How to start a stopped container?

Starting a Stopped Docker Container

In the world of Docker, managing the lifecycle of containers is a crucial aspect of container orchestration. When a Docker container is stopped, it can be restarted or resumed to continue its execution. This is a common task that Docker users often need to perform, whether it's to resume a paused application, restart a failed process, or simply continue a long-running task.

Identifying Stopped Containers

Before you can start a stopped container, you need to first identify which container is in the stopped state. You can use the docker ps -a command to list all containers, including those that are stopped.

docker ps -a

This command will display a list of all containers, including their status, which can be either "Up" (running) or "Exited" (stopped).

Starting a Stopped Container

Once you have identified the stopped container, you can use the docker start command to start it again. The basic syntax for this command is:

docker start <container_name_or_id>

Replace <container_name_or_id> with the name or ID of the container you want to start.

For example, if your stopped container has the name "my-app", you can start it with the following command:

docker start my-app

If the container was previously running and you want to resume its execution, you can use the docker restart command instead:

docker restart <container_name_or_id>

This command will first stop the container and then start it again.

Verifying the Container's Status

After starting the container, you can use the docker ps command to verify that the container is now running:

docker ps

This will display a list of all running containers, including the one you just started.

Handling Stopped Containers with Mermaid

To better understand the lifecycle of a Docker container, let's visualize it using a Mermaid diagram:

graph LR A[Create Container] --> B[Start Container] B --> C[Running] C --> D[Stop Container] D --> E[Stopped] E --> B[Start Container]

In this diagram, we can see the different states a Docker container can go through:

Create Container: A new container is created, but it is not yet running.
Start Container: The container is started and enters the "Running" state.
Running: The container is actively executing its workload.
Stop Container: The container is stopped, and it enters the "Stopped" state.
Stopped: The container is in a stopped state and can be restarted.

By understanding this lifecycle, you can effectively manage your Docker containers, including starting stopped containers when needed.

In conclusion, starting a stopped Docker container is a straightforward process that involves using the docker start or docker restart commands. By understanding the container lifecycle and visualizing it with a Mermaid diagram, you can better manage your Docker infrastructure and ensure your applications are running as expected.