Containerization with Docker - Quiz

No.	Training Unit	Lecture	Training content	Question	Level	Mark	Answer	Answer Option A	Answer Option B	Answer Option C	Answer Option D	Explanation
1	Unit 1: Containerization with Docker	Lec1	Containers vs VMs	What is a key difference between containers and virtual machines?	Easy	1	A	Containers share the host OS kernel	Containers include a complete guest OS	Containers use hardware virtualization	Containers require a hypervisor	Containers share the host OS kernel, making them lightweight and fast to start, while VMs run complete operating systems on virtualized hardware.
2	Unit 1: Containerization with Docker	Lec1	Container Startup	Compared to virtual machines, containers typically start in:	Easy	1	B	Minutes	Seconds or less	Hours	The same time as VMs	Containers start in seconds or less due to their lightweight nature, while VMs take minutes because they boot a complete OS.
3	Unit 1: Containerization with Docker	Lec1	Docker Concepts	What is a Docker image?	Easy	1	C	A running process in Docker	A container management tool	A read-only template for creating containers	A Docker configuration file	A Docker image is a read-only template containing instructions for creating a Docker container - think of it as a snapshot or blueprint.
4	Unit 1: Containerization with Docker	Lec1	Docker Concepts	What creates a new layer in a Docker image?	Easy	1	D	ENV instruction only	EXPOSE instruction only	WORKDIR instruction only	RUN, COPY, and ADD instructions	Each RUN, COPY, and ADD instruction in a Dockerfile creates a new layer. Layers are cached and reused to speed up builds.
5	Unit 1: Containerization with Docker	Lec1	Docker Commands	Which command is used to list all containers including stopped ones?	Easy	1	B	docker ps	docker ps -a	docker list –all	docker containers	The docker ps -a command lists all containers including stopped ones, while docker ps only shows running containers.
6	Unit 1: Containerization with Docker	Lec1	Port Mapping	In the command docker run -p 8080:80 nginx, what does 8080 represent?	Medium	2	A	The host port	The container port	The nginx version	The protocol number	In port mapping syntax -p HOST:CONTAINER, 8080 is the host port and 80 is the container port. Traffic on host port 8080 is forwarded to container port 80.
7	Unit 1: Containerization with Docker	Lec1	Volumes	What is the purpose of Docker volumes?	Easy	1	C	To increase container memory	To speed up container startup	To persist data beyond container lifecycle	To share CPU resources	Volumes persist data beyond container lifecycle. Without volumes, data inside containers is lost when the container is removed.
8	Unit 1: Containerization with Docker	Lec1	Dockerfile Best Practices	Why should dependency files be copied before application code in a Dockerfile?	Medium	2	B	To reduce image size	To maximize layer caching	To improve security	To speed up container startup	Docker caches layers and reuses them if unchanged. Copying dependency files first means dependencies only rebuild when they change, not on every code change.
9	Unit 1: Containerization with Docker	Lec1	Layer Optimization	What is the best practice for running multiple apt-get commands in a Dockerfile?	Medium	2	A	Combine them in a single RUN instruction	Use separate RUN instructions for each	Use a shell script	Run them in the CMD instruction	Combining commands in a single RUN instruction minimizes layers. Multiple RUN commands create unnecessary layers and increase image size.
10	Unit 1: Containerization with Docker	Lec1	Base Images	Which Python base image variant is recommended for production?	Medium	2	B	python:3.13	python:3.13-slim	python:3.13-alpine	python:3.13-full	The -slim variants are recommended for production as they have a good balance of size (~150MB) and compatibility. Alpine can have pip compile issues.
11	Unit 1: Containerization with Docker	Lec1	Base Images	Why should you avoid using the latest tag for base images in production?	Medium	2	C	It uses more disk space	It’s slower to download	It can change unexpectedly and break builds	It’s not supported by Docker Hub	Using latest tags can lead to non-deterministic builds. When the upstream image updates, your builds may break unexpectedly.
12	Unit 1: Containerization with Docker	Lec1	Multi-stage Builds	What is the primary benefit of multi-stage Docker builds?	Medium	2	A	Smaller final images	Faster build times	More secure builds	Better caching	Multi-stage builds allow you to use build tools in one stage and copy only runtime artifacts to the final stage, resulting in much smaller production images.
13	Unit 1: Containerization with Docker	Lec1	Multi-stage Builds	In a multi-stage build, how do you copy files from a previous stage named “builder”?	Medium	2	D	COPY builder:/path /dest	COPY –stage=builder /path /dest	COPY [builder] /path /dest	COPY –from=builder /path /dest	The syntax COPY --from=builder /source /dest copies files from a named stage to the current stage.
14	Unit 1: Containerization with Docker	Lec1	Security	Why should containers run as non-root users?	Medium	2	B	To improve performance	To limit damage if an attacker exploits a vulnerability	To reduce image size	To enable volume mounting	Running as root is a security risk. If an attacker exploits a vulnerability, they gain root access to the container and potentially the host.
15	Unit 1: Containerization with Docker	Lec1	Security	Where should secrets like database passwords be stored in Docker?	Easy	1	D	In the Dockerfile ENV instruction	In the Docker image	In the source code	Injected at runtime via environment variables or Docker secrets	Secrets should never be stored in Dockerfiles or images. They should be injected at runtime using environment variables or Docker/Kubernetes secrets.
16	Unit 1: Containerization with Docker	Lec1	.dockerignore	What is the purpose of a .dockerignore file?	Easy	1	A	Exclude files from the build context	Ignore Docker commands	Skip certain Dockerfile instructions	Disable Docker caching	A .dockerignore file excludes unnecessary files from the build context, reducing build time and preventing sensitive files from being included in images.
17	Unit 1: Containerization with Docker	Lec1	Docker Commands	Which command shows real-time resource usage of running containers?	Easy	1	C	docker top	docker inspect	docker stats	docker logs	The docker stats command shows real-time resource usage (CPU, memory, network I/O) of running containers.
18	Unit 1: Containerization with Docker	Lec1	Healthchecks	What does a HEALTHCHECK instruction do in a Dockerfile?	Medium	2	B	Checks host system health	Defines a command to test if the container is working correctly	Validates the Dockerfile syntax	Monitors disk space	HEALTHCHECK defines a command that Docker runs periodically to check if the container application is healthy and functioning correctly.
19	Unit 1: Containerization with Docker	Lec1	Security	What does the --cap-drop=ALL flag do when running a container?	Hard	3	A	Removes all Linux capabilities from the container	Disables all networking	Prevents all file operations	Stops all processes	The --cap-drop=ALL flag removes all Linux capabilities, following the principle of least privilege. You can then add back only required capabilities.
20	Unit 1: Containerization with Docker	Lec1	Container Isolation	What technology does Docker use for process-level isolation on Linux?	Hard	3	D	Hypervisor	Virtual machines	Hardware virtualization	Linux namespaces and cgroups	Docker uses Linux namespaces for isolation (process, network, mount) and cgroups for resource limiting (CPU, memory).