These Docker interview questions are examples of real tasks used by employers to screen job candidates such as web developers, front-end developers, back-end developers, and others that require knowledge of Docker containers and images.
1. Container Restart
The automation team is testing their background Docker web server containers. They need to cleanly remove the existing containers without leaving any artifacts behind, then start new containers.
Complete the following docker commands to achieve these objectives:
# Gracefully end all processes in the containers host> docker-compose stop # Remove the containers and their anonymous volumes host> docker-compose -v # Start containers in background host> docker-compose up apache php mysql
2. Container Lifecycle
As part of a load balancing scheme, your company uses multiple virtual machines which can provision and deprovision Docker containers as demand changes.
Complete the docker commands (with no additional arguments) that manage the lifecycle of a docker image.
- When a virtual machine completes startup, it runs the following command to ready the custom container image:
docker create --name balanced-container company-image
- When the load balancer detects high usage, it signals the virtual machine to make the container available for use. The VM runs the following command:
docker balanced-container
- The load balancer detects that a container has been underutilized for more than 15 minutes. It signals the VM to suspend the container to conserve CPU resources. The VM runs the command:
docker balanced-container
- Finding an increased load again, the load balancer signals the VM to awaken the container. The VM runs the command:
docker balanced-container
- After an hour of underutilization, the load balancer signals the VM to gracefully end all processes in the container to conserve RAM resources. The VM runs the command:
docker balanced-container
Docker Online Test (Easy)
Docker and DevOps Online Test (Easy)