Interview Questions and Answers in Docker : Part-1
Hello everyone, ‘Interview questions and answers in Docker‘, this article contains mostly asked interview questions and their answers. I am creating a series of questions and answers for beginners to advance.
'docker system prune' is mostly used to remove all unused images, containers, and networks. Volumes are not pruned by default.
Docker containers are designed to be stateless by default, meaning that data stored within the container itself is not persistent. However you can configure Docker to use volumes or bind mounts to persist data outside the container
Docker is an open-source platform that allows you to automate the deployment, scaling, and management of applications using containerization.
Docker lifecycle to the various stages as follows:
- Image Creation
- Container Creation
- Running state
- Stopped state
- Paused state
Overall, Docker provides a flexible and efficient way to manage and deploy applications, allowing for easy container creation, starting, stopping, and deletion while maintaining the state of containers as needed.
docker save and
docker load commands are used to save Docker images to a file and load them back into Docker, respectively. These commands are particularly useful when you need to transfer Docker images between different environments or when you want to back up your images for future use.
The default network driver in Docker is the
bridge network driver. When you run a Docker container without specifying a network driver, it automatically uses the
To change the network driver when running a Docker image, you can specify the desired driver using the
--network flag followed by the driver name. Here's an example:
docker run --network=<network-driver> <image>
<network-driver> with the name of the desired network driver and
<image> with the name of the Docker image you want to run.
latest tag for Docker images in a container orchestration environment can introduce potential problems and is generally not considered a best practice. Here's why:
- Lack of version control
- Non-deterministic behavior
- Inconsistent environments
Docker Swarm is a native clustering and orchestration solution provided by Docker.
The recommended network driver is the
overlay network driver.
Docker Compose is a tool provided by Docker that allows you to define and manage multi-container Docker applications.
Some key use cases and benefits of using Docker Compose:
- Define and orchestrate multi-container applications
- Easy setup and reproducibility
- Simplified local development
- Service scaling and load balancing
- Service dependencies and ordering
- Integration with Docker Swarm
ENTRYPOINTspecifies the command that is always executed when the container starts.
- It provides the primary command or executable for the container.
ENTRYPOINTis used in the Dockerfile, it will override any command specified with
ENTRYPOINTis typically used for defining the main application or process that runs inside the container.
CMDspecifies the default arguments for the command defined in
ENTRYPOINT, or it can be used to define the command itself if
ENTRYPOINTis not specified.
CMDis optional and can be overridden when running the container by providing a command or arguments as parameters.
- If both
ENTRYPOINTare specified in the Dockerfile, the
CMDvalues will be passed as arguments to the
ENTRYPOINTcommand when the container starts.
CMDis typically used to provide default settings or arguments for the main command specified in
ENTRYPOINT, but it can also be used to define a standalone command if
ENTRYPOINTis not used.