Containers Review Questions
Q. Rootless containers are less secure than rootful containers. True or False? A. False.
Q. Which of these—isolation, security, high transition time, less overhead—is not a benefit of the container technology? A. High transition time is not a container benefit.
Q. What is the name and location of the system-wide file that stores a list of insecure registries? A. The file that stores insecure registry list is called registries.conf and it lives in the /etc/containers directory.
Q. What is one thing that you do not get with rootless containers? Select from: security, ability to map privileged ports, ability to pass environment variables, or can be managed via systemd. A. The ability to map privileged ports is not directly supported with rootless containers.
Q. What is the significance of a tag in a container image? A. A tag is typically used to identify a version of the image.
Q. Which command would you use to inspect a container image sitting in a remote registry?
A. The skopeo command can be used to inspect an image located in a remote registry.
Q. What would you run to remove all locally stored images in one shot?
A. Execute podman rmi -a to remove all locally stored images.
Q. What is the default tag used with container images? A. The default tag is ’latest’ that identifies the latest version of an image.
Q. The per-user systemd service configuration file is stored under /etc/systemd/user directory. True or False? A. False. The per-user systemd unit configuration file is stored under the user’s home directory at ~/.config/systemd/user.
Q. Containers can be run on a bare metal server or in a virtual machine. True or False? A. True.
Q. Which feature would you use to allow traffic flow for your Apache web server running inside a container? A. Map a host port with a container port.
Q. How would you ensure that data stored inside a container will not be deleted automatically when the container is restarted? A. Attach a host directory to the container and use it for storing data that requires persistence.
Q. What is the name of the primary tool that is used for container management?
A. The primary container management tool is called podman.
Q. Which option must be included with the systemctl command to manage the state of a rootless container?
A. The --user option is required with the systemctl command to control the state of a rootless container.
Q. It is mandatory to download an image prior to running a container based off it. True or False? A. False. The specified image is automatically downloaded when starting a container.
Q. How would you connect to a container running in the background? A. Use the podman attach command to connect to a running container.
Q. By default, any data saved inside a container is lost when the container is restarted. True or False? A. True.
Q. What is the typical name of the file that furnishes instructions to build custom images? A. Containerfile is the typical name; however, you can use any name that you want.
Q. Can a single host directory be attached to multiple containers at the same time? A. Yes, a single host directory can be attached to multiple containers simultaneously.
Q. How would you ensure that a rootless container for a specific user is automatically started with the host startup without the need for the
user to log in?
A. Use the loginctl command as that user and enable lingering.
Q. What would you run to remove all stopped containers?
A. Run podman rm -a to remove all stopped containers.