b4ea609dd9944d7ae12bdb57e86bcd",
        "Created": "2022-10-06T07:53:45.935633743Z",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "172.17.0.0/16",
                    "Gateway": "172.17.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "5e452da9b047ce94ff23b4841d1cb3358f34b037ef566c2f12a9eb57012a5f85": {
                "Name": "docker-network-bridge-test",
                "EndpointID": "d3491eb0c518d91be71b170e8ca0a077e07781bffbe20f3e1a1fd415eef9c288",
                "MacAddress": "02:42:ac:11:00:02",
                "IPv4Address": "172.17.0.2/16",
                "IPv6Address": ""
            }
        },
        "Options": {
            "com.docker.network.bridge.default_bridge": "true",
            "com.docker.network.bridge.enable_icc": "true",
            "com.docker.network.bridge.enable_ip_masquerade": "true",
            "com.docker.network.bridge.host_binding_ipv4": "0.0.0.0",
            "com.docker.network.bridge.name": "docker0",
            "com.docker.network.driver.mtu": "1500"
        },
        "Labels": {}
    }
]

In the returned JSON, the Containers property has a container named docker-network-bridge-test with a MacAddress and an IPv4Address assigned. This is the same container that was created at the beginning of this section.

To serve this application on a browser, make a request to localhost:8000 (http://localhost:8000/) and make sure it returns a header containing the text Welcome to docker networking !.

Running containers in the host network

The term host network means that the container runs on our host's network, as the host network cannot containerize the container network. To run a container in the host network, execute the following command in the terminal window.

~/WebstormProjects/docker-network-host$ docker run --rm -d --network host --name docker-network-host-test docker-network-host:latest

This command runs a container named docker-network-host-test in the host network using the --network option with a value of host . To verify that this container was added to the host network, execute the following command in a terminal window.

~/WebstormProjects/docker-network-host$ docker network inspect host

Output:

[
    {
        "Name": "host",
        "Id": "4ce9d3806cd88f9d9ea446272f4338f7b1f5e7098d4d0bc2a11090c1759d1880",
        "Created": "2022-09-19T07:51:50.247290701Z",
        "Scope": "local",
        "Driver": "host",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": []
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "22d15c7eee861ec7fdfd22936c30dfe1d17b2dde52ada93256f3e30943a3ed80": {
                "Name": "docker-network-host-test",
                "EndpointID": "7bd01907c8b86a881b86ae9e9c8ad8c1d3aa9f0583adebb7d41ae15bd565fabe",
                "MacAddress": "",
                "IPv4Address": "",
                "IPv6Address": ""
            }
        },
        "Options": {},
        "Labels": {}
    }
]

In the returned JSON, the Containers property has a container called docker-network-host-test, note that in this case the container has no MacAddress or IPv4Adress assigned because it is running on the host network. This is the same container that was created at the beginning of this section.

To serve this application on a browser, make a request to localhost:80 (http://localhost:80/) and make sure it returns a header containing the text Welcome to docker networking!. However, make sure that port 80 on the host network is open to accept requests.

Summarize

In this article, we learned how to run containers on the default bridge network driver and the host network driver. Note that we used the --network command to add containers on a network other than the default network.

To ensure that your application runs on the new network, make sure that the port you are using is open for connections and that another process is not using that port.

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