What is a Docker Container?
Let’s see what a docker container is.
Before moving forward in this blog, read about Docker Image.
What is a container?
The container is nothing but a running instance of an image. When we download an image from the Docker hub, it’s a read-only file. We can run many containers using a single image. Docker container is a virtualized runtime environment that has isolation capabilities and separates the execution of applications from the local system. Every container is autonomous and runs its own isolated environment without disrupting the running applications of the system. This feature increases the security of an application.
We need to use the docker run command to make an image as a running instance which is nothing but a container. A container can run in many states like restarting, running, paused, excited, and dead. Use the docker ps command to see all the running containers.
docker ps -a command outputs both running and stopped containers.
As discussed above we can run multiple containers using a single image. These containers will have different ID’s but they come up with the same image. We can also run the same application more than one time which means that there will be two containers with the same application. Running multiple containers from the same image can be beneficial in some cases like for eg ., In case if one container fails the other containers will ensure that the application is still up and running. Every time Docker creates a container from an image, it forms a thin read-write layer on top of the image. This writable layer allows for changes to be made to the container, as the lower layers in the image are unchangeable. It also stores any changes made to the container during its entire runtime.
Key Takeaways
- Containers are running instances of an image.
- We can run multiple containers using a single image.
- Each container runs in an isolated environment without disrupting the running applications of a system.
- use docker run command to convert an image into a container.
- Whenever docker creates a container from the image there will be a writable layer that allows the changes to be made to the container and these changes last during their entire runtime.
Conclusion:
The container is a running instance of an image. After reading this article, you should now have a good understanding of what a Docker container is. Now that you know what a docker container read about the Docker image also so that you can understand more about it.
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