EX188 Practice Questions 1 — 50 Questions

Question 1

You want to ensure that if any command in a multi-command RUN instruction fails, the entire container build process fails immediately. What shell option should be set or is default in Containerfiles?

Accepted Answer

RUN set -e && command1 && command2. By default, the shell used in shell form runs with /bin/sh -c. To ensure failures propagate, strict error handling like set -o pipefail can be used.

Answer

RUN --strict-error command1 && command2

Answer

BUILD --fail-on-error

Answer

RUN ignore-errors=false command1 && command2

Question 2

An administrator is troubleshooting a container that fails its health check repeatedly. The container definition needs a health check that runs curl -f http://localhost/ || exit 1 every 30s, with a 5s timeout and 3 retries, starting after a 10s grace period. Which flag combination implements this correctly in podman run?

Accepted Answer

podman run --health-cmd="curl -f http://localhost/ || exit 1" --health-interval=30s --health-timeout=5s --health-retries=3 --health-start-period=10s webapp. The --health-cmd, --health-interval, --health-timeout, --health-retries, and --health-start-period options configure container health checks.

Answer

podman run --healthcheck="curl -f http://localhost/" --interval=30 --timeout=5 --retries=3 webapp

Answer

podman run --health-probe="curl -f http://localhost/" --health-delay=10s webapp

Answer

podman run --check-command="curl -f http://localhost/" --check-period=30s webapp

Question 3

You need to set a persistent environment variable named 'APP_PORT' with the value '8080' inside a container image via the Containerfile. Which instruction should you use?

Accepted Answer

ENV APP_PORT=8080. The ENV instruction sets environment variables that persist when the container runs.

Answer

EXPORT APP_PORT=8080

Answer

VAR APP_PORT=8080

Answer

SET APP_PORT=8080

Question 4

An administrator has created a systemd service file named container-web.service using podman generate systemd. Where should this file be placed for a rootless user to manage it as a user-level service?

Accepted Answer

~/.config/systemd/user/. Rootless systemd service files for user sessions must be placed in the user's systemd user directory.

Answer

~/.local/share/podman/systemd/

Answer

/etc/systemd/system/

Answer

/var/lib/containers/systemd/

Question 5

You need to ensure that a file copied into your image via the COPY instruction is owned by a specific user 'developer' and group 'devgroup'. How can this be achieved efficiently?

Accepted Answer

COPY --chown=developer:devgroup app.py /app/app.py. The COPY instruction supports the --chown flag to set ownership during the copy operation.

Answer

COPY app.py /app/app.py && chown developer:devgroup /app/app.py

Answer

COPY --user=developer:devgroup app.py /app/app.py

Answer

ADD --owner=developer app.py /app/app.py

Question 6

Which THREE directives or practices are associated with implementing secure container builds and adhering to least-privilege principles? (Choose three.)

Accepted Answer

Using minimal, trusted base images to reduce the total software footprint and vulnerability surface.. Secure builds involve using non-root users, secure secret mounting, and trusted base images.

Answer

Hardcoding database passwords directly into ENV instructions so the application can read them easily.

Answer

Running all RUN instructions with '--privileged' inside the Containerfile.

Question 7

A container named db_master was previously paused using podman pause. Which command should the administrator use to resume its execution?

Accepted Answer

podman unpause db_master. podman unpause unfreezes the processes within the paused container.

Answer

podman start db_master

Answer

podman resume db_master

Answer

podman thaw db_master

Question 8

A container named 'worker' was configured with a health check command during build time, but an administrator needs to temporarily override or define a new health check command while running the container. Which flag should be passed to 'podman run' to achieve this?

Accepted Answer

--health-cmd. The '--health-cmd' flag allows defining or overriding the health check command when starting a container.

Answer

--check-command

Answer

--healthcheck-run

Answer

--health-test

Question 9

A developer wants to build a container image using podman build, but the Containerfile is named 'Customfile' and located in a subdirectory named 'dockerfiles'. Which command accomplishes this?

Accepted Answer

podman build -f dockerfiles/Customfile .. The -f flag specifies the path to the Containerfile relative to the build context.

Answer

podman build --file-path dockerfiles/Customfile .

Answer

podman build -p dockerfiles/Customfile .

Answer

podman build --config dockerfiles/Customfile .

Question 10

Which THREE statements accurately describe the differences between shell form and exec form for CMD and ENTRYPOINT instructions? (Choose three.)

Accepted Answer

Exec form ensures that Unix signals (such as SIGTERM) sent by Podman are received directly by the application process as PID 1.. Exec form uses JSON array syntax, avoids running a shell, and correctly passes signals as PID 1.

Answer

Shell form is mandatory when using multi-stage builds.

Answer

Exec form allows shell variable expansion (like $VAR) directly without needing explicit shell invocation.

Question 11

An administrator wants to forcefully kill a running container named runaway_job immediately by sending the SIGKILL signal. Which command should be used?

Accepted Answer

podman kill runaway_job. podman kill sends signals to containers, defaulting to SIGKILL.

Answer

podman terminate runaway_job

Answer

podman halt runaway_job

Answer

podman stop --force runaway_job

Question 12

Which instruction should be used in a Containerfile to copy local files from the host machine into the container filesystem?

Accepted Answer

COPY. The COPY instruction takes files from the local context and adds them to the container's filesystem.

Answer

TRANSFER

Answer

ADD

Answer

MOVE

Question 13

A container named api_gw is configured with a health check. An administrator needs to check the current health status (e.g., healthy, unhealthy, starting) using the command line without reading the full inspect JSON. Which command string achieves this?

Accepted Answer

podman inspect --format='{{json .State.Health.Status}}' api_gw. Using format strings with podman inspect allows extracting specific fields like the health status directly.

Answer

podman health status api_gw

Answer

podman ps --filter health=unhealthy

Answer

podman status api_gw

Question 14

An administrator needs to view the processes running inside a specific container named worker_node, along with custom ps options like -ef to see full command arguments. Which command accomplishes this?

Accepted Answer

podman top worker_node -ef. podman top displays the running processes of a container and accepts ps-compatible argument flags.

Answer

podman ps --processes worker_node

Answer

podman exec worker_node ps -ef

Answer

podman inspect --processes worker_node

Question 15

A security engineer is troubleshooting why signature verification fails when pulling an image from a trusted registry. The policy file (/etc/containers/policy.json) specifies 'signedBy' using a GPG key, but the transport uses 'dir://'. Where must the public GPG key be imported for Podman to successfully verify the signature?

Accepted Answer

Into the local GnuPG keyring using 'gpg --import'. Public keys used for verification must be imported into the local GPG keyring managed by GnuPG.

Answer

Into ~/.config/containers/policy.d/keys/

Answer

Into /etc/containers/certs.d/keys/

Answer

Into /var/lib/containers/sigstore/

Question 16

An administrator needs to inspect low-level configuration, network settings, and state details of a running container named redis_cache in JSON format. Which command provides this?

Accepted Answer

podman inspect redis_cache. podman inspect provides detailed configuration and state information about containers, images, and other objects in JSON.

Answer

podman show redis_cache

Answer

podman details redis_cache

Answer

podman query --json redis_cache

Question 17

An administrator is troubleshooting container exit codes. A container exited with code 137. What does this specific exit code typically signify in container engines?

Accepted Answer

The container was terminated forcefully by SIGKILL (often due to Out-Of-Memory).. Exit code 137 indicates that the container process was terminated forcibly by the OOM killer or SIGKILL (128 + 9).

Answer

The container executed an invalid system call blocked by seccomp.

Answer

The container encountered an application-level syntax error.

Answer

The container startup script had a permission denied error.

Question 18

An administrator wants to view the last 50 lines of logs for a running container named log_test and keep the log stream open for new entries. Which command should be used?

Accepted Answer

podman logs --tail 50 --follow log_test. The --tail and --follow (or -f) flags in podman logs control line limits and streaming.

Answer

podman tail 50 log_test

Answer

podman log-stream --lines=50 log_test

Answer

podman inspect --tail=50 log_test

Question 19

An administrator needs to inspect running containers and their resource consumption. Which TWO commands provide information about running container state or resource usage? (Choose TWO)

Accepted Answer

podman stats. podman ps lists containers, and podman stats displays live resource usage statistics.

Answer

podman storage

Answer

podman images

Answer

podman network ls

Question 20

A container named 'app_prod' is currently running, and an operator needs to troubleshoot its current configuration, network settings, and mounted volumes in detail. Which THREE commands or approaches can retrieve this information? (Choose THREE)

Accepted Answer

Run 'podman inspect app_prod' to output comprehensive JSON-formatted metadata regarding configuration, mounts, and network settings.. Podman provides several ways to inspect running containers, including 'podman inspect', 'podman port', and 'podman exec' / 'podman top'.

Answer

Run 'podman config app_prod' to print a summary of environment variables and limits.

Answer

Run 'podman diff app_prod' to view changes to the container's file system, which is primarily used for tracking modifications rather than initial configuration.