How to Run a Docker Container in Interactive Mode?

Running a Docker container in interactive mode lets us work directly with the command line of the container. This mode is good for development, testing, or debugging. It gives us a live environment to run commands and see the results. When we run a Docker container in interactive mode, it stays open and ready for our inputs until we stop it.

In this article, we talk about the basics of running a Docker container in interactive mode. We will cover what interactive mode means and its benefits. We will also show how to use the Docker run command to start interactive containers. We will look at common options for these tasks. We will explain how to access the shell of a running container. Lastly, we will go through how to stop and remove an interactive container. We will also answer some frequently asked questions on this topic.

  • How Can You Run a Docker Container in Interactive Mode?
  • What is Interactive Mode in Docker?
  • How to Use the Docker Run Command for Interactive Containers?
  • What Are the Common Options for Running Containers Interactively?
  • How to Access the Shell of a Running Docker Container?
  • How to Stop and Remove an Interactive Docker Container?
  • Frequently Asked Questions

For more reading on related topics, we suggest these articles: What is Docker and Why Should You Use It?, What is a Docker Container and How Does It Operate?, and How to Install Docker on Different Operating Systems.

What is Interactive Mode in Docker?

Interactive mode in Docker lets us run a container and talk to it directly using the command line. This is very helpful for debugging, developing, or managing services inside the container. When we start a container in interactive mode, it opens a terminal session. This way, we can type commands and see results right away.

To run a Docker container in interactive mode, we use the -i (interactive) and -t (pseudo-TTY) options with the docker run command. This makes a virtual terminal and keeps the input open. So, we get an interactive shell experience.

For example, we can run a bash shell in an Ubuntu container with this command:

docker run -it ubuntu bash

In this example: - docker run starts a new container. - -it combines the -i and -t options for interactive mode. - ubuntu tells which image to use. - bash is the command we run in the container to start a Bash shell.

This mode is very important for tasks that need user input. It is also useful when we want to check the container’s filesystem and environment.

How to Use the Docker Run Command for Interactive Containers?

To run a Docker container in interactive mode, we use the docker run command with some flags for interactivity. The basic command looks like this:

docker run -it <image_name> <command>

Breakdown of the Command:

  • docker run: This starts a new container.
  • -i: This flag keeps STDIN open. This means we can interact with the container.
  • -t: This flag gives us a pseudo-TTY. It helps to have a terminal interface.
  • <image_name>: Here, we put the name of the Docker image we want to use. For instance, ubuntu or alpine.
  • <command>: This part is optional. We can put any command we want to run in the container, like /bin/bash for a shell.

Example:

To run an Ubuntu container and get a bash shell, we can use this command:

docker run -it ubuntu /bin/bash

This command pulls the Ubuntu image if we don’t have it already. Then it starts a new container and gives us an interactive bash shell. Now we can run commands inside the container.

Additional Notes:

  • If we just want to run a container and access the shell, we can use:
docker run -it <image_name>
  • For example:
docker run -it alpine

This command will give us access to the Alpine Linux shell.

Using the docker run command helps us create and manage interactive Docker containers. This is good for tasks like testing, debugging, and development directly in the container. For more about Docker concepts, you can visit What is Docker and Why Should You Use It?.

What Are the Common Options for Running Containers Interactively?

When we run Docker containers in interactive mode, we have many options. These options help us use our containers better. We can add these options in the docker run command to change how the container works.

  • -it: This combines two flags. The -i flag means interactive. The -t flag means pseudo-TTY. It lets us access the container’s shell interactively.
docker run -it ubuntu /bin/bash
  • –rm: This option removes the container when it exits. It is good for temporary containers. It helps us keep things clean.
docker run --rm -it ubuntu /bin/bash
  • -d: This runs the container in detached mode. We usually use this for background services. But we can use it with other options if we want.
docker run -d -it ubuntu /bin/bash
  • -v: This mounts a directory from our host into the container. It is great for sharing files between the host and the container.
docker run -it -v /host/path:/container/path ubuntu /bin/bash
  • –name: This option gives a name to the container. It makes it easier for us to refer to it later.
docker run --name my_container -it ubuntu /bin/bash
  • –network: This defines the network the container should join. This is important for networking setups.
docker run -it --network my_network ubuntu /bin/bash
  • -e: This sets environment variables inside the container. We can use this to set up applications running in the container.
docker run -it -e MY_ENV_VAR=value ubuntu /bin/bash

By knowing and using these common options, we can run and manage Docker containers interactively. This will help us improve our development and testing work. For more information about Docker and its parts, check out What Is Docker and Why Should You Use It?.

How to Access the Shell of a Running Docker Container?

To access the shell of a running Docker container, we can use the docker exec command. This command helps us run commands inside an existing container. Here is how we can do it:

  1. Identify the Container: First, we need to find the name or ID of the running container. We can do this with:

    docker ps

  2. Execute a Shell Command: Next, we use the docker exec command to start a shell session inside the container. For example, if we want to access a bash shell in a container called my_container, we run:

    docker exec -it my_container /bin/bash

    If the container does not have bash, we can use sh instead:

    docker exec -it my_container /bin/sh

  3. Interact with the Shell: Now we are inside the container. We can run any command like we are on the host machine.

  4. Exit the Shell: To leave the shell session, we just type exit.

This way is very important for fixing issues, running interactive apps, or doing admin tasks in the container. For more details about Docker containers and images, we can check what is a Docker container and how does it operate.

How to Stop and Remove an Interactive Docker Container?

We can stop an interactive Docker container with the docker stop command. You need to add the container ID or name after the command. If we are inside the interactive shell of the container, we can just type exit or press Ctrl + D. This will exit the shell and stop the container.

Stopping a Docker Container

To stop a container by its ID or name, we use:

docker stop <container_id_or_name>

Removing a Docker Container

After we stop the container, we can remove it using the docker rm command. This also needs the container ID or name:

docker rm <container_id_or_name>

Example Workflow

  1. First, we start an interactive container:
docker run -it ubuntu
  1. Next, we stop the container from another terminal:
docker ps          # This will show the container ID or name
docker stop <container_id_or_name>
  1. Then, we remove the container:
docker rm <container_id_or_name>

Important Notes

  • If we want to stop and remove the container in one command, we can use:
docker rm -f <container_id_or_name>

This command will stop and remove the container.

  • To see all containers, even the stopped ones, we can use:
docker ps -a

For more details about managing Docker containers, we can check how to run a Docker container in detached mode.

Frequently Asked Questions

1. What is the purpose of running a Docker container in interactive mode?

We run a Docker container in interactive mode so we can talk directly with the container’s command line. This is good for debugging, testing, and developing. It gives us real-time feedback. By using the Docker run command with -it flags, we can interact with the environment inside the container like we do with a local shell.

2. How do I run a Docker container in interactive mode?

To run a Docker container in interactive mode, we use the command docker run -it <image_name>. The -i flag keeps the input open. The -t flag gives us a pseudo-TTY. This lets us interact with the container’s shell. For example, if we run docker run -it ubuntu, it will start an Ubuntu container. Then we can run commands interactively.

3. Can I access the shell of a running Docker container?

Yes, we can access the shell of a running Docker container with the docker exec command. For example, if our container is called my_container, we run docker exec -it my_container /bin/bash to open an interactive bash shell. This lets us run commands in the running container without starting a new one.

4. How do I stop and remove an interactive Docker container?

To stop an interactive Docker container, we can use the exit command inside the container’s shell. Or we can use docker stop <container_id> from another terminal. To remove the stopped container, we run docker rm <container_id>. This way, we free all resources and keep our Docker environment clean for the next time.

5. What are the key differences between interactive mode and detached mode in Docker?

In interactive mode, we can talk directly with the container’s command line. This is very important for development and debugging. Detached mode runs the container in the background. It lets the container work without us having to interact with it. We can read more about running a Docker container in detached mode here. Knowing these modes helps us pick the best way for our Docker tasks.